Novel zero-current-switching (ZCS) PWM switch cell minimizing additional conduction loss

A new family of zero-current-switching (ZCS) pulsewidth-modulated (PWM) converters, which uses a new ZCS PWM switch cell, is presented. The main switch and auxiliary switch operate at zero-current-switching turn-on and turn-off, and the all passive semiconductor devices in the ZCS-PWM converter operate at zero-voltage-switching turn-on and turn-off. Besides operating at constant frequency and with reduced commutation losses, these new converters have no additional current stress in the main switch in comparison to the hard switching converter counterpart. The PWM switch model and state-space averaging approach is used to estimate and examine the steady-state and dynamic character of system. The new family of ZCS-PWM converters is suitable for high-power application using insulated gate bipolar transistors. The principle of operation, theoretical analysis and experimental results of the new ZCS-PWM boost converter, rated at 1 kW and operating at 30 kHz, are provided to verify the performance of this new family of converters.

This paper proposes a new single-phase high-power-factor rectifier, which features regulation by conventional pulsewidth modulation (PWM), soft commutation, and instantaneous average line current control. A new zero-current switching PWM (ZCS-PWM) auxiliary circuit is configured in the presented ZCS-PWM rectifier to perform ZCS in the active switches and zero-voltage switching (ZVS) in the passive switches. Furthermore, soft commutation of the main switch is achieved without additional current stress by the presented ZCS-PWM auxiliary circuit. A significant reduction in the conduction losses is achieved because of the following reasons: 1) the circulating current for the soft switching flows only through the auxiliary circuit; 2) a minimum number of switching devices are involved in the circulating current path; and 3) the proposed rectifier uses a single converter instead of the conventional configuration composed of a four-diode front-end rectifier followed by a boost converter. Seven transition states for describing the behavior of the ZCS-PWM rectifier in one switching period are described. The PWM-switch model is used to predict the system performance. A prototype rated at 1 kW, operating at 60 kHz, with an input alternating current voltage of 220 V/sub rms/ and an output voltage of 400 V/sub dc/, has been implemented in laboratory. An efficiency of 98.3% and a power factor over 0.99 have been measured. Analysis, design, and the control circuitry are also presented in this paper.

This paper introduces a novel family of pulse-width- modulated (PWM) converters, which uses a new zero-current- switching (ZCS) PWM switch cell, featuring ZCS of all the active switches and zero-voltage-switching (ZVS) of all the passive semiconductor devices at entire load range. Besides operating at constant frequency and with reduced commutation losses, these new converters have less current stress and voltage stress in comparison to the general ZCS-PWM converter counterpart. In the paper, the theoretical analysis and the operation principles of a novel ZCS-PWM boost converter taken as an example will be described before the new converters are proposed. The validity of the proposed ZCS technique has been verified by the experimental results, which are obtained from a lkW, 50 kHz, new ZCS-PWM boost converter at full load.

A novel interleaved boost dc/dc converter with zero‐current‐switching pulse‐width‐modulation (ZCS‐PWM) characteristic using a simple ZCS‐PWM auxiliary circuit is presented in this paper. The proposed converter combines the conventional PWM technique and ZCS technique to promote the circuit performance. The proposed converter uses dual boost converters which are operated at interleaved mode to increase the output power level. Thus, the proposed converter does not only decreases the current stress on main circuit devices but reduces the input ripple current and output capacitor size. Because the proposed converter establishes a common ZCS‐PWM auxiliary circuit on used dual boost converters, it can greatly reduce the size and cost. And, it can provide the ZCS characteristic on main switches and auxiliary switches with a wide range of load to improve the problem of switching losses and EMI. Thus, its topology is simple and compact. Besides operating at constant frequency and reducing commutation losses, the proposed converter has no additional current stress and conduction loss in the main switch compared with the conventional interleaved boost dc/dc converter. The principle of operation, theoretical analysis and experimental results of the proposed boost converter, rated 1 kW and operating at 40 kHz, are provided in this paper to verify the performance of this new family of converters.

