A Single-Phase Twin-Buck Inverter

Abstract

This paper proposes a simple single-phase twin-buck inverter to interface a DC source such as a renewable energy source to AC loads. It consisted of two identical buck converters with a sinusoidal duty ratio. The first converter produced a positive half cycle of a 50 Hz sinusoidal output voltage, and the second converter produced the negative one. Then, both of them are integrated using transistors Q3 and Q4. By shifting the phase angle of signals for triggering transistor Q3 and Q4 from a sinusoidal reference signal, the distortion around zero crossing was reduced. The computer simulation results show that the output voltage and current were sinusoidal with harmonic distortion of 1.12 and 0.49 % respectively. Keywords Buck converter Single-phase inverter ? 21.1 Introduction An inverter converts a DC voltage source or a DC current source to an AC voltage/current. It takes power from a DC source and sends the power to AC loads using power electronic devices. An inverter can be used to interface a renewable energy source such as PV panels to AC loads or a grid [1, 2]. A solar home system is one of the single-phase inverter application. Lamps and home appliances are connected to PV panels as well as to batteries through a single-phase inverter. There are many types of a single-phase inverter. The most common inverter, especially a voltage source inverter (VSI) is a single-stage bridge pulse-width-modulation (PWM) inverter [2-4]. It generally consists of four switches configured as a bridge with a filter. PWM signals trigger the switches to generate a sinusoidal AC waveform. Recently, a dual-buck full-bridge inverter [5, 6] as well as a two identical boost or buck-boost inverter [1] has been proposed. The main idea in H.H. Tumbelaka

A Simple Sinusoidal Buck Converter Working as A Single-Phase Grid-Connected Inverter

“…As a result, there is a slight phase difference between the sine wave and the square wave to trigger transistors. The TD block has been explained in [8] [9]. Without a phase shift, the inherent problem of zero-crossing distortion occurs.…”

“…The cascade topology [8] solves the problem by feeding phase-shifted PWM to different cascade units. In twin-buck inverter [9], a phase difference between VREF and square signals to trigger transistors is applied to mitigate the problem. 5 demonstrates the reference signal VREF and the carrier signals VTRI (1) and VTRI (2).…”

“…There is a shoot-through problem in high frequency switching transition between each leg's upper and lower transistors in a bridge VSI, which is generally overcome by a dead time mechanism. To mitigate the problem, a dual-buck inverter, and a two-boost (buck-boost) inverter [1][7] [8] as well as a twin-buck inverter [9] has been established.…”