Adaptive control of charging system based on online parameters identification

It is discussed that the changing of parameters in the battery pack model affects the control accuracy and dynamic response of the charging system, through establishing the peak current small signal model of the full-bridge converter and load battery packs´ model of the charging system. Moreover, the disadvantages of fixed parameters PID control are put forward. An online identification method is presented for battery pack charging parameters, which is based on a relay feedback system. According to the results of parameters identification, a self-tuning method is presented to regulate controller parameters in order to make the charging system obtain the specified crossover frequency and phase margin. As a consequence, the impact of input voltage fluctuations of chargers and characteristics change of the battery pack in charging process is mitigated for battery pack in charging process is mitigated for battery pack charging system stability and dynamic performance.