Digital control of a unidirectional battery charger for electric vehicles

The digital control of a unidirectional battery charger of 3 kW for electric vehicles is presented. The selected electrical architecture consists of a two-stage topology composed of a rectifier for power factor correction followed by a converter that manages the charge of the battery. Both stages are based on three 1 kW interleaved converters. In particular, first stage cells are boost converters while the second stage cells are buck converters. The control of inductor currents has been obtained by applying discrete-time sliding mode control theory at constant switching frequency. An outer control loop is meant to regulate the DC-link capacitor voltage between both stages and another loop regulates the charge of the battery.