Research on Noise Optimization Control based on the New Dead Zone Compensation in Dual Motor Hybrid System

In a three-phase voltage source inverter, in order to prevent the direct short circuit of the upper and lower tubes of the bridge arm and ensure the normal operation of the inverter, microsecond-level dead time needs to be added when the power devices are turned on and off. However, due to the dead-time effect, slight distortion may occur in the inverter within the modulation period, and this distortion will eventually lead to harmonic components in the output current after accumulation, thereby generating torque ripple. Against the above background, implementing dead-time compensation strategies is very important. To compensate for the voltage error caused by the dead-time effect, current polarity determination is required first. Then, the dead time is compensated, thereby indirectly compensating for the voltage error caused by the dead-time effect. Regarding the dead-time compensation time, without changing the hardware, this paper proposes a solution to turn off the dead-time compensation function based on the noise evaluation standard in torque segments: that is, try to turn off the dead-time compensation in the range of the motor speed from 2200 to 2600 rpm and the requested motor torque from 100 Nm to 50 Nm; turn on the dead-time compensation above 50 Nm, which has a significant improvement in noise. The dead-time compensation is achieved by setting the dead time in segments through software, and the voltage of the controller is compensated from the dead-time effect to reduce current harmonics and thereby suppress torque ripple. This improves the NVH performance and reliability of vehicle operation.