Tomokazu Mishima

A High Frequency-Link Secondary-Side Phase-Shifted Full-Range Soft-Switching PWM DC–DC Converter With ZCS Active Rectifier for EV Battery Chargers

A new prototype of a secondary-side phase shift soft-switching PWM dc-dc converter suitable for electric vehicle battery charging systems is presented in this paper. Wide range soft-switching operations are achievable from full load to no load by effectively utilizing the parasitic inductances of the high frequency transformer in the proposed dc-dc converter. In addition, no circulating current occurs in both of the primary and secondary side full-bridge circuits; thereby, the related idling power can be minimized. As a result, high efficiency power conversion can be maintained owing to the full range soft-switching operation and wide range output power and voltage regulations. Its operating principle is presented on the basis of theoretical analysis and simulation results, and the design procedure of the circuit parameters of the proposed dc-dc converter is described. The essential performance and its effectiveness of the proposed dc-dc converter are originally demonstrated from a practical point of view in an experiment using a 1 kW-50 kHz laboratory prototype.

A Novel High-Frequency Transformer-Linked Soft-Switching Half-Bridge DC–DC Converter With Constant-Frequency Asymmetrical PWM Scheme

This paper presents a novel soft-switching half-bridge dc-dc converter with high-frequency link. The newly proposed soft-switching dc-dc converter consists of a single-ended half-bridge inverter controlled by an asymmetrical pulsewidth-modulation scheme and a center-tapped diode rectifier. In order to attain the wide range of soft commutation under constant switching frequency, the single active edge-resonant snubber cell composed of a lossless inductor and a switched capacitor is employed for the half-bridge inverter leg, providing and assisting zero-current-switching operations in the switching power devices. The practical effectiveness of the proposed soft-switching dc-dc converter is demonstrated by the experimental results from an 800 W - 55 kHz prototype. In addition, the feasibility of the dc-dc converter topology is proved from the viewpoints of the high efficiency and high power density.

Bidirectional DC-DC Converter with Full-bridge / Push-pull circuit for Automobile Electric Power Systems

In recent years, energy storage systems assisted by super capacitor have been widely researched and developed to progress power systems for the electronic vehicles. In this paper, a full-bridge/push-pull circuit-based bidirectional DC-DC converter and its control methods are proposed. From the results of detailed experimental demonstration, the proposed system is able to perform adequate charge and discharge operation between low-voltage high-current super capacitor side and high-voltage low-current side with drive train and main battery. Furthermore, conduction losses and voltage/current surge are drastically reduced by ZVS operation with loss-less snubber capacitor in high voltage side as well as the synchronous rectification in low-voltage high-current super capacitor side.

A New Current Phasor-Controlled ZVS Twin Half-Bridge High-Frequency Resonant Inverter for Induction Heating

A novel soft-switching high-frequency (HF) resonant (HF-R) inverter for induction heating (IH) applications is presented in this paper. By adopting the current phasor control of changing a phase shift (PS) angle between two half-bridge inverter units, the IH load resonant current can be regulated continuously under the condition of wide-range soft-switching operations. In addition to this, the dual-mode power regulation scheme-based PS angle control and asymmetrical pulsewidth modulation in one inverter unit is proposed for improving the efficiency in low output power settings. The essential performances on the output power regulation and soft-switching operations are demonstrated in an experiment using its 1-kW 60-kHz HF-R inverter prototype, and then, the topological validity is evaluated from a practical point of view.

Practical Evaluations of a ZVS-PWM DC–DC Converter With Secondary-Side Phase-Shifting Active Rectifier

This paper presents a feasibility investigation of a zero-voltage switching (ZVS) pulsewidth modulation (PWM) dc-dc converter with secondary-side phase-shifting power control scheme. The ZVS-PWM dc-dc converter treated here can achieve soft commutation in all the power devices under the wide range of output power variation. By the phase-shifting control that is based on the secondary-side rectifier linked with a high-frequency planar transformer, the effective reduction of idling power in the primary-side inverter as well as snubber-less rectifications in the secondary-side rectifier can be actually attained. The essential experimental data obtained from a 100-kHz/2.5-kW prototype are described herein to validate the soft-switching circuit and control scheme, and then the effectiveness of the dc-dc converter is discussed and evaluated from a practical point of view.

A Load-Power Adaptive Dual Pulse Modulated Current Phasor-Controlled ZVS High-Frequency Resonant Inverter for Induction Heating Applications

A new prototype of an efficiency-improved zero voltage soft-switching (ZVS) high-frequency resonant (HF-R) inverter for induction heating (IH) applications is presented in this paper. By adopting the dual pulse modulation mode (DPMM) that incorporates a submode power regulation scheme such as pulse density modulation, pulse frequency modulation, and asymmetrical pulse width modulation into main one of the resonant current phase angle difference ( θ) control, the IH load power can be widely regulated under the condition of ZVS, while significantly improving the efficiency in the low output power setting. The essential performances on the output power regulations and ZVS operations with the DPMM schemes are demonstrated in an experiment based on a 1 kW-60 kHz laboratory prototype of the ZVS HF-R inverter. The validity of each DPMM scheme is originally compared and evaluated from a practical point of view.

