Microchip Technology dsPICDEM MC1H User manual

2003 Microchip Technology Inc. DS70096A
dsPICDEM™
MC1H 3-Phase
High Voltage Power Module
User’s Guide

DS70096A-page ii 2003 Microchip Technology Inc.
Information contained in this publication regarding device
applications and the like is intended through suggestion only
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
No representation or warranty is given and no liability is
assumed by Microchip Technology Incorporated with respect
to the accuracy or use of such information, or infringement of
patents or other intellectual property rights arising from such
use or otherwise. Use of Microchip’s products as critical
components in life support systems is not authorized except
with express written approval by Microchip. No licenses are
conveyed, implicitly or otherwise, under any intellectual
property rights.
Trademarks
The Microchip name and logo, the Microchip logo, dsPIC,
KEELOQ, MPLAB, PIC, PICmicro, PICSTART, PRO MATE and
PowerSmart are registered trademarks of Microchip
Technology Incorporated in the U.S.A. and other countries.
FilterLab, microID, MXDEV, MXLAB, PICMASTER, SEEVAL
and The Embedded Control Solutions Company are
registered trademarks of Microchip Technology Incorporated
in the U.S.A.
Accuron, Application Maestro, dsPICDEM, dsPICDEM.net,
ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-
Circuit Serial Programming, ICSP, ICEPIC, microPort,
Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM,
PICC, PICkit, PICDEM, PICDEM.net, PowerCal, PowerInfo,
PowerMate, PowerTool, rfLAB, rfPIC, Select Mode,
SmartSensor, SmartShunt, SmartTel and Total Endurance are
trademarks of Microchip Technology Incorporated in the
U.S.A. and other countries.
Serialized Quick Turn Programming (SQTP) is a service mark
of Microchip Technology Incorporated in the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
© 2003, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
Note the following details of the code protection feature on Microchip devices:
• Microchip products meet the specification contained in their particular Microchip Data Sheet.
• Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip's Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
• Microchip is willing to work with the customer who is concerned about the integrity of their code.
• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Microchip received QS-9000 quality system
certification for its worldwide headquarters,
design and wafer fabrication facilities in
Chandler and Tempe, Arizona in July 1999
and Mountain View, California in March 2002.
The Company’s quality system processes and
procedures are QS-9000 compliant for its
PICmicro®8-bit MCUs, KEELOQ®code hopping
devices, Serial EEPROMs, microperipherals,
non-volatile memory and analog products. In
addition, Microchip’s quality system for the
design and manufacture of development
systems is ISO 9001 certified.

© 2003 Microchip Technology Inc. DS70096A-page iii
dsPICDEM™ MC1H 3-PHASE
HIGH VOLTAGE POWER MODULE
Safety Notice
The safety notices and operating instructions provided should be adhered to, to
avoid a safety hazard. If in any doubt, consult your supplier.
WARNING – This system must be earthed (grounded) at all times.
CAUTION – The system should not be installed, operated, serviced or modified
except by qualified personnel who understand the danger of electric shock
hazards and have read and understood the user instructions. Any service or
modification performed by the user is done at the user’s own risk and voids all
warranties.
WARNING – The output terminals are NOT isolated from the incoming AC mains
supply and may be at up to 410V with respect to ground, regardless of the input
mains supply voltage applied. These terminals are live during operation AND for
3 minutes after disconnection from the supply. Do not attempt to access the
terminals or remove the cover during this time. Note that this same shock hazard
applies to any external brake resistor connected, which will also be live, and
therefore protection equivalent to double insulation should be provided.
WARNING – The unit may obtain power through the output terminals if these are
connected to a rotating motor acting as a generator. If this is the case, then the
previous warning also applies (i.e., the output terminals are live when connected
to the generator and for 3 minutes after the generator has been stopped). Note
that this case can arise even when the unit has been disconnected from the
incoming AC mains supply.
CAUTION – If a motor is connected to the output of this unit, the frame should be
connected to the output protective ground terminal provided. Particular care
should be taken to mechanically guard such a motor, bearing in mind that
unexpected behavior is likely to result from the process of code development.
CAUTION – For continued protection against the risk of fire, replace the fuse with
one of the same type only (i.e., T5A H 250V, Time Lag 5A High Breaking Capacity
250V minimum).

