Rockwell Automation PowerFlex 7000 Instruction manual

PowerFlex® 7000
Medium Voltage AC Drive
TECHNICAL DATA
Firmware Version 7.xxx

Table of Contents
7000-TD002A-EN-P – September 2007
Chapter 1 Introduction ..............................................................................1-1
Description of Operation .........................................................1-2
Speed Command ......................................................................1-3
Speed Reference ......................................................................1-4
Speed Control ..........................................................................1-6
Flux Control .............................................................................1-8
Flux Control for Synchronous Motor ....................................1-10
Current Control ......................................................................1-12
Line Converter Feedback .......................................................1-14
Machine Converter Feedback ................................................1-15
Motor Model ..........................................................................1-16
Drive/Motor Protection ..........................................................1-17
Power Semiconductor Diagnostics ........................................1-19
Off-line Detection of Failed SCRs/SGCTs .....................1-20
Line Converter ..........................................................1-20
Machine Converter ...................................................1-22
On-line Detection of Failed SCRs/SGCTs ......................1-23
Test Modes .............................................................................1-24
Flying Start (Induction Motor) .............................................1-26
Flying Start (Synch Motor) ....................................................1-27
Tachometer/Encoder Option ..................................................1-28
Synchronous Transfer ............................................................1-29
Transfer to Bypass ...........................................................1-31
Transfer to Drive .............................................................1-34
PID Process Control ..............................................................1-35
Power Factor Compensation ..................................................1-38
Analog Outputs ......................................................................1-38
Analog Inputs .........................................................................1-39
Chapter 2 Parameters Parameter Descriptions ............................................................2-1
Parameters Listed by Group ................................................2-199
Parameters Listed by Linear Number ..................................2-217
Alphabetical Index ...............................................................2-229
Linear Number Index ...........................................................2-237
Chapter 3 Troubleshooting Documenting Shutdowns .........................................................3-1
Acronyms and Abbreviations Used in this Manual .................3-2
Drive Fault Messages ..............................................................3-3
Drive Warning Messages .......................................................3-32
Appendix A Logic Command Word – Database 7.xxx................................A-1
Product Specific Logic Command – Firmware 7.xxx ............A-2
Functional
Description
Drive Lo
g
ic Command
and Status

ii Table of Contents
7000-TD002A-EN-P – September 2007

Chapter 1
7000-TD002A-EN-P – September 2007
PowerFlex 7000 Functional Description
Introduction The PowerFlex 7000 is an adjustable speed ac drive in which motor
speed control is achieved through control of the motor torque. The
motor speed is estimated or measured and the torque is adjusted as
required to make the speed equal to the speed command. The motor
and load determine the stator frequency and the drive synchronizes
itself to the motor. This is in contrast to the volts/hertz ac drive in
which the drive determines the stator frequency and does not attempt
to synchronize its output to the motor.
The method of control used in PF7000 is known as direct rotor flux
oriented vector control. The term rotor flux vector control indicates
that the position of the stator current vector is controlled relative to
the motor flux vector. Direct vector control means that the motor
flux is measured, in contrast to the indirect vector control in which
the motor flux is predicted. In both control methods, the stator
current (Is) is split into flux producing component (Isd) and an
orthogonal torque producing component (Isq) which are controlled
independently. The aim of vector control is to allow a complex ac
motor to be controlled as if it were a simple dc motor with
independent, decoupled field and armature currents. This allows the
motor torque to be changed quickly without affecting the flux. For
typical Medium Voltage motors the rotor time constant is in the
range of seconds and therefore the flux cannot be changed quickly.
The PowerFlex 7000 drive can be used with either induction
(asynchronous) or synchronous motors. Synchronous motor drives
are identical to induction motor drives except for the addition of a
current regulated field supply to the synchronous drive. The features
that are unique to a synchronous motor drive are confined to the flux
control function and the encoder option.

