Research on Dead Zone Compensation Method Based on Offline Calibration

When the motor is driven, Dead zone time setting is necessary to avoid the straight-through of the upper and lower arms. The presence of a dead zone results in a voltage error between the voltage reference and the actual output voltage. This voltage error causes a fluctuation of the fundamental frequency of six times in the dq current, which affects the control performance of the motor. The traditional dead zone compensation method dead zone compensation value changes with the magnitude of the current waveform as a trapezoidal wave, and cannot reflect the nonlinear relationship between the current amplitude and the dead zone compensation value. This paper first analyzes the voltage error generated by the dead zone, indicating that the voltage error generated by the dead zone has a nonlinear relationship with the current amplitude. Then, a method based on offline identification is proposed to perform dead zone compensation. The method is offline to obtain the nonlinear relationship between the voltage error generated by the dead zone and the current amplitude, and then online to check the application. It has a voltage compensation value and a small current harmonic content. Finally, an experimental verification is performed. The experimental results show that after using this method, the dq current fluctuation and phase current harmonic content are greatly reduced, and the method is effective. The proposed method can be extended to other applications and has strong versatility.