Peng Fang-zen, Qian Zhao-ming
College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China.
J Zhejiang Univ Sci. 2003 Nov-Dec;4(6):658-65. doi: 10.1631/jzus.2003.0658.
Cascade multilevel inverters have been developed for electric utility applications. A cascade M-level inverter consists of (M-1)/2 H-bridges in which each bridge's dc voltage is supported by its own dc capacitor. The new inverter can: (1) generate almost sinusoidal waveform voltage while only switching one time per fundamental cycle; (2) dispense with multi-pulse inverters' transformers used in conventional utility interfaces and static var compensators; (3) enables direct parallel or series transformer-less connection to medium- and high-voltage power systems. In short, the cascade inverter is much more efficient and suitable for utility applications than traditional multi-pulse and pulse width modulation (PWM) inverters. The authors have experimentally demonstrated the superiority of the new inverter for power supply, (hybrid) electric vehicle (EV) motor drive, reactive power (var) and harmonic compensation. This paper summarizes the features, feasibility, and control schemes of the cascade inverter for utility applications including utility interface of renewable energy, voltage regulation, var compensation, and harmonic filtering in power systems. Analytical, simulated, and experimental results demonstrated the superiority of the new inverters.
级联多电平逆变器已被开发用于电力应用。一个级联M电平逆变器由(M-1)/2个H桥组成，其中每个桥的直流电压由其自身的直流电容器支撑。这种新型逆变器能够：(1) 在每个基波周期仅开关一次的情况下产生几乎正弦波形的电压；(2) 无需传统电力接口和静止无功补偿器中使用的多脉冲逆变器的变压器；(3) 能够直接与中高压电力系统进行无变压器的并联或串联连接。简而言之，级联逆变器比传统的多脉冲和脉宽调制(PWM)逆变器效率更高，更适合电力应用。作者已通过实验证明了这种新型逆变器在电源、(混合)电动汽车(EV)电机驱动、无功功率(var)和谐波补偿方面的优越性。本文总结了级联逆变器在电力应用中的特点、可行性和控制方案，包括可再生能源的电力接口、电压调节、无功补偿和电力系统中的谐波滤波。分析、仿真和实验结果证明了新型逆变器的优越性。