dsPICDEM™ MC1H 3-Phase High Voltage Power Module
DS70096A-page iv © 2003 Microchip Technology Inc.
• The system is intended for evaluation and development purposes and
should only be operated in a normal laboratory environment as defined by
IEC 61010-1:2001.
• Clean with a dry cloth only.
• Operate flat on a bench, do not move during operation and do not block the
ventilation holes.
• The system should not be operated without all the supplied covers fully
secured in place.
• Screws should not protrude into the unit by more than 5 mm (0.2″), type M3
ISO metric.
• The system should not be connected or operated if there is any apparent
damage to the unit.
• The unit is designed for installation category II and to be connected to the
AC mains supply via a standard non-locking plug. As the unit has no mains
switch, this plug constitutes the means of disconnection from the supply
and thus the user must have unobstructed access to this plug during
operation.

2003 Microchip Technology Inc. DS70096A-page v
dsPICDEM™ MC1H 3-PHASE
HIGH VOLTAGE POWER MODULE
Table of Contents
Safety Notice ............................................................................................................................ iii
Preface........................................................................................................................................ 1
Chapter 1. Set Up and Operation
1.1 Introduction ................................................................................................................... 5
1.2 Using The Motor Control 3-Phase High Power Module ................................................ 7
1.3 Current and Power Limitations.................................................................................... 14
1.4 Detailed Description of Operation ............................................................................... 17
1.5 Modifying The Board ................................................................................................... 30
1.6 Test Points .................................................................................................................. 36
1.7 User Signal Connector Pinout (37-Pin, D-Type) ......................................................... 37
Appendix A: Circuit Diagrams ........................................................................................... 39
Appendix B: Source Code................................................................................................... 47
Worldwide Sales and Service.............................................................................................. 54

dsPICDEM™ MC1H 3-Phase High Voltage Power Module
DS70096A-page vi © 2003 Microchip Technology Inc.
NOTES:

© 2003 Microchip Technology Inc. DS70096A-page 1
dsPICDEM™ MC1H 3-PHASE
HIGH VOLTAGE POWER MODULE
Preface
This chapter contains general information about this manual and contacting customer
support.
HIGHLIGHTS
Topics covered in this chapter:
• About this Guide
• Warranty Registration
• Recommended Reading
• The Microchip Web Site
• Development Systems Customer Notification Service
• Customer Support
ABOUT THIS GUIDE
Document Layout
This document describes how to use the Microchip dsPICDEM™MC1H High Voltage
3-Phase Power Module. The manual layout is as follows:
•Chapter 1: Set Up and Operation – Describes what the product is, what makes it
a desirable development tool, how to install it and the basic features of the
interface.
•Worldwide Sales and Service – Lists Microchip sales and service locations and
telephone numbers worldwide.
Documentation Updates
All documentation becomes dated and this user’s guide is no exception. Since
MPLAB®IDE, MPLAB C1X and other Microchip tools are constantly evolving to meet
customer needs, some actual dialogs and/or tool descriptions may differ from those in
this document. Please refer to our web site to obtain the latest documentation available.
Documentation Numbering Conventions
Documents are numbered with a “DS” number. The number is located on the bottom of
each page, in front of the page number. The numbering convention for the DS Number
is: DSXXXXXA,
where:
XXXXX = The document number.
A = The revision level of the document.

dsPICDEM™ MC1H 3-Phase High Voltage Power Module
DS70096A-page 2 © 2003 Microchip Technology Inc.
WARRANTY REGISTRATION
Please complete the enclosed Warranty Registration Card and mail it promptly.
Sending in your Warranty Registration Card entitles you to receive new product
updates. Interim software releases are available at the Microchip web site.
RECOMMENDED READING
This user’s guide describes how to use the dsPICDEM MC1H 3-Phase High Voltage
Power Module. The data sheets contain current information on programming the
specific microcontroller devices.
THE MICROCHIP WEB SITE
Microchip provides online support on the Microchip World Wide Web (WWW) site. The
web site is used by Microchip as a means to make files and information easily available
to customers. To view the site, you must have access to the Internet and a web browser
such as Netscape Navigator®or Microsoft®Internet Explorer.
The Microchip web site is available by using your favorite Internet browser to attach to:
http://www.microchip.com
The web site provides a variety of services. Users may download files for the latest
development tools, data sheets, application notes, user's guides, articles and sample
programs. A variety of information specific to the business of Microchip is also
available, including listings of Microchip sales offices, distributors and factory
representatives.
Technical Support
• Frequently Asked Questions (FAQ)
• Online Discussion Groups - Conferences for products, Development Systems,
technical information and more
• Microchip Consultant Program Member Listing
• Links to other useful web sites related to Microchip products
Engineer's Toolbox
•DesignTips
• Device Errata
Other available information
• Latest Microchip Press Releases
• Listing of seminars and events
• Job Postings

