Single-phase Half-bridge Inverter Research Articles

A Half-Bridge-Level Gate-Oxide Failure Online Detection Method Without Invading Converters for SiC MOSFETs

Half-bridge-level gate-oxide failure online detection is a basis of low failure rates for power converters with SiC MOSFETs. The conventional detection methods of gate-oxide failure usually invade gate driver boards or alter control strategies of power converters. A simple detection method of half-bridge-level gate-oxide failure is proposed by connecting half-bridge SiC MOSFETs and gate driver boards through the proposed circuit. The principles of the proposed circuit are solving difference between two on-state gate voltages in high-side and low-side SiC MOSFETs and solving difference between an on-state gate voltage of low-side SiC MOSFETs and a positive output voltage of low-side gate driver board. As a result, if either of the two absolute difference values is more than 10mV, the gate-oxide of half-bridge modules will be detected as failure. The half-bridge modules with gate-oxide failure can be replaced. The proposed circuit is validated by a case study on a single-phase half-bridge inverter. The proposed circuit does not invade gate driver boards and change control strategies of power converters. It can detect half-bridge gate-oxide failure caused by various working conditions.

Nonlinear control and stability analysis of single stage grid-connected photovoltaic systems

This work presents the control development of a single stage grid-connected photovoltaic (PV) system. The topology used by the PV system consists of two PV panels, a single-phase half-bridge inverter using two DC link capacitors, and an LCL filter in the grid side. The aim is to design a nonlinear controller to ensure simultaneously the following three objectives: (i) PV panels to provide their maximum power, (ii) balanced power exchange by regulating the DC link voltage, and (iii) power factor correction, i.e. grid current in phase with grid voltage. In order to fulfill these objectives, a multi-loop controller is designed by using back-stepping and Lyapunov approaches for the power factor correction objective and a filtered PI regulator to ensure the power balance between the grid and the PV panels. The controller performances are formally analyzed using an average large signal model. The performance of the proposed controller is shown by means of simulation results in MATLAB/SimPowerSystems environment.

Improvement of the mathematical model of single­phase half­bridge inverter in state­variable form

The mathematical model of the insulated-gate bipolar transistor in the IGBT module is improved due to the determination of analytical expressions for dynamic spurious capacitances of the device. The expressions are obtained by analytical differentiation of functions that approximate the dependence of the spurious capacitances of the transistor on the voltage between the collector and the emitter. The method of forming a mathematical model of the IGBT voltage inverter in the form of matrix differential equations of state in the Cauchy form and nonlinear equations is proposed. There are no restrictions on the number of transistors and the configuration of the circuit. The method is based on the matrix-topological method of electrical circuits analyzing. The application of this method is illustrated by the example of a single-phase half-bridge inverter with resistive load. The urgency of improving the mathematical model of the IGBT inverter is caused by the need to analyze the electrical safety of the state of the variable frequency circuit between the frequency converter and the motor. Existing models of frequency-controlled electric drives do not take into account a number of factors that significantly affect the accuracy of the simulation. Such factors include the dynamic nature of the IGBT spurious capacitances and the disconnection of one of the machine phases from the network during the dead time when switching adjacent power switches of the inverter. The obtained mathematical model differs from the well-known in advanced representation of separate elements by nonlinear differential equations and taking into account mutual influences. The proposed approach allows to investigate the high-frequency transient components of currents and voltages in electrical systems with semiconductor converters. This simplifies taking into account the recharging processes of the IGBT capacitances during a dead time when switching adjacent power switches in the model. The peculiarities of the IGBT inverter switching transients are revealed, in particular, the significant exceeding, more than twice, of the transistor current during opening the operating current at the end of the switching process.

Stability of FPGA Based Emulator for Half-Bridge Inverters Operated in Stand-Alone and Grid-Connected Modes

In this paper, we present stability of a field programmable gate array (FPGA)-based emulator for single-phase half-bridge inverters operated in stand-alone and grid connected modes. The emulator is not only sufficiently accurate to emulate the characteristic behavior of the inverters, but also is sufficiently simple to be implementable on limited FPGA resources. This implementation enables the inverter developers to evaluate the FPGA-based high-speed controller in the early process by a real-time simulator system, which is unable for offline commercial simulation software packages. The discrete-time models, which are implementable on FPGA, are derived by discretizing the continuous-time models of the inverter using the forward-difference method. The stability analysis for the proposed inverter models showed that the quite small values of internal resistances of the inductors may have a serious effect on the stability, which is one of the most important properties of the inverter mathematical model. The experimental results show that the proposed emulator yields voltage, and current responses, which match with that of the real inverter circuit almost exactly under the same digital controller. The results also show that the responses of the emulators are consistent with the stability analysis for the inverter models.

