Quasi-resonant Topology Research Articles

Sizing by SQP optimization of an electrical drive: Application to a switched capacitor connected to a permanent magnet synchronous generator

The paper deals with the design by optimization in pre-sizing step of a drive system that combines a switched capacitor system and a permanent magnet synchronous machine (PMSM). The sizing of the converter and the machine are considered strongly dependent due to the series quasi-resonant topology. The system modelling is based on a semi-analytical approach validated by finite element (FE) simulations. It involves an analytical modelling of the electrical machine and a numerical time solving of the electrical circuit sub-model because of the natural switching events of diodes. The optimization is carried out by SQP (Sequential Quadratic Programming). The model gradients are computed combining mathematical laws, symbolic derivation and automatic differentiation. Finally, trade-offs and gains on the machine power density, the magnet volume and the efficiency are investigated through a Pareto approach.

Bidirectional Isolated Single-Stage Single-Phase AC–AC Converter

The objective of this paper is to propose a bidirectional isolated single-stage single-phase ac-ac converter (BISS-converter) with quasi-resonant (QR) topology. The proposed converter is composed of multiple bidirectional flyback type dc-dc converters (BFDCs) and two bidirectional dc-ac unfolders. Because the unfolder only switches at the zero crossing of the ac line voltage, there is only one set of high-frequency pulse width modulation (PWM) signal, which is used to control the BFDCs to generate the desired rectified sinusoidal currents. Advantages of the proposed BISS-converter include high conversion efficiency, single-stage high-frequency power conversion, simple control circuit, flexible capacity, and bidirectional power flow capability. Moreover, the controller can maintain the zero voltage switching to reduce the switching loss without the need for valley detection. Also, with the interleaved operation between BFDCs, the current ripple of the output can be reduced greatly. The hardware experimental results are shown to verify the performance of the proposed BISS-converter.

Analysis of the Input Current Distortion and Guidelines for Designing High Power Factor Quasi-Resonant Flyback LED Drivers

Nowadays, LED lamps have become a widespread solution in different lighting systems due to their high brightness, efficiency, long lifespan, high reliability and environmental friendliness. The choice of a proper LED driver circuit plays an important role, especially in terms of power quality. In fact, the driver controls its own input current in addition to the LED output current, thus it must guarantee a high power factor. Among the various LED drivers available on the market, the quasi-resonant (QR) flyback topology shows interesting benefits. This paper aims at investigating and analyzing the different issues related to the input current distortion in a QR flyback LED driver. Several effects, such as the distortion caused by the ringing current, crossover distortion due to transformer leakage inductance and crossover distortion due to the input storage capacitor have been experimentally reported. These effects, not previously studied for a high power factor (Hi-PF) QR flyback, have been analyzed in depth. Finally, some practical design guidelines for a Hi-PF QR flyback driver for LED applications are provided.

Wireless power supply for rotating piezoelectric actuators in high performance aeronautic drilling systems

In this paper, a contactless power transfer system is presented. It is designed to supply piezoelectric actuators with a low frequency signal and a DC offset. A power electronic structure based on a full bridge PWM inverter, a resonant capacitor, an inductive rotating transformer which works at low frequencies and the piezoelectric actuator is presented and modeled. The behavior of the system is analyzed regarding the variation of the transformer’s coupling coefficient and the resonant capacitor value. Then, an optimization tool is presented where magnetic and power properties of the system are optimized in terms of electrical performances and volume. An embedded passive electronic system, that creates the mandatory DC offset for the actuator, is shown. Experimental results obtained with the prototype are exposed and compared to the simulations. Based on these results, a new version with a secondary quasi-resonant topology has been studied allowing both to reduce the size of the transformer and the global efficiency.

Multi-Output Power Converter, Operated from a Regulated Input Bus, for the Sireus Rate Sensor

This paper describes a DC to DC converter designed to meet the power supply requirements of the SiREUS Coarse Rate Sensor (CRS) which is a 3-axis MEMS Rate Sensor (MRS) that uses a resonating ring gyro and will be used in different ESA missions. The converter supplies +5V, −5V, 3.3V, 1.8V and 40V and it has been designed and prototyped by Clyde Space Ltd with the EQM and FM units being manufactured by Selex ES. The first model was designed for a 28V un-regulated bus and the second model presented here has been designed for a 50V regulated bus. PWM voltage regulation was not used because of the noise requirements and the regulated input bus allowed an unregulated power stage approach. There are also stringent volume and interface constraints, which also affected the design. For such reasons, a fixed dutycycle, quasi-resonant single-ended topology with output linear regulators has been implemented; having the advantages of providing low switching losses, low radiated and conducted noise and no over-voltage failure mode. This paper highlights the techniques used to satisfy stringent noise and protection requirements of the load.

Performance Analysis of High frequency Parallel Quasi Resonant Inverter Based Induction Heating System

This paper presents the performance analysis of high frequency parallel quasi-resonant converter for domestic induction heating application as well as industrial application. The power semiconductor switch like IGBT is incorporated in this high frequency converter. Parallel Quasi-resonant topology is selected to provide ZVS and ZCS operation during switching conditions to reduce switching losses. Here, IGBT provides better efficiency and faster switching technique. In the proposed topology, a diode is connected across the IGBT ensuring the ZVS operation during turn-ON that enhances the possibility of less turn-ON loss. On the other hand, the switching frequency nearly equal to the resonant frequency ensures the ZCS operation of the IGBT during turn-OFF, which also ensures a reduction of turn-OFF loss. As a result, the performance of the induction heating system gets improved. The proposed scheme is analyzed using PSIM software environment.