© 2003 Microchip Technology Inc. DS70096A-page 3
Preface
DEVELOPMENT SYSTEMS CUSTOMER NOTIFICATION SERVICE
Microchip started the customer notification service to help our customers keep current
on Microchip products with the least amount of effort. Once you subscribe, you will
receive e-mail notification whenever we change, update, revise or have errata related
to your specified product family or development tool.
Go to the Microchip web site at (http://www.microchip.com) and click on Customer
Change Notification. Follow the instructions to register.
The Development Systems product group categories are:
• Compilers
•Emulators
• In-Circuit Debuggers
•MPLAB
® Development Systems
• Programmers
Here is a description of these categories:
Compilers – The latest information on Microchip C compilers and other language
tools. These include the MPLAB C17, MPLAB C18 and MPLAB C30 C compilers;
MPASM™ and MPLAB ASM30 assemblers; MPLINK™ and MPLAB LINK30 object
linkers; MPLIB™ and MPLAB LIB30 object librarians.
Emulators – The latest information on Microchip in-circuit emulators. This includes the
MPLAB®ICE 2000 and MPLAB®ICE 4000.
In-Circuit Debuggers – The latest information on Microchip in-circuit debuggers.
These include the MPLAB®ICD and MPLAB ICD 2.
MPLAB Development Systems – The latest information on Microchip MPLAB®IDE,
the Windows®Integrated Development Environment for development systems tools.
This list is focused on the MPLAB®IDE, MPLAB SIM and MPLAB SIM30 simulators,
MPLAB IDE Project
Manager and general editing and debugging features.
Programmers – The latest information on Microchip device programmers. These
include the PRO MATE®II device programmer and PICSTART®Plus development
programmer.

dsPICDEM™ MC1H 3-Phase High Voltage Power Module
DS70096A-page 4 © 2003 Microchip Technology Inc.
CUSTOMER SUPPORT
Users of Microchip products can receive assistance through several channels:
• Distributor or Representative
• Local Sales Office
• Field Application Engineer (FAE)
• Corporate Applications Engineer (CAE)
• Hotline
Customers should call their distributor, representative or field application engineer
(FAE) for support. Local sales offices are also available to help customers. See the
back cover for a list of sales offices and locations.
Corporate Applications Engineers (CAEs) may be contacted at [phone].
In addition, there is a Systems Information and Upgrade Line. This line provides system
users a list of the latest versions of all of Microchip's development systems software
products. Plus, this line provides information on how customers can receive any
currently available upgrade kits.
The Hotline Numbers are:
1-800-755-2345 for U.S. and most of Canada.
1-480-792-7302 for the rest of the world.

© 2003 Microchip Technology Inc. DS70096A-page 5
dsPICDEM™ MC1H 3-PHASE
HIGH VOLTAGE POWER MODULE
Chapter 1. Set Up and Operation
1.1 INTRODUCTION
The Microchip dsPICDEM MC1H 3-Phase High Voltage Power Module is intended to
aid the user in the rapid evaluation and development of a wide variety of motor control
applications using the dsPIC®microcontroller. The design of the system includes
Microchip analog components, as well as a PIC®microcontroller used to provide
isolated voltage feedback. The main components of the system are shown in
Figure 1-2.
The rated continuous output current from the inverter is 2.5A (RMS). This allows up to
approximately 0.8 kVA output when running from a 208V to 230V single-phase input
voltage in a maximum 30°C (85F) ambient temperature environment. Thus, the system
is ideally suited to running a standard 3-Phase Induction Motor of up to 0.55 kW
(0.75 HP) rating or an industrial servomotor of slightly higher rating. The power module
is capable of driving other types of motors and electrical loads that do not exceed the
maximum power limit and are predominantly inductive. Furthermore, single-phase
loads can be driven using 1 or 2 of the inverter outputs.
The unit is capable of operating from any AC voltage up to a maximum of 265V.
Operation at voltages beneath 208V requires that the output power is reduced owing
to inverter output and AC input stage current limits. A more detailed explanation of
power limitations is given in Section 1.4 “Detailed Description of Operation”.
The user should read Section 1.3 “Current and Power Limitations” and Section
1.4 “Detailed Description of Operation” carefully before using the system.
FIGURE 1-1: POWER MODULE WITH ATTACHED DEVELOPMENT BOARD
(SOLD SEPARATELY)

