Constant DC-Capacitor Voltage-Control-Based Strategy for Harmonics Compensation in Smart Charger for Electric Vehicles in Single-Phase Three-Wire Distribution Feeders with Reactive Power Control

摘要

This paper deals with harmonics compensation with reactive power control of the previously proposed constant dc-capacitor voltage-control (CDCVC)-based strategy in a smart charger (SC) for electric vehicles (EVs) in single-phase three-wire distribution feeders (SPTWDFs) under distorted load current conditions. For the control algorithm of SC, only the CDCVC block, which is typically used in grid-connected inverters including active power line conditioners, is used. No calculation blocks of the load-side fundamental active-reactive currents and harmonic currents are required. Thus, the authors offer a simplified harmonics compensation strategy with reactive power control for the SC in SPTWDFs. The basic principle of the CDCVC-based strategy is discussed in detail. Simulation and experimental results demonstrate that during battery-charging and battery-discharging operations in EVs, balanced and sinusoidal source currents with a predefined power factor of 0.9 on the source side, which is an acceptable value for Japanese domestic consumers, are achieved on the secondary side of the pole-mounted distribution transformer using the CDCVC-based algorithm. Simulation and experimental results also demonstrate that controlling the reactive power on the source side can reduce the capacity of the SC.