How should the power ground and signal ground of EPS be separated?

In EPS (Electronic Power Controller), separating power ground and signal ground is crucial for controlling noise coupling and ensuring control accuracy. Power ground carries high current and high dv/dt noise, while signal ground requires extreme cleanliness. The purpose of separation is to prevent power ground noise from coupling to signal ground through common ground impedance.

Method: On the PCB layout, physically separate power ground (e.g., inverter bridge, DC-Link capacitor, input filter capacitor ground) and signal ground (e.g., control chip, op-amp, ADC, sampling resistor ground) into different copper areas. Then, connect them through a single, low-impedance point (usually the negative terminal of the DC-Link capacitor or the star ground of the main filter) to provide a path for quiescent and low-frequency currents while blocking the propagation of high-frequency noise. During separation, ensure that no signal lines cross the separation gap; they must be routed above the connection point or bridged using isolation devices.