Among them, the control circuit is

Among them, the control circuit is isolated from the main power circuit, and there is a large current change in the main power circuit. When the switch is operated, the current rises or falls, which will emit electromagnetic interference with different frequencies, including conducted interference and radiated interference. In order to avoid the adverse effects of these interference signals on the control circuit, and make the control circuit detect the wrong signal and make wrong operation, the main circuit and the control circuit must be isolated and shielded.Isolation used in this design includes electromagnetic transformer isolation used in driving module, Hall element isolation used in sampling module, photoelectric isolation used in CAN transceiver, switch value and temperature acquisition signal in communication part, which can protect hardware control circuit. In terms of shielding, first of all, we should pay attention to good floor laying when wiring three modules; Secondly, it is necessary to increase reasonable filter capacitors. The working frequency range of filter capacitors with different materials and different capacities is different. Generally, the smaller the capacitance, the more high-frequency interference signals can be filtered; Finally, during installation, it should be noted that the control board should be as far away from the main power module as possible, and the control circuit can be separated by a metal baffle.