H. Yonemori

Three-phase ZVS-PWM inverter system with transformer-assisted quasi-resonant DC link and its feasible comparative evaluations

The purpose of this paper is to confirm the reduction level of the switching losses and EMI noise in the novel zero voltage switching (ZVS) PWM three-phase inverter system which composed the transformer-assisted quasi-resonant DC link (TQRDCL) topology by means of comparative experimental study on TQRDCL inverter and conventional hard-switching ones. The operating principle and its characteristics of TQRDCL inverter system are illustrated and discussed. The air-conditioning system on the market is selected as the fundamental system of the experimental apparatus, and it is extend to the TQRDCL experimental system for this comparative study. The loss analysis is performed under various load ranges and system operating frequency. The EMI noise reduction level of the TQRDCL system is also illustrated from comparative experimental results.

Zero-voltage soft-switched PDM three phase AC-DC active power converter operating at unity power factor and sinewave line current

This paper is concerned with a newly improved version of the pulse density modulation (PDM) three-phase AC-DC converter including an active clamped resonant DC link (ACRDCL) and its digital signal processor (DSP) control strategy to achieve a unity power factor correction and sinewave line current shaping. The operating principle of the zero-voltage soft-switched three-phase AC-DC converter using ACRDCL under the control scheme of an instantaneous space voltage vector-based clamping-voltage distributed PDM (modified-PDM) scheme to improve its control response and operating performances is illustrated. Performance evaluations are discussed using simulation and experimental results, and a comparison with the conventional PDM converter is given. The experimental results of this active converter are shown from a practical point of view. Finally, the utility-interfaced ACRDCL double-converter system operating under the DSP controlled modified-PDM strategy is illustrated and evaluated by using simulation results under inductive load conditions.<<ETX>>

A novel space-voltage vector modulated sinewave three-phase inverter with high-frequency transformer-coupled resonant DC link

A novel type of quasi-resonant DC link (QRDCL) three-phase voltage-sourced inverter circuit topology operating under a commutation principle of the auxiliary high-frequency (HF) transformer-assisted zero voltage switching (ZVS)-PWM is presented. The basic operating principle of this power conversion circuit using auxiliary transformer-assisted QRDCL (TQRDCL) more suitable for CVCF/UPS, power active filter, switched-mode PWM converter, and new energy-interfaced power supplies for utility-interactive interconnection, is presented in this paper. Its operating characteristics are discussed and evaluated in terms of using the computer-aided simulation results. The experimental inverter circuit is tested and examined for CVCF/UPS systems on the basis of the hard switched PWM inverter. This tested equipment is discussed for linear and nonlinear electrical loads under the conditions of large load variations and voltage fluctuations from a practical point of view.<<ETX>>

Next generation space voltage vector controlled three-phase ZVS-PWM active AC-DC converter with auxiliary transformer-assisted resonant DC link

In this paper, a novel prototype of a zero voltage transition soft-switching PWM controlled three-phase AC/DC active power converter is presented, which incorporates a transformer-assisted resonant tank DC link (TQRDCL) topology. The instantaneous space vector modulated sinewave current synthesizing and power factor correction of this active rectifier with an instantaneous output DC power feedback loop are implemented by digital signal processor-based software and its related hardware.<<ETX>>

New space-vector controlled soft-switching three-phase PDM AC/DC converter with unity power factor and sinusoidal line current shaping functions

The authors describe a state-of-the-art pulse density modulation (PDM) AC/DC power converter with an active clamped resonant DC link (ACRDCL) and a DSP-based system control strategy which relates unity power factor correction and sinewave line current shaping. The operating principle of the soft-switched AC/DC power converter and the clamping-voltage distributed PDM (modified-PDM) strategy and its performances are illustrated and discussed using simulation results. Experimental results are evaluated.<<ETX>>

Next generation space voltage vector ZVT-PWM AC-DC active power converter with auxiliary transformer-assisted resonant DC link