A Practical ZCS-PWM Boost DC-DC Converter With Clamping Diode-Assisted Active Edge-Resonant Cell and Its Extended Topologies

This paper presents the performance evaluations of a zero current soft-switching pulse width modulation (ZCS-PWM) boost dc-dc converter with a practical active edge-resonant cell (AERC). The AERC treated and discussed herein has auxiliary diodes for suppressing voltage surges and current ringings at the commutations of active switches in the dc-dc converters. The voltage surges together with the current ringings can be effectively eliminated in the AERC owing to the effect of the clamping diodes. Therefore, voltage ratings of the active switches can be considerably reduced as compared to the classical AERC without the clamping diodes, consequently the conversion efficiency can be improved in the ZCS-PWM boost dc-dc converter. The practical effectiveness of the clamping diode-assisted ZCS-PWM boost dc-dc converter is demonstrated in detail by means of experimental verifications based on a 1.6 kW-40 kHz laboratory prototype. In addition, an extended topological family of nonisolated ZCS-PWM dc-dc converters employing the practical AERC is originally described for demonstrating the high scalability of the AERC.

High-frequency resonant matrix converter using one-chip reverse blocking IGBT-Based bidirectional switches for induction heating

This paper deals with a novel type soft switching utility frequency AC-high frequency AC converter using asymmetrical PWM bidirectional active switches which can be defined as high frequency resonant matrix converter. This power frequency changer can directly convert utility frequency AC power to high frequency AC power ranging more than 20 kHz up to 100 kHz. Only one active edge resonant capacitor-assisted soft switching high frequency load resonant cyclo-converter is based on asymmetrical duty cycle PWM strategy. This high frequency cyclo-converter uses bidirectional IGBTs composed of anti-parallel one-chip reverse blocking IGBTs. This high frequency cyclo-converter has some remarkable features as electrolytic capacitorless DC busline link, unity power factor correction and sinewave line current shaping, simple configuration with minimum circuit components and low cost, high efficiency and downsizing. This series load resonant cyclo- converter incorporating bidirectional active power switches is developed and implemented for high efficiency consumer induction heated food cooking appliances. Its operating principle is described by using equivalent circuits. Its operating performances as soft switching operating ranges and high frequency effective power regulation characteristics are discussed on the basis of simulation and experimental results.

A Bridgeless BHB ZVS-PWM AC–AC Converter for High-Frequency Induction Heating Applications

Performances of a zero voltage soft-switching (ZVS) pulse-width-modulated (PWM) utility frequency ac (UFAC) to high-frequency ac (HFAC) resonant power converter for induction heating (IH) applications are presented in this paper. The series resonant ac-ac converter proposed herein can process the frequency conversion without any diode bridge rectifier (DBR), thereby reducing the relevant conduction power losses. Power factor correction (PFC) can be naturally achieved by the inductor-based boost half-bridge (BHB) circuit with the non-smoothed dc-link. The characteristics of the non-smoothed dc-link stage including PFC and voltage regulations are demonstrated in an experiment with a 3.0kW-30 kHz prototype. Finally, the feasibility of the proposed ac-ac converter is evaluated from a practical point of view.

Analysis, Design, and Performance Evaluations of an Edge-Resonant Switched Capacitor Cell-Assisted Soft-Switching PWM Boost DC–DC Converter and Its Interleaved Topology

This paper presents a soft-switching pulsewidth modulation (PWM) nonisolated boost dc-dc converter embedding an edge-resonant switched capacitor (ER-SWC) cell and its interleaved circuit topology. The conceptual boost dc-dc converter treated herein can achieve high-frequency zero-current soft-switching turn-on and zero-voltage soft-switching turn-off operations in the active switches and minimization of a reverse recovering current in the freewheeling diode under discontinuous conduction mode partially including critical conduction mode in the input current. Those advantageous properties enable a wide range of soft-switching operations together with a high-voltage step-up conversion ratio with a reduced current stress. Circuit design guideline based on the soft-switching range is introduced; then, a theoretical analysis is carried out for investigating the step-up voltage conversion ratio. For demonstrating the effectiveness of the ER-SWC soft-switching PWM boost dc-dc converter and its newly developed interleaved topology, laboratory prototypes are evaluated in experiments; then, their performances are discussed from a practical point of view.