1-2 Functional Description
7000-TD002A-EN-P – September 2007
Description of Operation A complete block diagram of the PF7000 control circuit is shown in
Figure 1.1. The major blocks are described in the following sections.
Line
Protection
Rectifier DCLink
inductor
Line filter
cap
Inverter Motor filter
cap Motor
Voltage
Motor Current Speed
Command
Speed
Reference
Machine side
feedbackand
gating
Alpha
Inverter
Alpha
Rectifier
Line side feedback
and gating
LineVoltage
ACLine
Reactor
Line
Current
Faults
InvTorque
CurCmd
Inv Flux
CurCmd
FluxRange
Machine
Protection
Sync
Transfer
Speed
Control
Stator freq
Slipfreq
FluxFeedback
Speed Feedback
Flux
Control
Faults
Tach
Feedback
Source
Motor
Current
Control Motor
Model
IdcFeedback
Figure 1.1 – Functional Block Diagram of PF 7000 control system

Functional Description 1-3
7000-TD002A-EN-P – September 2007
Speed Command The function of Speed Command block is to select one of the 10
possible speed command inputs. Parameter Speed Ref Select (7) in
conjunction with Local/Remote selector switch is used to define the
speed command input Speed Command In (276). When the selector
switch is in Local position, the default speed command is the Analog
Speed Potentiometer typically mounted on the LV panel. When the
selector switch is in Remote position, the parameter Speed Ref Select
defines the source of speed command. The options available are:
Local ( Speed Potentiometer)
3 DPI commands ( DPIAdapter1, DPIAdapter2, DPIAdapter5)
2 Analog Inputs configured either for 0-10V or 4-20mA (Analog
Inp1, Analog Inp2)
3 Preset speeds (Preset Spd 1, Preset Spd 2, Preset Spd 3)
1 Preset Jog
In addition, the speed command can come from a built in PID
controller. 
The above speed commands are used when the drive is in Normal
mode of operation. However PF7000 has many special modes of
operation e.g. test modes or auto-tuning for which different speed
commands are selected. Table 1.A summarizes the speed command
during these special modes.
Table 1.A – Speed Commands for special operating modes of PF7000
Special operating modes of PF7000 Speed Command In(276)
DC test mode Rated line frequency
Open Circuit Rated Line Freq (17)
Open Loop 0.1 x Rated Line Freq (17)
Rs autotune 2Hz
Ls autotune Rated Line Freq (17)
Flux Reg autotune Autotune Spd Cmd (213)
Speed Reg autotune Autotune Spd Cmd (213)
Sync transfer requested Bypass Frequency (159)
The selected Speed Command In is clamped to a minimum and a
maximum level by parameter Speed Cmd Max (290) and Speed Cmd
Min (293) to give Speed Command (277). The maximum value of
Speed Command cannot be greater than 125% of Base Speed (98).
Note: Contact the factory for applications that require output
frequencies greater than 125% of the motor base speed.
Contact factory for the availability of this feature.

1-4 Functional Description
7000-TD002A-EN-P – September 2007
Speed Command (cont.) Three skip speeds Skip Speed 1(49), Skip Speed 2 (50), Skip Speed 3
(51) are provided to prevent the drive from continuously operating at
a certain speed. This feature is sometimes needed to avoid mechanical
vibrations occurring in a drive system at certain speeds. The skip
speed zone around each Skip Speed is specified by the parameter
Skip Speed Band1 (53), Skip Speed Band2 (54), Skip Speed Band3
(55) If the desired Speed Command lies in a given skip speed zone,
the Speed Command is clamped to the lowest value in the zone.
Example
If Skip Speed 1 is 45 Hz with Skip Speed Band1 as 1 Hz, then the
skip speed range extends from 44.5 Hz to 45.5 Hz. If the desired
speed command is set to 45 Hz, then the drive will avoid this speed
and run at 44.5 Hz.
The final stage in processing the command is the whether the drive
has been requested to run forward or reverse. The sign is changed if
reverse rotation is selected. The Speed Command is set to zero if the
drive is stopped.
Speed Reference The function of the Speed Reference block is to determine the Speed
Reference (278) from the desired Speed Command (277). PF7000
provides two options:
•S-curve
•Linear Ramp
To select, S curve a non-zero value of S curve Percent (475) is
selected. Using parameter S curve Acc1 (481), the drive
automatically calculates the linear and the non-linear portions of the
S curve as shown in Figure 1.2. Following example shows how to
use S curve parameters:
Example
If S curve Accel 1 is set for 20 sec with 20% in S curve Percent, then
the total acceleration time is increased by 0.2 x 20 = 4 seconds. The
total acceleration time will now be 24 seconds with 4 seconds in the
non-linear portion of the S curve. Since the curve is symmetrical,
each of the segments will be of 2 seconds duration.
The parameters for deceleration are calculated using parameter S curve
Decel 1 (479) and S curve Percent (475) and shown in Figure 1.2.
Linear Ramp is enabled if the S curve Percent is set to zero.
Independent four section ramps are provided for acceleration and
deceleration. The ramp is specified by 4 Ramp Speeds, 4 Accel and
Decel times and is shown in Figure 1.3.