In this paper, a novel prototype of zero voltage soft switching PWM three-phase AC/DC active power converter with a new transformer-assisted resonant tank DC link is presented for power factor correction, sinewave line current shaping and output DC voltage regulation. The instantaneous space voltage modulated sinewave current synthesizing scheme of this active rectifier with an instantaneous output DC power feedback loop is implemented by digital signal processor-based software and its related hardware. The simulation results of this soft-switched active rectifier are illustrated and discussed as compared with the other resonant DC link rectifiers and the hard-switched active rectifier.<<ETX>>

Three-phase CVCF sinewave ZVS-PDM cycloinverter using single-phase high-frequency inverter with synchronized ZVS-PWM resonant DC link

This paper presents a newly-proposed high-performance 3fCVCF power conversion conditioner incorporating a new quasi-resonant DC link (QRDCL) ZVS-PWM single-phase inverter and high-frequency transformer coupled cycloconverter cascade topology. The operating characteristics of a proposed QRDCL are described and evaluated on the basis of the computer-aided simulation analysis. In order to achieve significant improvements in high performance and quick control response, the specially-designed voltage pulse distributed vector control modulation (modified PDM) scheme is actually introduced through employing DSP-based control implementation. This instantaneous voltage vector controlled three-phase CCVF power conditioning system suitable for a low EMI, high-power density UPS is realized for linear and nonlinear electrical loads and its effectiveness under the operating conditions of large load variations from an experimental point of view. Furthermore, the synchronized ZVS-PWM resonant DC link high-frequency inverter using power MOSFET modules is precisely simulated by introducing the dynamic and steady-state modelling of power MOSFETs and its excellent operation is verified as compared with this QRDCL inverter circuit using ideal power switches.<<ETX>>

New bidirectional sinewave-modulated series resonant power conditioning system with high-frequency AC link

The authors describe a novel conceptual multistage topology of a sinewave-modulated DC-LFAC (DC-low-frequency AC) power conversion conditioning and processing system, which incorporate a phase-shifting PWM (pulsewidth modulation) series-resonant cycloinverter (inverter-coupled cycloconverter cascade circuit) with a high-frequency AC (HFAC) transformer link. Its advanced hardware of system control implementation uses instantaneous sinewave-modulated voltage regulation and compensation strategies, depending upon load disturbance and input DC voltage fluctuation, as well as an instantaneous power regenerating regulation scheme. A newly proposed breadboard using MOS-gate power transistor modules is demonstrated and experimentally tested for high-power-density AC mini-uninterruptible power supply. This series resonant cycloinconverter with HFAC link, which includes the control function of a bidirectional power flow, is evaluated as an AC power supply system for telecommunication and spacestation/aerospace energy situations in the next generation.<<ETX>>

Modern high-frequency inverter linked cycloconverter type sinewave power processing system using multi-resonant soft-switching PWM strategy

The authors describe a newly improved sinewave CVCF power conversion conditioning and processing system (PCS) with an HF link, which incorporates a zero voltage switching (ZVS) mode phase-shifted modulation (PSM) HF inverter with the voltage clamped quasiresonant pole (QR-P) subcircuits. The subcircuits include lossless capacitive snubbers and an HF transformer-linked cycloconverter operating under the ZVS principle based on HF-voltage source and forced-gate commutation schemes. The PCS operation principle is described using the voltage and current waveforms. The ZVS PSM HF inverter stage with the voltage-clamped QR-P subcircuits is analyzed under the conditions of a load-dependent current source model together with its simulation results. The design approach is described from a theoretical point of view. The simulation results of the proposed inverter-cycloconverter cascade PCS with voltage clamped soft switching PWM strategy and instantaneous voltage feedback loop are illustrated and discussed, including the experimental results.<<ETX>>

Three Phase Resonant DC Link PDM Active Converter with Unity Power Factor and Sinewave Current Shaping Functions

This paper presents the state-of-the-art Discrete Pulse Modulated(DPM) three-phase AC/DC power converter with an Active-Voltage Clamped Resonant DC Link (ACRDCL). Its DSP-based digital control strategy to realize a unity power factor correction and sinewave line current shaping is proposed. The operating characteristics are illustrated using simulational results and experimental data. In addition, the biderectional double power conversion circuit with a single stage of ACRDCL is demonstrated as an extended concept of the switched mode DPM rectifier treated here.