dsPICDEM™ MC1H 3-Phase High Voltage Power Module
DS70096A-page 6 © 2003 Microchip Technology Inc.
FIGURE 1-2: MC1H 3-PHASE HIGH VOLTAGE POWER MODULE BLOCK DIAGRAM
PICmicro®
MCU
DC Bus Voltage DC Bus Current
Brake Chopper
R
R, Y, B Switch Current
Live
Neutral
0 - 265V AC
Power Factor
Corrector
Isolated DC Input
Current Feedback
YB
R & Y Isolated Phase Current Feedback
3 4
5 6
7 8
12
Vac
Feedback Optoisolation
Fault
Detection
Vac
DC BUS Voltage
Gate Drive Optoisolation
Live Side
Isolated Side
Brake Switch
Current
To
Control
Board
From
Control
Board
To Gate
Drive 1-8

© 2003 Microchip Technology Inc. DS70096A-page 7
Set Up and Operation
1.2 USING THE MOTOR CONTROL 3-PHASE HIGH POWER MODULE
1.2.1 Introduction
The user should be aware of the operating procedures outlined below and ensure that
they are followed. Failure to do so may result in damage to the system.
1.2.2 Making Power Connections
It is recommended that cables be terminated with blue or red insulated crimp
terminals. If crimp terminals are not used, care should be taken to ensure that stray
strands of wire do not short to adjacent terminals or the enclosure. If possible, all
wires should be stripped and tinned with solder before connecting to the power
module terminals.
For the AC mains supply input, standard double-insulated, 3-core flex cable should be
used with a minimum current rating of 10A (1 mm218 AWG). A computer power cable
can be used when the IEC connector is removed.
The recommended output cable size is 1.0 to 1.5 mm2(18-16 AWG) and it should
have a 600V rating. This cable should also be double insulated or have a protective
ground screen.
Access to the terminal screws is provided via holes in the lid of the enclosure. A flat
blade screwdriver should be used.
The power connections are shown in Table 1-1 and Figure 1-3:
TABLE 1-1: POWER CONNECTIONS
Note: The system is designed for installation category II. Therefore, the incoming
mains cable should be wired into a standard non-locking 2-pin + ground
type plug.
Note: The user should only access the power terminals when the system is fully
discharged (see Safety Notice).
Connection Number Input Output
1 Ground Ground
2 Neutral Red Phase
3 Live (Fused) Yellow Phase
4 — Blue Phase
5 — -DC Bus
6 — External Brake Resistor
7—+DCBus