Functional Description 1-5
7000-TD002A-EN-P – September 2007
Linear Portion Non-Linear
Portion
Non-Linear
Portion
S Curve Acc1
(481)
0.005*
S Curve Acc1
*S Curve
Percent S Curve Dec1
(479)
Linear Portion
Non-Linear
Portion Non-Linear Portion
0.005*
S Curve Acc1
*S Curve
Percent
0.005*
S Curve Dec1
*S Curve
Percent
0.005*
S Curve Dec1
*S Curve
Percent
Linear Portion Non-Linear
Portion
Non-Linear
Portion
S Curve Acc1
(481)
0.005*
S Curve Acc1
*S Curve
Percent S Curve Dec1
(479)
Linear Portion
Non-Linear
Portion Non-Linear Portion
0.005*
S Curve Acc1
*S Curve
Percent
0.005*
S Curve Dec1
*S Curve
Percent
0.005*
S Curve Dec1
*S Curve
Percent
Figure 1.2 – Speed Reference: S-curve
Ramp Speed1
(73)
Ramp Speed4
(76)
Ramp Speed3
(75)
Ramp Speed2
(74)
Accel
Time1
(65)
Accel
Time4
(68)
Accel
Time3
(67)
Accel
Time2
(66)
Decel
Time1
(69)
Decel
Time2
(70)
Decel
Time3
(71)
Decel
Time4
(72)
Ramp Speed1
(73)
Ramp Speed4
(76)
Ramp Speed3
(75)
Ramp Speed2
(74)
Accel
Time1
(65)
Accel
Time4
(68)
Accel
Time3
(67)
Accel
Time2
(66)
Decel
Time1
(69)
Decel
Time2
(70)
Decel
Time3
(71)
Decel
Time4
(72)
Figure 1.3 – Speed Reference: Linear Ramp

1-6 Functional Description
7000-TD002A-EN-P – September 2007
Speed Control The function of the speed control block is to determine the torque-
producing component (Isq) of the stator current (Is). The inputs to the
block are the Speed Reference (278) from the speed ramp and the
Stator Frequency (448) and Slip Frequency (343) from the motor
model. If drive is installed with an optional tachometer, then the
motor speed is determined by counting the tach pulses.
In Sensorless operation, the Slip Frequency is subtracted from the
Stator Frequency and filtered to determine the Speed Feedback
(289). In Pulse Tach mode, the speed is determined directly by using
Tach Feedback (349). The Speed Feedback is subtracted from the
Speed Reference to determine the Speed Error (472) which is
processed by the speed PI regulator. The gains of the regulator are
based on the Total Inertia (82) of the system and the desired Spdreg
Bandwidth (81). The output of the speed regulator is the Torque
Reference (291) whose rate of change is limited by Trq Rate Limit
(83). The calculated Torque Reference is divided by the Flux
Reference (305) and motor constant to determine the torque
component of the stator current MtrTorque CurCmd (292). To
calculate the torque producing current supplied by the inverter
InvTorque CurCmd (294), the current supplied by the motor filter
capacitor in torque production (orthogonal to motor flux) is
calculated and subtracted from MtrTorque CurCmd.
In Sensorless mode, the drive uses TrqCmd0 Sensrlss (86) and
TrqCmd1 Sensrlss (87) for an open loop start up. At frequencies
greater than 3Hz, the drive enables the speed loop and disables the
open loop start mode. In Pulse Tach mode, the drive is always in
closed loop. The maximum torque a drive can deliver in motoring
mode is determined by Trq Lmt Motoring (84). In regenerative mode
the torque is limited to Trq Lmt Braking (85). It should be noted that
at speeds above the Base Speed (98), the motor torque capability is
de-rated and varies in inverse proportion to the speed (constant
power range).
Depending open the application, a drive can be configured in
different torque control modes by setting the parameter Trq Control
Mode (90). E.g. in stand-alone drives the parameter is set as Speed
Reg allowing the drive to be in speed control mode and regulating
the torque in the motor. In torque follower applications like
conveyors, one of the drives (Master) is set in Speed Reg mode
which enables the speed regulator while the other drives (torque
followers) are set in Trq Cmd External mode. The torque reference
produced by the Master drive is then passed on to the torque follower
drives by Trq Cmd External (91). Figure 1.4 shows other various
modes of operation.

