Single-switch Inverter Research Articles

Thinned-out controlled IC MPPT algorithm for class E resonant inverter with PV system

In this study, maximum power extracted from photovoltaic (PV) panels was transferred to the load using the proposed thinned-out controlled class E resonant inverter. For the system, PV panels were used as a power source. A PV powered system was designed using single switch inverter. Maximum power point tracker (MPPT) controlled resonant inverter was conducted under varying solar irradiation conditions. The output power of the voltage-fed class E resonant inverter circuit was controlled in a wide range by using the thinned-out control method in a fixed switching frequency of 63 kHz. In the proposed method, power control was provided gradually without increasing switching losses significantly by achieving zero voltage switching (ZVS) condition. ZVS conditions were met in most periods when the solar irradiation was at high level and the number of the skipped pulses was low. As a result, soft switching was provided and the single switch inverter could operate with higher efficiency. Incremental conductance (IC) algorithm was used to track maximum power in PV panels and the tracking efficiency was obtained as above 99 % by the proposed novel thinned-out controlled IC MPPT algorithm. The proposed method shows that since electromagnetic interference and switching losses are reduced, the size of the circuit components is also reduced, and therefore there is a significant reduction in the circuit volume and the costs.

Multiparallel and Flexible Expansion of Single-Switch WPT Inverter by Magnetic Integration

Aiming at the problem that the single-switch inverter for wireless power transmission circuit cannot realize the parallel connection of three or more inverters, a scheme that can arbitrarily expand the number of parallel inverters by changing the circuit structure is proposed. In this article, the current sharing coil (InterCell Transformer) is used to share the current between the branches to improve the system's stability. By adding a current-increasing <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> resonant network, the output voltage can be adjusted more flexibly, and the system volume can be reduced by applying the principle of magnetic integration. Then, the complex frequency-domain model is innovatively used to accurately express the single-switch inverter circuit, which is conducive to the equivalent analysis of its various derived circuits. Finally, a parallel experimental prototype is built. When the output voltage is 164 V and the current is 11 A, the maximum efficiency is 92.1%. The experimental results show that the scheme is reasonable, feasible, and reliable.

Zero Voltage Switching Condition in Class-E Inverter for Capacitive Wireless Power Transfer Applications

This paper presents a complete design methodology of a Class-E inverter for capacitive wireless power transfer (CWPT) applications, focusing on the capacitance coupling influence. The CWPT has been investigated in this paper, because most of the literature refers to inductive power transfer (IWPT). However, CWPT in perspective can result in lower cost and higher reliability than IWPT, because it does not need coils and related shields. The Class-E inverter has been selected, because it is a single switch inverter with a grounded MOSFET source terminal, and this leads to low costs and a simple control strategy. The presented design procedure ensures both zero voltage switching (ZVS) and zero derivative switching (ZDS) conditions at an optimum coupling coefficient, thus enabling a high transmission and conversion efficiency. The novelties of the proposed method are that the output power is boosted higher than in previous papers available in the literature, the inverter is operated at a high conversion efficiency, and the equivalent impedance of the capacitive wireless power transfer circuit to operate in resonance is exploited. The power and the efficiency have been increased by operating the inverter at 100 kHz so that turn-off losses, as well as losses in inductor and capacitors, are reduced. The closed-form expressions for all the Class-E inverter voltage and currents waveforms are derived, and this allows for the understanding of the effects of the coupling coefficient variations on ZVS and ZDS conditions. The analytical estimations are validated through several LTSpice simulations and experimental results. The converter circuit, used for the proposed analysis, has been designed and simulated, and a laboratory prototype has been experimentally tested. The experimental prototype can transfer 83.5 W at optimal capacitive coupling with operating at 100 kHz featuring 92.5% of the efficiency, confirming that theoretical and simulation results are in good agreement with the experimental tests.

A simple digital control for mitigating voltage stress on single switch resonant inverter for induction cooking applications

ABSTRACT Single switch inverter is a prevalently used topology for domestic induction heating (IH) applications because of its crisp structure, high efficiency and low cost. The inherent issue with this single switch topology is that it has to withstand the whole power of the load and the huge resonating voltage due to the load current during the energy transfer by the capacitor. This process in due course will reduce the performance and also the life of the system. The cumulative stress on the switch due to dynamic variations in AC mains will cause thermal runaway on the switch. Also, this nonlinear operation at the load results in input current distortions. In this work, a simple voltage-limiting control is proposed to reduce the voltage stress of the switch and to maintain a high power factor. The control circuitry and its logic are verified for 500- W IH prototype. The test results reveal that the suggested scheme is simple and efficient in mitigating voltage stress as well.

Design of Single-Switch Inverters for Variable Resistance/Load Modulation Operation

Single-Switch inverters such as the conventional Class-E inverter are often highly load sensitive, and maintain zero-voltage switching over only a narrow range of load resistances. This paper introduces a design methodology that enables rapid synthesis of Class E and related single-switch inverters that maintain ZVS operation over a wide range of resistive loads. We treat the design of Class-E inverters for variable resistance operation and show how the proposed methodology relates to circuit transformations on traditional Class-E designs. We also illustrate the use of this transformation approach to realize Φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> inverters for variable-resistance operation. The proposed methodology is demonstrated and experimentally validated at 27.12 MHz in a Class E and Φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> inverter designs that operate efficiently over 12:1 load resistance range for an 8:1 and 10:1 variation in output power, respectively, and a 25-W peak output power.

ZVS single-switch inverter for induction heating – optimum operation

The optimum operation of a single-switch class E transistor inverter for induction heating has been discussed in the paper. The graphs of the most important inverter parameters as a function of the values of the resonant circuit components are shown. The results presented have been illustrated with some current and voltage waveforms obtained on the basis of mathematical analysis as well as using IsSpice simulation program. A concept of a control system has also been presented, which should ensure nearly optimum operation of the inverter. Streszczenie. W artykule omowiono prace optymalną jednolącznikowego tranzystorowego falownika klasy E do nagrzewania indukcyjnego. Przedstawiono wykresy najwazniejszych parametrow falownika w funkcji wartości elementow obwodu rezonansowego. Podano przykladowe przebiegi czasowe prądow i napiec w falowniku otrzymane zarowno na podstawie analizy matematycznej, jak i poprzez symulacje w programie IsSpice. Przedstawiono rowniez koncepcje ukladu sterowania falownika, ktory powinien zapewniac prace w warunkach bliskich optymalnym. (Jednolącznikowy falownik z przelączaniem ZVS do nagrzewania indukcyjnego praca optymalna)

Analysis and design of a self-oscillating class E ballast for compact fluorescent lamps

The Class E inverter is the basis for a low-cost high-frequency ballast, but the control system is more complex than the self-oscillating Class D inverter. The added complexity neutralizes any cost savings gained by the single switch inverter. This paper explores a novel self-oscillating Class E ballast from a design perspective. A qualitative analysis shows how this self-oscillating system operates, from startup, through ignition to the steady state. Optimum component values are found from a quantitative analysis of the inverter. This mathematical model is the basis for the design methodology. Analytical results are compared with the physical model.