Low Frequency Voltage Boost; Rated Rpm Auto-Tune; Stator Resistance; Maximum Switching Frequency - Control Techniques unidrive sp Advanced User's Manual

Parameter Keypad and Parameter
structure display x.00
5.15

Low frequency voltage boost

Drive modes Open-loop, Closed-loop vector
Bit SP
Coding
Range Open-loop, Closed-loop vector
Open-loop
Default
Closed-loop vector
Update rate Background read
The voltage boost is used in fixed boost mode and square law mode for Open-loop mode, and during the rotating auto-tune test in Closed-loop vector
mode.
5.16

Rated rpm auto-tune

Drive modes Closed-loop vector
Bit SP
Coding
Range Closed-loop vector
Default Closed-loop vector
Update rate Background read
The motor rated full load rpm parameter (Pr 5.08) in conjunction with the motor rated frequency parameter (Pr 5.06) defines the full load slip of the
motor. The slip is used in the motor model for closed-loop vector control. The full load slip of the motor varies with rotor resistance which can vary
significantly with motor temperature. When this parameter is set to 1 or 2 the drive can automatically sense if the value of slip defined by Pr 5.06 and
Pr 5.08 has been set incorrectly or has varied with motor temperature. If the value is incorrect Pr 5.08 is automatically adjusted. Pr 5.08 is not saved
at power-down, and so when the drive is powered-down and up again it will return to the last value saved by the user. If the new value is required at
the next power-up it must be saved by the user. Automatic optimisation is only enabled when the frequency is above rated frequency/8, and when the
load on the motor load rises above
correct values of stator resistance (Pr 5.17), transient inductance (Pr 5.24), stator inductance (Pr 5.25) and saturation breakpoints (Pr 5.29 and Pr
5.30) should be stored in the relevant parameters. Rated rpm auto-tune is not available if the drive is not using external position/speed feedback.
The gain of the optimiser, and hence the speed with which it converges, can be set at a normal low level when Pr 5.16 is set to 1. If this parameter is
set to 2 the gain is increased by a factor of 16 to give faster convergence.
5.17

Stator resistance

Drive modes Open-loop, Closed-loop vector, Servo
Bit SP
Coding
Range Open-loop, Closed-loop vector, Servo
Default Open-loop, Closed-loop vector, Servo
Second motor
Open-loop, Closed-loop vector, Servo
parameter
Update rate Background read
NOTE
From software version 1.07.00 onwards the maximum value of this parameter increased from 30 to 65 ohms to allow use of the autotune with very
small motors. rS trips will be seen with small motors with a higher resistance than 30 ohms per phase with earlier software versions.
5.18

Maximum switching frequency

Drive modes Open-loop, Closed-loop vector, Servo, Regen
Bit SP
Coding
Open-loop, Closed-loop vector, Servo,
Range
Regen
Open-loop, Closed-loop vector, Regen
Default ,
Servo
Update rate Background read
This parameter defines the required switching frequency. The drive may automatically reduce the actual switching frequency (without changing this
parameter) if the power stage becomes too hot. The switching frequency can reduce from 12kHz to 6kHz to 3kHz, or 16kHz to 8kHz to 4kHz. An
Unidrive SP Advanced User Guide
Issue Number: 7
Parameter Advanced parameter
description format descriptions
FI DE Txt VM DP ND
1
0.0 to 25.0 % of motor rated voltage
3.0
1.0
FI DE Txt VM DP ND
0 to 2
0
5
/ rated load. Optimisation is disabled again if the load falls below half rated load. For best optimisation results the
8
FI DE Txt VM DP ND
3
0.0 to 65.000 Ω
0.0
Pr 21.12
FI DE Txt VM DP ND
1
0 to 5 (3, 4, 6, 8, 12, 16 kHz)
0 (3 kHz)
2 (6 kHz)
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Serial comms
Macros
protocol
RA NC NV PT US RW BU
1 1
RA NC NV PT US RW BU
1 1
RA NC NV PT US RW BU
1 1 1
RA NC NV PT US RW BU
1 1 1
Electronic Feature look-
Performance
nameplate up table
PS
1
PS
PS
1
PS
1
Menu 5
115