Functional Description 1-7
7000-TD002A-EN-P – September 2007
3Hz
+
-
+
S
T
+
-
4
3
0
(OL ,S)
1,3,4,5(S,T)
2,5 (S,T)
0
Torque Referenc
e
(291)
Mtr Torque
CurCmd
(292)
OPEN LOOPSTART
(OL)
TORQUE
CONTROL
MODE TORQUE
LIMIT
TrqCmd0SensrLss(86)
TrqCmd1SensrLss(87)
Speed Reference (278)
TRQ RATE
LIMIT
Trq
Control
Mode
(90)
Trq Rate
Limit(83)
Flux
Reference
(305)
Mtr Flux
CurCmd
(310)
Trq Lmt
Motoring
(84)
Trq Lmt
Braking
(85)
R Stator (129) InvTorque
CurCmd
(294)
CAP
CURRENT
CALCULATOR
Motor Filter Cap (128)
LTotalLeakage (130)
Trq Control Mode (90) 0: Zero Torque 1: Speed Reg 2: Ext Trq Cmd 3: Spd Trq Pos 4: Spd Trq Neg 5: SpdSum
Spdreg
Bandwidth
(81)
Speed Fbk
Mode
(89)
Trq Control
Mode
(90)
Trq Cmd External (91)
Spdreg
Bandwidth
(81)
Total
Inertia
(82)
SPEED
REGULATOR
OL
Speed Error
(472)
Speed
Feedback
(289)
SPEED
FEEDBACK
FILTER
Speed Fbk Mode (89) S: Sensorless T: Pulse Tach
Speed Fbk
Filter (110)
Speed Fbk
Mode (89)
SPEED MODE
SELECT
Synch Reg Output (298)
Tack Feedback (349)
Slip Frequency
(343)
Stator Freq (448)
SCurvePercent
(475)
Speed Command In (276) SPEED
REFERENCE
Speed Cmd
Min
(293)
Speed Cmd
Max
(290)
Figure 1.4 – Speed Control

1-8 Functional Description
7000-TD002A-EN-P – September 2007
Flux Control The function of the flux control block (Figure 1.5) is to determine the
magnetizing component (Isd) of the stator current (Is) needed to
maintain the desired flux profile in the motor. The inputs are Flux
Feedback (306) and Stator Freq (448) from the motor model, Speed
Feedback (289) and Torque Reference (291) from the speed control
block and the measured voltage at the input of the rectifier, Rec
Input Volt (696).
The Flux Feedback is subtracted from the Flux Reference (305) to
determine the Flux Error (307), which is the input to the flux PI
regulator. The gains are determined from desired Flxreg Bandwidth
(97) and motor parameters T Rotor (132) and Lm Rated (131). The
output of the flux regulator is FluxCurRegulator (309). An open loop
estimate of the magnetizing current FluxCur Feedfwd (308) is
determined by dividing the Flux Reference by parameter Lm Rated.
FluxCur Feedfwd and FluxCurRegulator are added to produce Mtr
Flux CurCmd (310) which is the magnetizing component of the
stator current command. To calculate the magnetizing current
supplied by the inverter Inv Flux CurCmd (312), the current supplied
by the motor filter capacitor in magnetizing is calculated and
subtracted from Mtr Flux CurCmd. It should be noted that as the
motor speed increases, Inv Flux CurCmd decreases. This is because
as the motor voltage increases more of the magnetizing current
requirement of the motor is met by the capacitor. At resonant point,
Inv Flux CurCmd is nearly zero and becomes negative at speeds
above resonance. InvTorque CurCmd (from Speed Control block)
and Inv Flux CurCmd are then passed to the Current Control block to
determine the dc link current reference (Idc Reference) and the firing
angles of the two converters (Alpha Rectifier and Alpha Inverter).
The flux profile in the drive is adjusted by the parameters Flx Cmd
No Load (103) and FlxCmd RatedLoad (100). Using these
parameters, Flux Reference is adjusted linearly with the desired
Torque Reference. At light loads motor flux is decreased allowing
reduction in losses while full flux is produced at rated load. The
maximum flux reference is limited to Flux Cmd Limit (623). This
limit is dependent on the Rec Input Volt and the motor speed (Speed
Feedback). If the drive operates at reduced line voltage, then Flux
Reference is reduced. Also if the motor is running above the Base
Speed, the flux profile is made inversely proportional to the speed of
the motor resulting in the field weakening or the constant power
mode of operation of the drive. This is accompanied by a decrease in
the motor torque capability.