Multiplex transmission system for gate drive signals of inverter circuit using surface acoustic wave filters

We propose and fabricate a multiplexed transmission system based on frequency-division multiple access (FDMA) with surface acoustic wave (SAW) filters. SAW filters are suitable for use in wide-gap switching devices and multilevel inverters because of their capability to operate at high temperatures, good electrical isolation, low cost, and high reliability. Our proposed system reduces the number of electrical signal wires needed to control each switching device and eliminates the need for isolation circuits, simplifying the transmission system and gate drive circuits. We successfully controlled two switching devices with a single coaxial line and confirmed the operation of a single-phase half-bridge inverter at a supply voltage of 100 V, and the total delay time to control the switching devices was less than 2.5 µs. Our experimental results validated our proposed system.

고승압 듀얼 컨버터와 단상 하프 브릿지 인버터를 적용한 새로운 PCS

In this paper, a new PCS is proposed which is consisted of high boost dual converter and single phase half-bridge inverter. The proposed PCS is configured in parallel input / serial output, using two interleaved voltage doubler converter. Converter of the proposed PCS is distribute input current by configuring parallel input and reduced turn ratio of transformer by configuring serial output. Also, compositions of the inverter are composed of serial output capacitor of converter and half-bridge inverter. The dual converter and single phase half-bridge inverter is designed and characteristic of the new PCS is analysed. The system of the 1.5[kW] PCS is verified through an experimental about operation and stability.

Novel Ozone Generation Power Supply using a Topology of the PFC DC-DC Boost Converter and Single-phase Half-bridge Inverter

최근 들어 살균과 특수세정의 용도로 오존발생 장비들이 많은 주목을 받으면서, 오존발생 전원공급장치에 대한 연구들이 활발히 진행되고 있다. 따라서 본 논문에서는 PFC DC-DC 부스트 컨버터와 단상 하프브리지 인버터 구조를 이용하여 기존의 오존발생 전원공급장치에 비해 제어가 용이하고 시스템을 소형화한 새로운 오존발생 전원공급장치를 제안한다. 제안하는 전원공급장치는 펄스폭변조(PWM; Pulse-Width Modulation) 기법을 이용하여 전력반도체스위치를 스위칭하여 동작함으로써 시스템 손실을 최소화한다. 본 논문에서는 제안하는 전원공급장치의 각 부분의 동작원리를 모드별로 설명하고, 프로토타입 전원공급장치의 컴퓨터 시뮬레이션 결과와 실험결과를 통해 제안한 전원공급장치의 우수한 특성을 입증한다.

Experimental and Numerical Analysis of a Simple Core Loss Calculation for AC Filter Inductor in PWM DC-AC Inverters

This paper introduces a simple core loss calculation method for output filter inductor in pulse width modulation (PWM) DC-AC inverter. Amorphous C-core (AMCC-320) is used to analyze the core loss. In order to measure core loss of the output filter inductor and validate the proposed method, a single-phase half-bridge inverter and a calorimeter are used. By changing switching frequency and modulation index (MI) of the inverter, core loss of the AMCC-320 is measured with the lab-made calorimeter and the results are compared with calculated core loss. The proposed method can be easily extended to other core loss calculation of various converters.

A single-phase delta-modulated inverter for UPS applications

The performance characteristics of the rectangular wave delta modulation (RWDM) scheme for uninterruptible power supply (UPS) applications is investigated. Normalized characteristic curves that show the effect of various modulator parameters on the frequency spectrum of the inverter output voltage are obtained using discrete Fourier transform (DFT) and harmonic analysis techniques. The performance of a single-phase half-bridge inverter with an LC filter is discussed, and experimental results are provided to validate the predicted and simulated results. It is shown that the harmonic content of the inverter output waveform can be controlled through the control of the modulator parameters.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>