A Novel Variable DC-Link Voltage Control Method for PMSM Driven by Quasi-Z-Source Inverter

Abstract

Variable dc-link voltage control methods can effectively improve the operation efficiency of the permanent magnet synchronous motor (PMSM) drive system. At present, the reported variable dc-link voltage control methods applied in the PMSM driven by quasi-Z-source inverter (qZSI) are limited to analytical calculation methods (ACMs) based on system model. The ACMs demand measurement of qZSI’s input voltage and usually need a larger margin index due to the inaccurate model to calculate the reference dc-link voltage. To overcome the restriction, this paper proposes a novel variable dc-link voltage control method which can indirectly adjust dc-link voltage with an extra PI-regulator. Basic principle of the method is introduced and two design rules of the PI-regulator are illustrated. Besides, necessary conditions which need to be met when obtaining the feedback signal of the PI-regulator are analyzed. Finally, experiments are performed to validate the feasibility and effectiveness of the proposed method. In comparison with the ACMs, the proposed method gets rid of the dependence on an extra voltage sensor to measure the input voltage and can reserve less margin for the dc-link voltage, which contributes to less cost and higher efficiency of the drive system. Besides, the proposed method is easy and convenient to apply.

Index Terms

1.      Permanent magnet synchronous motor (PMSM)

2.      Quasi-Z-source inverter (qZSI)

3.      Variable dc-link voltage control

4.      Analytical calculation method (ACM)

Schematic Diagram:

Fig. 1 Schematic diagram of ACM-based variable dc-link voltage control

Expected Simulation Results:

Fig. 2 Waveforms of on-load speed variation experiment with MDVR adopted under (a) slope speed command (b) step speed command.

 

Fig. 3 Waveforms of torque variation experiment with MDVR adopted under constant speed.

Fig. 4 Waveforms of regeneration braking experiment with MDVR adopted.

Conclusion

 

To avoid the existing problems of the ACM-based variable dc-link voltage control method in qZSI-PMSM drive system, this paper proposes an MDVR-based variable dc-link voltage control method. The novel method can indirectly adjust the dc-link voltage to its minimum which can exactly meet the PMSM’s operation demand by using an extra PI-regulator to control the minimum duty cycle of zero vector in one output electrical cycle to be a small constant. In this paper, basic operation principle of the proposed method is introduced firstly and then two design rules of the PI-regulator are illustrated with examples. Further, some conditions that need to be met when obtaining the minimum duty cycle of zero vector are also analyzed. Finally, experiments are performed to validate the feasibility and effectiveness of the proposed method. The advantages of the proposed method can be concluded as follow.

(1) It gets rid of the dependence on input voltage and thus does not need an extra voltage sensor;

(2) It does not rely on drive system’s inaccurate model and thus can reserve less margin for the dc-link voltage, which contributes to higher system efficiency;

(3) It is simple and easy to apply.

References

 

[1] W. Deng, C. Xia, Y. Yan, Q. Geng, and T. Shi, “Online multi-parameter identification of surface-mounted PMSM considering inverter disturbance voltage,” IEEE Trans. Energy Convers., vol. 32, no. 1, pp. 202–212, Mar. 2017.

[2] Z. Zhou, C. Xia, Y. Yan, Z. Wang, and T. Shi, “Disturbances attenuation of permanent magnet synchronous motor drives using cascaded predictive-integral-resonant controllers,” IEEE Trans. Power Electron., vol. 33, no. 2, pp. 1514–1527, Feb. 2018.

[3] S. Tenner, S. Gunther, and W. Hofmann, “Loss minimization of electric drive systems using a dc/dc converter and an optimized battery voltage in automotive applications,” in Proc. IEEE VPPC, 2011, pp. 1-7.

[4] S. Tenner, S. Gunther, and W. Hofmann, “Loss minimization of electric drive systems using a Z-source inverter in automotive applications,” in Proc. EPE’13-ECCE Europe, 2013, pp. 1-8.

[5] W. Deng, Y. Zhao, and J. Wu, “Energy efficiency improvement via bus voltage control of inverter for electric vehicles,” IEEE Trans. Veh. Technol., vol. 66, no. 2, pp. 1063-1073, Feb. 2017.