Functional Description 1-9
7000-TD002A-EN-P – September 2007
-
++
+1.0
-1.0
FluxCur Feedfwd
(308)
EXCITATION
CURRENT
LIMIT
MtrFlux CurCmd
(310)
Stator
Frequency
(448)
InvFluxCurCmd
(312)
CAPCURRENT
CALCULATOR
MtrTorque
CurCmd
(292)
Motor Filter Cap (128)
LTotal Leakage (130)
R Stator (129)
Flxreg
Band width
(97)
T Rotor (132)
Lm Rated
(131)
Flux
Feedback
(306)
Flux
Reference
(305)
FLUX
LIMIT
FluxError
(307)
Base
Speed
(98)
FlxCmd Rated Load (100)
Torque Reference (291)
Speed
Feedback
(289)
FlxCmd No Load (103)
RecInputVolt
(696)
Rated Line
Volt (18)
Rated Motor
Volt (22)
FLUX
COMMAND
LIMIT
FluxCmd Limit
(623) Lm Rated
(131)
FluxCur
Regulator
(309)
FLUX
REGULATOR
Figure 1.5 – Flux Control

1-10 Functional Description
7000-TD002A-EN-P – September 2007
Flux Control for Synchronous
Motor 
Most of the magnetization for a synchronous motor is supplied by
the rotor field winding, unlike an induction motor where all of the
magnetizing current is supplied through the stator. However, control
of the motor flux through the field current is very slow because of
the large time constant of the dc field winding and the current and
voltage limitations of the field supply. To obtain sufficiently fast
response from the flux regulator the magnetizing current is split into
transient and steady state components, with the steady state
component supplied through the rotor and the transient component
through the stator.
The additions to the flux control required for synchronous machines
are shown in the block diagram (Figure 1.6). The portion of the
motor filter capacitor current supplied by the drive is then added to
determine Inv Flux CurCmd, which is the magnetizing component of
the dc link current command.
Parameter Icd Command Gain (107) determines how the motor filter
capacitor current is split between the motor and the drive. When this
parameter is set to its minimum value of 0.0, all the capacitor current
is supplied by the drive. The line current is higher than the motor
current and the motor operates at approximately unity power factor.
When this parameter is set to its maximum value of 1.0, the motor
supplies all the capacitor current. The line current is less than the
motor current and the motor operates at a lagging power factor with
reduced field current.
Contact factory for the availability of synchronous motor control.

