Taking electric vehicles as an example, most electric vehicles currently use AC motors, and the battery discharge or charge is direct current. When the car is in the braking or downhill state, the motor is in the power generation state. Alternating current through the rectification to the DC test to charge the battery, but due to the different operating states of electric vehicles, the rectified direct current will be pure in the larger fluctuations, such as the motor weak magnetic high-speed operation generated by the back electromotive force will be higher than the battery operating voltage. The common solutions I've learned are dual-purpose:
1 A simpler method is to add a filter circuit, such as an rlc circuit, between the battery and the rectifier bridge, which will greatly optimize the current waveform, reduce the current impact, and safely recover energy.
2 Connect the rectified current to the supercapacitor and store the recovered energy in the supercapacitor. The power density of supercapacitors is large, the number of charge and discharge is large, and the discharge process is controllable. For example, some new electric buses will use supercapacitors. In graduate school, academic knowledge is shallow, I hope the answer is useful to you.