dsPICDEM™ MC1H 3-Phase High Voltage Power Module
DS70096A-page 8 © 2003 Microchip Technology Inc.
FIGURE 1-3: POWER CONNECTIONS
Using output connections 6 and 7, the user may connect an external braking resistor.
The user should consider the maximum and average power to be dissipated at the
required DC bus voltage when considering the resistor value. They should also
consider the peak allowable resistor current of 4A. For example, if regulating at 400V
then a 100Ωminimum value should be used which would allow 1.6 kW (at most) to be
dissipated.
The user may feed in an external DC supply using output connections 5 and 7. This
offers the simplest way for a user to bypass the PFC section of the unit. In the simplest
case all the user needs to do is use an external rectifier and fuse. The input current
rating when using the auxiliary DC input is 15A (RMS). The inverter output rating is
unchanged. Note that if using the auxiliary DC input, the internal fuse, soft-start, PFC
and ground FAULT protection is bypassed. It is up to the user to ensure adequate
external protection circuitry is used and incoming DC voltage is correctly regulated.
1.2.3 Connecting To The Control Board
The system has been designed so that the Microchip dsPICDEM MC1 Motor Control
Development Board (02-01648) plugs directly into the 37-pin, D-Type connector.
Section 1.7 “User Signal Connector Pinout (37-Pin, D-Type)” contains details of
the pin allocation.
Correct operation with the use of an extension cable can not be guaranteed as it may
introduce additional noise. If an extension is used, it should be as short as possible
and use screened cable.
The power module derives its low voltage power supplies from the control PCB. The
supplies on the isolated supply are taken directly from the control PCB via the 37-pin
connector. The supplies on the live side of the isolation barrier are derived using an
isolating DC-DC converter that is connected to the digital +5V supply input on the
37-pin connector. In this way, the power module may be used at any input voltage up
to the maximum. This arrangement is shown in Figure 1-4.
7
6
5
4
3
2
1
3
2
1
Input
Output

© 2003 Microchip Technology Inc. DS70096A-page 9
Set Up and Operation
FIGURE 1-4: POWER ELECTRONICS GATE DRIVE STAGES
Note that the incoming digital 0V from the development board is grounded within the
power module (as shown in Figure 1-4) to ensure user safety. When a PC or any other
device is connected to the control board there is therefore the possibility of a “ground
loop” occurring. If this is suspected, the user should first try to eliminate the stray
magnetic field causing the problem by relocating the offending transformer or by using
shielding. If this is not possible, then the equipment connected to the development
board should be isolated from the digital 0V.
Position and speed feedback transducers are connected to the control board directly
and not via the power module. No electrical isolation is provided on the control board
for these signals and so the transducers must be isolated.
Consult the development board documentation for details of signal interfacing and
how to connect in-circuit emulators and debugging equipment.
POWER ELECTRONICS GATE DRIVE
STAGES
ISOLATED
HALL-EFFECT
CURRENT
TRANSDUCERS
CONDITIONING
OF LIVE
FEEDBACK
SIGNALS
FAULT
DETECTION
AND LATCHING
CIRCUITRY
OPTOCOUPLERS
5V LINEAR
REGULATOR
INCOMING GROUND
CONNECTED TO
CHASSIS
+15V OUT
LIVE
ISOLATED
ISOLATING
DC : DC
CONVERTER
Pin 27
Pin 9
Pin 18&36 Pin 19&37
9V Power
Supply Input
(Floating)
Rectify
Smooth and
Regulate
Digital +5V
Digital 0V
To Digital
Circuits
To Analog
Circuits
Analog +5V
Analog 0V
Control PCB 02-01648
Power PCB 02-01647

dsPICDEM™ MC1H 3-Phase High Voltage Power Module
DS70096A-page 10 © 2003 Microchip Technology Inc.
1.2.4 Power-Up/Power-Down Sequence
The user should ensure that the following sequence are followed.
1.2.4.1 POWER-UP SEQUENCE
• With the development board plugged in, turn on the power supply feeding the
control PCB (if not already on).
• One or more of the fault lights may illuminate. This is normal.
• Turn on the AC supply to the power module.
• Reset the system by activating the active high ISO_RESET line. The ISO_RESET
line is on pin 33 of the 37-pin, D-type (see Section 1.7 “User Signal Connector
Pinout (37-Pin, D-Type)”). If using the dsPICDEM MC1 Motor Control
Development Board, this signal is routed to pin 14 of the 30F6010 dsPIC device,
which is on Port RE9. The minimum pulse width for the RESET is 2 µs. The
RESET should be done in coordination with the SPI™ handling routine of the
dsPIC device to ensure correct synchronization of the serial interface providing
the isolated voltage feedback (see Section 1.2.6.2 “Isolated Feedback” and
Section 1.4.7.2 “Isolated Voltage Feedback”). The system is now ready to use.
1.2.4.2 POWER-DOWN SEQUENCE
• Stop firing all power devices.
• Turn off the incoming AC supply.
• Wait until the red DC bus LED indicator visible through the ventilation holes in the
top of the unit has gone out (this will take 3 minutes or less).
• Turn off the power supply feeding the control card (if required).
1.2.5 Power Device Switching Frequencies
The PFC stage has been designed for a switching frequency of 50 kHz (±5%).
This offers a good system compromise between cost, size and efficiency. The
modulation frequency affects not only the losses in the power switches and diode but
also that in the PFC inductor and snubbing components. The user should not deviate
from the stated carrier frequency. The user should note that a typical regulation level
for the DC bus is between 350-400V.
If the user does not wish to use the PFC stage the PFC switches can simply be
left off. However, the PFC inductor and diode will be left in circuit and the input
current will remain limited to 5A (RMS) and 8.9A Peak. The user should read Section
1.5.3.3 “Bypassing The PFC” if this is unacceptable.
The Brake chopper switch has been designed so that it may be switched up to a
maximum frequency of 16 kHz. This frequency limit is chosen for power dissipation
and low voltage power supply consumption reasons. In most braking applications a
lower modulation frequency will be used, as there is little benefit (apart from acoustic
noise) from modulating at such a high frequency.
The six inverter switches have been designed so that they may be switched up
to a maximum frequency of 20 kHz. This frequency limit is chosen for power
dissipation and low voltage power supply consumption reasons. Unless extremely low
output current harmonics or very high bandwidth control is required, it is suggested
that a 16 kHz carrier frequency be used. This offers lower loss while still being
inaudible. It also has the advantage that the dead time insertion will cause less
distortion of the output voltage.

