Fast True RMS Algorithm Using in the High-Voltage General Inverter

The high-voltage general inverter which has the advantage of the structure， has become the key equipment to saving energy in recent years. The inverter output current is the key variable of overload protection, over current protection and V/F control compensation, so the real-time accurate measurement of its RMS is extremely important. In this paper, the output current signals preprocess by hardware filter firstly, and then find the RMS of the current signal in the period of the waveform. Meanwhile, this algorithm belong to true RMS algorithm category, which suitable for testing harmonic current signal, and can avoid mean filter to reduce the computation time. By using this algorithm, the inverter control system provides accurate reference for overload protection reduces the systematic disoperation rate and sets the more accurate security allowance to ensure the safe operation of equipment.