Beijer Electronics AN-BEI-P2-050 - Manual (Page 7)

APPLICATION NOTE AN-BEI-P2-050 Date: 15/02/12
AN-BEI-P2-050 Open Loop Permanent Magnet Motor Control 7
Parameter P4-04 is set as a time (in ms). The smaller the time (integration time) the more responsive the drive
output, at the possible expensive of instability.
Small amounts of integral gain can have a significant effect on reaction times and stability of the speed controller.
General practice with tuning a PI system is to set the integral value (P4-04) to its highest possible setting (1.0 sec)
and tune the proportional value (P4-03) for optimum performance. When proportional gain has been set /
optimized then the integral gain (P4-04) can then be adjusted to eliminate steady state speed errors.
Changing Beijer Frequency Inverter P2 Torque Limits
Drive torque limits (proportionally related to current limits) are adjusted by parameters P4-07 (for drive motoring
torque), and P4-09 (for drive generating torque) respectively.
Generally PM motors have a significantly higher peak torque rating in relation to nominal torque (>200% of
nominal torque), such that these values do not normally need to be adjusted. Peak torque values are available
from the motor technical data sheet and if less that 200% of nominal torque these parameters can be adjusted to
provide peak torque to the motor.
PM Motor Troubleshooting:
Trip codes and fault diagnostic information is provided in the standard Beijer Frequency Inverter P2 manual. Below
is further troubleshooting information specific to PM motor control.
Symptom Solution / Advice
Cannot set P4-01 for PM motor Control PM motor access code not entered in P1-14. Value ‘201’ required.
Delay seen after drive enable There is an in-built delay after enable to magnetise and orientate the motor
shaft immediately after enable. Delay time is controlled by parameter P7-12.
See drive optimisation setting for optimal set-up.
Auto-tune failure See standard Beijer Frequency Inverter P2 P-2 user guide
Poor Torque Performance at low speed Some low speed current boost required. See Low speed boost phase in set
up section.
Too much current causing motor to heat up Check parameter P1-07, motor nominal voltage is set correctly
Check parameter P1-08, motor nominal current is set correctly
If operating for sustained time period at low speed check levels of boost
current applied (P7-14, and P7-15)
Motor Stalled Check motor connection
Check values entered into motor parameters (P1-07 to P1-10)
Check Auto-tune performed
Reduce the load
Increase acceleration / deceleration time
Increase drive / motor rating
Unstable motor speed Check switching frequency hasn’t been adjusted below recommended
minimum (16 kHz)
Check values entered into motor parameters (P1-07 to P1-10)
Check Auto-tune performed
Check appropriate tuning of speed loop controller, reduce gains as required
Poor motor dynamics, slow response times Check values entered into motor parameters (P1-07 to P1-10)
Check Auto-tune performed
Check appropriate tuning of speed loop controller, increase gains as
required