© 2003 Microchip Technology Inc. DS70096A-page 11
Set Up and Operation
Given the high side and low side switches of the inverter are connected in series
across the DC bus (see Figure 2.1), both switches should never be turned on at the
same time. Turning both switches on effectively places a short circuit across the DC
bus and is called “Shoot Through”. Shoot Through should be avoided at all costs. In
order to avoid Shoot Through, an appropriate time delay must be inserted between
the turn off command to one device and the turn on command to the other device of
the same inverter leg. This time is called the “Dead Time”. The required Dead Time
depends on the switching speeds of the power devices and the timing delays due to
the optocouplers and the gate drive circuits.
Writing to the appropriate registers in the dsPIC device (DTCON1 and DTCON2) sets
the dead time. Refer to the dsPIC30F Family Reference Manual (DS70046) for details.
Although not necessary for correct operation of the system, it is common practice to
eliminate very narrow firing commands. This is because they will have negligible effect
on the output waveform but incur additional switching loss. It is suggested that a duty
cycle that gives transistor on or off times of less than 100 ns be eliminated by rounding
the duty cycle up or down as appropriate. Note that pulses, which are narrower than
the dead time set in the Motor Control PWM Module, are automatically eliminated.
In order to provide an economic design, so-called bootstrap power supplies are used
for the high side inverter switches (see Section 1.4.3.3 “Gate Drive” for details). As
the charging path for these is only made when the corresponding low side switch or
diode conducts, this places some minor restrictions on modulation. These are as
follows:
1. When the power module is first energized after a period of time where no
modulation has taken place, all low side switches should be turned on for 2-3 µs.
This ensures the bootstrap supplies are “primed”. This can be simply done by
using the output override facility in the dsPIC Motor Control PWM module by
setting the correct bits in the OVDCON register. Care should be taken to ensure
a shoot through does not accidentally occur. The possibility of a shoot through
fault will be minimized if the dsPIC PWM module is operated in the
complementary Output mode (module default).
2. If the user is continuously modulating all the low side switches as part of their
PWM strategy, the “priming” step is not strictly necessary, as it will happen
automatically. There will however be a delay of variable duration before the high
side switches actually fire. The delay will depend on the particular operating
circumstances and whether it is acceptable or not will depend on the particular
application.
3. In extreme circumstances, it is possible that the high side bootstrap supply will
discharge while the system is running. This will not happen for typical sinusoidal
modulation schemes provided an inductive load (e.g., a motor) is connected. If a
bootstrap supply collapses, an under-voltage lockout will automatically occur to
protect the high side switch entering the linear region of operation. The high side
switch is turned off whatever the command. The lockout is automatically cleared
when the bootstrap supply is restored and the next turn-on edge occurs. If
necessary, the user should periodically apply a refresh pulse to the low side
switch in a similar manner to that described for priming above.
Note: No hardware Dead Time is included in the design as it is included as a
feature of the Motor Control PWM Module of the dsPIC device. A minimum
Dead Time of 2 µs should be used. This applies to both turn on and turn off
of both devices.
Note: The user should verify that all PWM frequencies and dead time settings are
correct using an oscilloscope before connecting the control signals to the
power module.