Optimisation of the reverse conducting IGBT for zero‐voltage switching applications such as induction cookers

The reverse conducting-IGBT (RC-IGBT) is a well suited device for soft switching applications, that is, zero voltage switching (ZVS). However, standard RC-IGBTs are optimised for hard switching, which shows different switching waveforms compared with soft switching. In this study, the optimisation of the RC-IGBT is described for soft switching applications using the example of an induction cooker. The investigated induction cooker is implemented by using the single-ended quasi-resonant topology. Simulations show that main losses of the induction cooker occur in the induction coil and the RC-IGBT (power switch). The performance of the coil can be improved mainly by minimising the coil resistance. The IGBT-optimisation is based on the reduction of tail current in the soft switching mode. The IGBT thickness is decreased and the local lifetime is used to achieve lower tail current. A reduction of the overall losses by 30% is achievable. As a result, the cooling system of the IGBT can be smaller and cheaper.

Design of Dimmable Quasi-Resonant Fly Back LED Driver Based on OZ9992

The paper designs a 30W dimmable constant current LED driver. It is designed by O2Micros OZ9992 control chip, and it use quasi-resonant flyback topology. It can achieve zero voltage to reduce switching losses. The LED driver has higher efficiency and can provide a stable current for LED lamps. It has good dimming performance, and is easy to operate. It is suitable for home, hotel and other occasions, and has broad application prospects.

Quasi-resonant soft-switching inverter for low and high power factor loads

A novel quasi-resonant three-phase inverter is proposed for 400 or 50 Hz low and high power factor loads. The proposed quasi-resonant DC link consists of a total of four switches, two resonant inductors and a capacitor. Two switches are connected in series with the resonant DC link (RDCL) and the other two are connected across the RDCL. The quasi-resonant link topology is versatile and the operation is such that the DC link voltage is clamped to the source voltage. The soft-switching operation of the quasi-resonant inverter is explained in terms of modes for both positive and negative link current. The quasi-resonant inverter is operated under modified space vector modulation incorporating soft switching. SABER simulation of the resonant link inverter and subsequent experimental verification show good agreement.

A unified approach to class E versus quasi-resonant switch topologies

A generalized methodology of achieving class E versus quasi-resonant (QR) switching is introduced, and the associated resonant switch topologies are analyzed, with the conclusion that class E operation can be achieved for a given switching edge if the respective current or voltage is continuously differentiable (C/sup 1/) through the switching instant. This concept is applied to show how the category of class E switches includes the QR switches, but contains a wider variety of configurations.

PWM technique utilisation in the quasiresonant convertor

The quasiresonant forward convertor topology has a high power conversion efficiency due to the favourable switching conditions for the transistors and output rectifier diodes. In addition, this topology can employ output transformer parasitics in the resonant tank which makes it attractive for high voltage switched mode power supply applications. Unfortunately, a very broad range of operating frequency is required to control the output power, and therefore the highly efficient pulse width modulation (PWM) control technique in this resonant topology looks very promising. The adverse effects of the associated nonzero current turn-off switching can be reduced by using nondissipative snubbers. The resulting, PWM-controlled quasi-resonant convertor topology combines the advantages of both resonant power conversion and pulse width modulation techniques. The paper reports the analysis and PWM control characteristics of this hybrid convertor topology. An optimum operating mode of the quasiresonant convertor is identified and expressions for the optimum convertor parameters are derived. A 2.5 kW, 4 kV, 50 kHz convertor prototype for microwave heating was built to verify the analytical results.

A general approach to synthesis and analysis of quasi-resonant converters

A method for systematic synthesis of quasi-resonant (QR) topologies by addition of resonant elements to a parent pulse-width modulation (PWM) converter network is proposed. It is found that there are six QR classes with two resonant elements, including two novel classes. More complex QR converters can be generated by a recursive application of the synthesis method. Topological definitions of all known and novel QR classes follow directly from the synthesis method and topological properties of PWM parents. The synthesis of QR converters is augmented by a study of possible switch realizations and operating modes. In particular, it is demonstrated that a controllable rectifier can be used to accomplish the constant-frequency control in all QR classes. Links between the QR converters and the underlying PWM networks are extended to general DC and small-signal AC models in which the model of the PWM parent is explicitly exposed. Results of steady-state analyses of selected QR classes and operating modes include boundaries of operating regions, DC characteristics, a comparison of switching transitions and switch stresses, and a discussion of relevant design trade-offs. >

DC-to-AC inversion using quasi-resonant techniques

It is demonstrated that two basic approaches can be taken to achieve DC-to-AC inversion. The first, the differential load excitation (DLE) scheme, uses two converters, driven out of phase, to drive a load differentially. Unfortunately, this scheme requires a large number of components when it is implemented using quasi-resonant techniques. A more component-effective approach uses switched source excitation (SSE) schemes. One SSE approach uses two converters, each handling one polarity of the signal. By appropriate switching, an amplified signal is reconstructed at the output. The second SSE approach entails only one converter but with a slightly more involved switching requirement. It allows a significant overall reduction in the number of components needed and reduced performance requirements on most of the switches, since most switch at the lower inversion-frequency rate. A number of quasi-resonant inverter topologies from two broad categories are presented. For applications that require inverters to supply reactive power, three schemes which can be applied to various inverters, thus affording them reactive load handling capability, are discussed. >

Comparison of the square-wave and quasi-resonant topologies

The waveforms of a square-wave DC-DC converter and a quasiresonant DC-DC converter are examined in detail and a comparison is made between the switching losses and conduction losses for each topology. Using data from commercially available semiconductor devices, conservative estimates are then given for the switching frequency at which the resonant approach becomes advantageous. The effect of an isolation transformer on this comparison is also addressed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>