Functional Description 1-11
7000-TD002A-EN-P – September 2007
-
+
+
+-
+
InvFlux CurCmd
(312)
Field CurCmd
(314)
Lmd
(418)
LmRated
(131)
Field Bandwidth
(106)
LOW PASS
FILTER
Mtr Flux CurCmd
(131)
Motor Filter
Cap (128)
LTotal Leakage
(130)
Lm Rated
(131)
CAPCURRENT
CALCULATOR
Stator
Frequency
(448)
Flux
Reference
(305)
Icd Command
Gain (107)
Figure 1.6 – Flux Control for Synchronous Motor

1-12 Functional Description
7000-TD002A-EN-P – September 2007
Current Control The function of the current control block (Figure 1.7) is to determine
the firing angles for the converters Alpha Rectifer (327) and Alpha
Inverter (328). The inputs are the torque (InvTorque CurCmd) and
flux producing (Inv Flux CurCmd) components of the dc link current
command from the speed control and flux control blocks respectively,
and the measured dc link current Idc Feedback (322).
The square root of the sum of the squares of Inv Flux CurCmd and
InvTorque CurCmd determines the dc link current reference Idc
Reference (321). This is subtracted from the measured dc current
feedback is subtracted to determine Idc Error (323). This is
processed by the current regulator to produce Vdc Error (332). To
effectively control the dc link current an estimate of the motor side
dc link voltage is done to calculate Vdc Feedfwd (333) which is
added to Vdc Error to produce the reference voltage for the line side
converter Vdc Reference (326). The line converter firing angle is the
inverse cosine of Vdc Reference. The machine converter firing angle
is determined by taking the inverse tangent of the ratio of Inv Flux
CurCmd to the InvTorque CurCmd. The quadrant of operation is
adjusted based on the signs of the current commands.

Functional Description 1-13
7000-TD002A-EN-P – September 2007
InvFlux
CurCmd
(312)
Alpha Inverter
(328)
Curreg
Bandwidth
(113)
DCLnk
Inductance
(27)
DC LINK
CURRENT
REGULATOR
T DC link
(115)
Idc Reference
(321) Vdc Reference
(326)
Alpha Rectifier
(327)
InvTorque
CurCmd
(294)
Idc feedback
(322)
+-
Idc Error
(323)
Stator Voltage
(344)
Line Voltage pu
(135)
Alpha Inverter
(328)
+
+
Vdc Error
(332)
FEEDFORWARD
FILTER
Advance Limit
Feedforward Fil
(502)
Vdc Feedfwd
(333)
tan-1
cos
- 1cos-1
x2+y2
Retard Limit
Figure 1.7 – Current Control

1-14 Functional Description
7000-TD002A-EN-P – September 2007
Line Converter Feedback The function of the line converter feedback block is to process (scale
and filter) the liner side voltage and current feedback signals to the
form required by the drive control software. The circuitry for
realizing this is built in the Analog Control Board (ACB).
The first Voltage Sensing Board (VSB) provides three line voltage
feedback signals (V2u, V2v, V2w), the second VSB provides two dc
(VL+, VL-) and one line side filter capacitor voltages referenced to
ground. The three line-to-ground voltages are subtracted from each
other to produce the three line-to-line voltages (V2uv, V2vw, V2wu). Two
of those line voltages (V2uv, V2vw) are filtered and sampled by
software for synchronization and protection. The three line voltages
are used to find the peak input voltage (V2-pk). This value is then
compared with trip setting (Vltrp) for instantaneous hardware ac over
voltage protection. In PWM drives, the neutral point of the line filter
capacitor is measured (Vn1) and used for line side neutral over
voltage protection. The two dc voltages are subtracted to determine
the line side dc link voltage (Vdcr1), which is then sampled by the
drive.
Current transformers (CT) in two of the ac input lines provide the
input line current feedback (I2u, I2w). Inverting and adding the two
current feedback signals reproduces the current in the remaining
phase. A Hall Effect Current Sensor (HECS) is used for monitoring
the dc link current and used for hardware overcurrent protection. In
addition the average value of the dc link current feedback is
measured using a V-f converter and used by the dc link current
controller to calculate the firing angle for the rectifier.
The preceding description applies to 6-SCR and PWM rectifier
options. For drives with the 18 pulse front-end, another VSB is daisy
chained with the first one providing additional six line-to-ground
voltages from the slave bridges. The slave 1 voltages are monitored
using (V3uv, V3vw, V3wu) while slave 2 voltage are monitored using
(V4uv, V4vw, V4wu). In addition current feedback from slave bridges I3u,
I3w and I4u, I4w are also brought in for protection. As in 6-pulse drives,
inverting and adding the two current feedback signals reproduces the
current in the remaining phase. Also for 18-pulse drives, the three ac
line-to-ground voltages are summed together to determine the neutral
to ground voltage on the input transformer.

