Motor drive adaptation
A method and apparatus for the adaptation of a motor drive system is described. The method includes applying a small signal frequency sweep to a motor drive system wherein the motor drive system includes an inverter, an output filter (e.g. a sine filter) and a motor, acquiring frequency response data in response to said frequency sweep and setting parameters of the motor drive system depending on the acquired frequency response data.
1. A method comprising:
applying a small signal frequency sweep to a motor drive system wherein the motor drive system includes an inverter, an output filter and a motor;
acquiring frequency response data in response to said frequency sweep in order to determine resonances in the motor drive system; and
setting parameters of the motor drive system depending on the acquired frequency response data;
wherein applying the small signal frequency sweep comprises applying a voltage signal to the motor.
2. The method as claimed in claim 1 , wherein the voltage signal is a low voltage magnitude signal applied to the motor over a frequency range.
3. The method as claimed in claim 1 , wherein said acquired frequency response data comprises current data as a function of frequency resulting from the applied frequency sweep.
4. The method as claimed in claim 1 , wherein:
applying the small signal frequency sweep comprises applying multiple small signal frequency sweeps at different DC offset levels; and
acquiring frequency response data comprises acquiring frequency response data for each of said multiple small signal frequency sweeps.
5. The method as claimed in claim 1 , further comprising:
applying a DC magnetising pulse and repeating said frequency sweep applying and frequency response data acquiring steps.
6. The method as claimed in claim 1 , further comprising repeating said frequency sweep applying and frequency response data acquiring steps periodically.
7. The method as claimed in claim 6 , further comprising determining whether a change in said frequency response data is indicative of a significant performance change.
8. The method as claimed in claim 1 , wherein said parameters include one or more of a minimum, an optimum and a maximum switching frequency of said inverter.
9. The method as claimed in claim 1 , wherein said output filter is a sine filter.
10. A motor drive system comprising an inverter stage, a control module and an output filter, wherein the control module is configured to set parameters of the motor drive system depending on a measured resonance frequency of the motor drive system, wherein the resonance frequency is measured in response to applying a small signal frequency sweep to the motor drive system, and wherein applying the small signal frequency sweep comprises applying a voltage signal to the motor.
11. The motor drive system as claimed in claim 10 , wherein the small signal frequency sweep is applied under the control of said control module.
12. The motor drive system as claimed in claim 10 , further comprising a cable connecting an output of the inverter stage to a motor.
13. The motor drive system as claimed in claim 10 , wherein said parameters include one or more of a minimum, an optimum and a maximum switching frequency of said inverter stage.
14. The motor drive system as claimed in claim 10 , wherein said output filter is a sine filter.
15. A control method, comprising:
applying a small signal frequency sweep to a motor drive system, the motor drive system including an inverter, an output filter and a motor;
acquiring frequency response data in response to said frequency sweep in order to determine resonances in the motor drive system; and
setting parameters of the motor drive system depending on the acquired frequency response data;
wherein applying the small signal frequency sweep comprises applying a voltage signal to the motor.
16. The method as claimed in claim 2 , wherein said acquired frequency response data comprises current data as a function of frequency resulting from the applied frequency sweep.
17. The method as claimed in claim 2 , wherein:
applying the small signal frequency sweep comprises applying multiple small signal frequency sweeps at different DC offset levels; and
acquiring frequency response data comprises acquiring frequency response data for each of said multiple small signal frequency sweeps.
18. The method as claimed in claim 3 , wherein:
applying the small signal frequency sweep comprises applying multiple small signal frequency sweeps at different DC offset levels; and
acquiring frequency response data comprises acquiring frequency response data for each of said multiple small signal frequency sweeps.
19. The method as claimed in claim 2 , further comprising:
applying a DC magnetising pulse and repeating said frequency sweep applying and frequency response data acquiring steps.
20. The method as claimed in claim 3 , further comprising:
applying a DC magnetising pulse and repeating said frequency sweep applying and frequency response data acquiring steps.
21. The method as claimed in claim 8 , wherein the optimum switching frequency is set at a predetermined multiple of the determined resonance frequency.
22. The motor drive system as claimed in claim 13 , wherein the optimum switching frequency is set at a predetermined multiple of the determined resonance frequency.
23. The control method as claimed in claim 15 , wherein said parameters include one or more of a minimum, an optimum and a maximum switching frequency of said inverter, wherein the optimum switching frequency is set at a predetermined multiple of the determined resonance frequency.