Compared with electrical or mechanic system, hydraulic system have the disadvantages of high fault frequency and difficulties to diagnosis, which have greatly effected battle effectiveness in warfare.

In a drive system of power transistor inverter-motor, not only can it be used in fine control of motor current waveform, phase, amplitude and frequency, but can also be used to sense, fault current.

When disconnected with external power grid due to certain fault, it will result in frequency collapse, and even leads to large-scale blackout owing to the active power imbalance.