dsPICDEM™ MC1H 3-Phase High Voltage Power Module
DS70096A-page 12 © 2003 Microchip Technology Inc.
1.2.6 Power Module Feedback Signals
1.2.6.1 INTRODUCTION
The power module may be operated in two distinct ways with respect to signal
isolation. This effects which of the feedback signals are available. All feedback signals
are preconditioned and scaled within the power module. Which particular set of
feedback signals the user requires will change depending on the application. Typically
industrial applications tend to use isolated signals for both safety, noise and
performance reasons. More cost-sensitive applications, and especially those that
have little or no user input, tend to run the control electronics live and use non-isolated
feedback signals.
1.2.6.2 ISOLATED FEEDBACK
Table 1-2 gives the scaling of the isolated feedback signals as the system is delivered.
TABLE 1-2: ISOLATED SCALING
1.2.6.3 NON-ISOLATED FEEDBACK
As the system is delivered, access is not given to the non-isolated feedback signals to
ensure user safety. If an experienced user wishes to access these signals they should
read Section 1.4 “Detailed Description of Operation” along with Section
1.5.3.4 “Accessing the Additional (non-isolated) Feedback Signals”. Note that
once the isolation barrier is bridged, all signals can no longer be considered to be
isolated from the power circuit. When operating in the non-isolated configuration, the
Hall current sensors and SPI voltage feedback signals are also available.
The scaling for the signals as the system is delivered is given below. For details of
changing the scaling, see Section 1.5.3 “Changing Current Feedback and Trip
Scaling”.
TABLE 1-3: NON-ISOLATED SCALING
Feedback Signal Scaling
Inverter Output (R and Y) Hall Current Sensor 2.4 A/V with 2.5V = 0A
DC Input Hall Current Sensor 4.8 A/V with 2.5V = 0A
DC Bus Voltage via SPI™ Channel 230 = 410V (1LSB = 1.78V)
Rectified AC Voltage (|VAC|) via SPI Channel 230 = 369V (1LSB = 1.60V)
Feedback Signal Scaling
R, Y, B Inverter Leg Shunts 2.4 A/V with 2.5V = 0A*
DC Bus Shunt 2.38 A/V with 2.5V = 0A*
Brake Chopper Shunt 1.09 A/V
DC Bus Voltage 91.0 V/V
|VAC| Voltage 81.9 V/V
R. Y, B Inverter Output Voltages 92.0 V/V
* If a large rate of change of current occurs due to the use of a load with low inductance, the
voltage across the self-inductance of the shunts will cause an additional shunt voltage
that will add to the shunt feedback signals.

