Measuring Current in a Power Converter Using Fuzzy Automatic Gain Control

Abstract

The accuracy of current measurements can be increased by appropriate amplification of the signal to within the measurement range. Accurate current measurement is important for energy monitoring and in power converter control systems. Resistance and inductive current transducers are used to measure the major current in AC/DC power converters. The output value of the current transducer depends on the load motor, and changes across the whole measurement range. Modern current measurement circuits are equipped with operational amplifiers with constant or programmable gain. These circuits are not able to measure small input currents with high resolution. This article proposes a precise loop gain system that can be implemented with various algorithms. Computer analysis of various automatic gain control (AGC) systems proved the effectiveness of the Mamdani controller, which was implemented in an MCU (microprocessor). The proposed fuzzy controller continuously determines the value of the conversion factor. The system also enables high resolution measurements of the current emitted from small electric loads (≥1 A) when the electric motor is stationary.

Simulation optimal and design of 3-kW DC-DC converter for pure electric vehicles

“…Many scientific papers have studied power converters, 1–22 which include different circuit topologies, soft switching control methods, and transformer optimization methods. However, the output powers of power converters in these scientific papers were not large, and there have been no in-depth studies on the input voltage range.…”

“…Both experimental and simulation results indicated that the power converter that used their proposed method had better robustness. Dominikowski 19 proposed a fuzzy gain system with high accuracy to improve the measurement accuracy of power converters. The simulation results showed that the fuzzy controller was feasible.…”