Functional Description 1-15
7000-TD002A-EN-P – September 2007
Machine Converter Feedback The function of the machine converter feedback block is to process
(scale and filter) the motor side voltage and current feedback signals
to the form required by the drive control software. The circuitry for
realizing this is built in the Analog Control Board (ACB).
The first VSB provides three motor voltage feedback signals (Vu, Vv,
Vw), the second VSB provides two dc (VM+, VM-) and one machine
side filter capacitor neutral voltage referenced to ground. The motor
line-to-ground voltages are subtracted from each other to produce the
three motor line-to-line voltages (Vuv, Vvw, Vwu). Two of those
voltages (Vuv, Vvw ) are filtered and sampled by software for
synchronization and protection. The three line voltages are used to
find peak voltage (V_pk). This value is then compared with trip setting
(Vmtrp) for instantaneous hardware ac over voltage protection. The
motor line-to-ground voltages are summed to determine the motor
neutral-to-ground voltage (Vzs) and is used for motor neutral over
voltage protection. In addition, the neutral point of the motor filter
capacitor is measured (Vn) and used for motor side neutral over
voltage protection. The two dc voltages are subtracted to determine
the machine side dc link voltage (Vdci1), which is sampled by the
drive.
Two Hall Effect Current Sensor (HECS) provide stator current
feedback from two of the motor phases (Iu, Iw). Inverting and adding
the two current feedback signals reproduces the current in the
remaining phase. The drive control software uses the sampled
voltages and currents to determine the motor flux and uses it for
synchronization.
For drives with Synchronous Transfer option, an additional VSB is
used for sensing three line-to-line bypass voltages ( Vuvs, Vvws, Vwus).
Two of these (Vuvs, Vvws) are further filtered and sampled by the
software for synchronizing the drive output voltage to the bypass
voltage.
If drive is installed with an optional tachometer, the board is plugged
into the J28. The motor speed is then determined by counting the
tach pulses in the FPGA on the DPM.

1-16 Functional Description
7000-TD002A-EN-P – September 2007
Motor Model The function of the motor model block (Figure 1.8) is to determine
the rotor flux position (Flux Angle), flux feedback (Flux Feedback),
applied stator frequency (Stator Freq), slip frequency (Slip
Frequency) and motor operating variables like stator current (Stator
Current), stator voltage (Stator Voltage), torque (MtrAirGap
Torque), power (MotorAirGap Power) and power factor (Mtr Pwr
Factor).
The PowerFlex 7000 uses Rotor Flux oriented control to achieve
independent control of motor flux and torque. This is achieved by
synchronizing the machine converter gating to Flux Angle. To
determine the flux feedback, stator frequency and the synchronizing
reference frame the drive uses either the Voltage or the Current
model. For speeds greater than 3Hz, the drive uses the voltage model
(from measured motor voltage and current) to calculate the Flxfbk
VoltModel, and StatFreq VoltModel. Below 3Hz, the drive uses the
current model to calculate Flxfbk CurModel, and StatFreq
CurModel. The current model is based on indirect vector control and
uses the d-q components of stator current along with motor
parameters T Rotor and Lm Rated. Based on the operating speed of
the drive and the speed feedback mode (Sensorless or Pulse Tach), a
flux select algorithm determines the model to be used. Motor model
also calculates the Slip Frequency which is used in the calculation of
the motor speed (Speed Control) in Sensorless mode and for
determining the rotor flux position in Pulse Tach mode.
The synchronously rotating frame (Flux Angle) is used in
transforming the measured motor currents and voltages into d-q
components. The direct axis components are in phase with the rotor
flux, while the quadrature axis components are displaced 90 degrees
from the rotor flux. The stator current (Stator Current) and voltage
magnitudes (Stator Voltage) are calculated by taking the square root
of the sum of the squares of the respective d-q components. The
motor Torque is calculated by multiplying the Flux Feedback and Isq
with motor torque constant. Torque multiplied by the motor speed
gives the Mtr AirGap Power. Mtr Power Factor is determined as the
ratio of motor active power and the apparent power.