© 2003 Microchip Technology Inc. DS70096A-page 13
Set Up and Operation
1.2.7 FAULT Protection
The following FAULT protection is provided which automatically disables all firing
independent of the inputs on the 37-pin connector.
TABLE 1-4: FAULT PROTECTION
To reset a FAULT, assert the ISO_RESET line of the 37-pin connector. This should be
done for a minimum time of 2 µs. The RESET must be carried out in coordination with
the SPI handling routine of the dsPIC device to ensure correct synchronization of the
serial interface providing the isolated voltage feedback (see Section 1.4.7.2 “Isolated
Voltage Feedback”).
1.2.8 Operation at Low Output Frequencies and Stall
As far as the inverter power devices are concerned, it is the instantaneous
temperatures of their junctions that matter for correct operation and reliability. As the
current that flows through a particular power device changes through an electrical
cycle so does the loss. At high fundamental output frequencies (e.g., 60 Hz), the
devices have sufficient thermal “mass” to smooth out much of the effect of the
variation in loss, so that the peak device junction is due to the (much lower) average
dissipation. As the output frequency reduces, the peak device junction temperature
reaches the worst case loss.
It is common practice to include a stall detection algorithm in software. This is
designed to not only protect the power components, but also the motor from thermal
overload. As it is impractical to include stall detection in hardware that maintains
flexibility for development but still provides 100% protection, it is assumed that the
software in the dsPIC device provides this feature. The algorithm should monitor rotor
speed and cause a system trip if the rotor speed is at or near zero for greater than an
appropriate length of time while the inverter is energized. A stall trip time of 2 seconds
is suggested.
Fault Source Nominal Trip
Level LED Indicator
R, Y, B Bottom Switch Current ±4.8A* Shunt Overcurrent
DC Bus Current ±4.8A*
DC Bus Voltage 410V Over Voltage
Brake Switch Current +4.9A Brake Overcurrent
Heat sink Over Temperature 65°C (150F) Over Temperature
Isolated DC Input Current Feedback +8.9A Hall Overcurrent
R, Y Isolated Phase Current Feedback ±4.4A
* If a large rate of change of current occurs due to the use of a load with low inductance, the
voltage across the self-inductance of the shunts will cause trips to occur at a lower level
than that stated.
Note: If SHUNT OVERCURRENT trips are occurring, but not HALL
OVERCURRENT trips, this may indicate that an inverter Shoot Through is
occurring. The user should immediately remove AC power from the system
and check that the correct 2 µs dead time exists on the inverter firing signals
using an oscilloscope.

dsPICDEM™ MC1H 3-Phase High Voltage Power Module
DS70096A-page 14 © 2003 Microchip Technology Inc.
1.2.9 Field Weakening
If the user is operating a brushless permanent magnet motor using field weakening by
employing phase advance, great care should be taken. If a FAULT trip occurs, firing
will stop, and the full back EMF magnitude, due to the motor's speed, will be present
on the output terminals. Should the peak of the back EMF be above the DC bus,
sudden uncontrolled motor braking will occur. The DC bus will rise in an uncontrolled
manner possibly causing damage to both power devices and the DC bus capacitors. A
speed greater than that which would produce a peak back EMF of greater than 450V,
with no field weakening, should not be used. This should adequately protect the unit. If
using the auxiliary DC input, the user should check the rating of the power supply and
adjust this speed accordingly or use a series blocking diode of suitable rating.
The same care should be taken with separately excited brushed DC motors if
employing field weakening at high speed. If the field current were to be increased in
error, a similar braking phenomenon may occur if the back EMF rises above the DC
bus. The effect is likely to be less severe as a DC over-voltage will occur tripping out
both the armature and field supply (assuming the field is not supplied separately). For
this reason, if using a separately excited DC motor it is recommended that both the
field and the armature are supplied from the unit.
1.3 CURRENT AND POWER LIMITATIONS
The maximum power and current capability of the system is dictated by the allowable
temperature rise of the different components. Establishing maximum limits is not
simple given the host of different ways the user may use the system. The voltage and
the nature of the electrical load used both affects the dissipation that occurs. In
determining the allowable limits for the power semiconductors, the following
assumptions have been made:
• Heat sink is at 70°C (worst case over temperature trip point)
• Thermal resistance of the insulating thermal pad is 4°C/W
Note that the maximum power of the system will always be the lower value due to the
AC input stage or the inverter output stage.
1.3.1 Inverter Output Current Limits
The inverter is capable of providing the full rated output of 2.5 A (RMS) within the
entire operating range (voltage, temperature and at up to 20 kHz PWM carrier
frequency) of the system. This includes being continuously stalled at such an
electrical angle that one of the motor phases is at the peak of the rated output (3.5A)
at just less than 100% duty cycle. This is a condition that causes high thermal loading
because one of the inverter switches has the peak worst case conduction and
switching loss continuously. Note that as far as the power devices are concerned,
operation at output frequencies of less than approximately 10 Hz are equivalent to
stall as far as peak device temperature is concerned because of low thermal
capacitance.
In a practical application, this condition of low output frequency/stall and high duty
cycle is unlikely to happen. With a motor correctly matched to the DC bus voltage, the
switch duty cycle at stall will be approximately 50% thus significantly reducing the
conduction loss in a particular switch. The complementary diode of the inverter phase
will also conduct for approximately 50% thus spreading the conduction loss between
two different power device packages. This in turn leads to a substantial reduction in
device temperature.