A fully soft switched high step‐up/down bidirectional converter is presented in this paper. The high voltage conversion ratio is achieved by a pair of coupled inductors along with a switched capacitor while all active switches operate at zero voltage switching. To provide soft switching condition for the main switches and absorb the leakage inductance energy of coupled inductors, active clamp circuits are utilized for both operating modes. Furthermore, all active switches body diodes which are utilized as converter diodes turn off at zero current switching (ZCS) and thus, the reverse recovery problem is eradicated. Additionally, the voltage stress of the main switches is reduced in comparison with the basic bidirectional buck/boost converter and thus, their drain‐source resistance is relatively lower which leads to considerably lower conduction loss. All the mentioned advantages along with relatively low number of components contribute to the converter efficiency. Theoretical analysis of the proposed converter is presented in detail for both operating modes and the experimental results from the implementation of a 300 W prototype circuit confirm the validity of the converter performance. A comprehensive comparison table between the proposed converter and the recent counterpart bidirectional converters is presented to demonstrate the converter advantages.

This paper proposes a new high-gain soft-switching dc–dc topology based on a switched inductor boost converter (SIBC). A conventional SIBC as a high gain boost topology has the issues of high conduction loss in switching diodes and high switching loss in the main switches. Also, it has severe electromagnetic interference (EMI) issue due to high-frequency ringing formed by parasitic inductance and diode junction capacitors. The new topology is derived with the objective of achieving zero voltage switching (ZVS) turn on of the main switch. Instead of adding extra active clamp zero voltage transition (ZVT) path at the switching node, the proposed topology augments the auxiliary ZVT path to the switching diode path. This is achieved by replacing the switching diodes with synchronous switches. The new topology can achieve soft switching for all the switches and alleviate the EMI issue. All the diodes achieve zero current switching (ZCS) turn off without reverse recovery. Auxiliary switches have ZCS turn on and ZVS turn off , and the main switches have ZVS turn on . The soft-switching SIBC also reduces the conduction loss in the switching diodes. A numerical simulation in PLECS and a prototype hardware are built corresponding to a micro-inverter application with 100 kHz switching frequency. Peak power conversion efficiency of 94.76% is achieved in the hardware prototype with Si devices.

A number of soft-switching pulse-width-modulated (PWM) converter techniques have been proposed, aimed at combining the desirable features of both the conventional PWM and resonant converters while avoiding their respective limitations. In this paper, three classes of zero-voltage soft-switching PWM converters (namely the zero-voltage switched (ZVS) quasi-square-wave converters, ZVS-PWM converters, and zero-voltage-transition PWM converters) and two classes of zero-current soft-switching PWM converters (namely the zero-current-switched PWM converters and zero-current-transition PWM converters) are reviewed; their merits and limitations are assessed. Experimental results of several prototype of converters are presented to illustrate each class of converter.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Pulse width modulation (PWM) switching technique is commonly used in full bridge converters to overcome the bulky filter requirements and efficient voltage control, at the cost of higher switching losses. However, all PWM techniques not only cause circuit complexity but also need high frequency switches such as MOSFETs with high conduction drop causing lower efficiency. This paper presents a novel sine wave inverter circuit which uses a full bridge topology with a PWM DC link. The PWM DC link is generated by using a buck switch in series with the DC source which is switched with unipolar sine PWM signal continuously. The bridge inverter switches are supplied with line frequency gate signals which are synchronized with the original modulating sine wave signal. The proposed inverter uses five switches out of which only one switch is switched at high frequency, while other switches operate at low (line) frequency which not only make the overall efficiency high but also make the voltage control simple as only one switch is supplied with controllable PWM signal. The proposed topology with switching technique was simulated and a prototype model was developed in the laboratory to prove its feasibility.

This paper presents a novel DC-DC converter for high-step-up applications. The converter combines an active switched inductor (ASI) circuit and a snubber circuit to increase gain and provide soft switching for all semiconductor devices. With the use of a single-core coupled inductor, high voltage gain is achieved. The snubber circuit further contributes to the gain enhancement. The switches turn on under zero current switching (ZCS) conditions, while all diodes operate under ZCS. In addition, the snubber capacitor provides zero voltage switching (ZVS) when the switches turn off. The low voltage stress on the switches enables the use of switches with low on-resistance, which reduces conduction loss. Additionally, the advantage of current sharing leads to a greater reduction in switch conduction loss. The theoretical analysis of the proposed converter is explained in detail. Furthermore, a prototype with an input voltage of 40V and an output voltage of 400V is implemented to demonstrate the efficacy of the proposed topology.

This paper present the power factor improvement technique in the midpoint converter-based switched reluctance motor (SRM) drive using an AC-DC three level pulse width modulation (PWM) converter. A conventional SRM drive produces very high level of harmonics content and poor power factor at AC mains. The proposed converter with midpoint converter fed SRM drive improves the power factor at AC mains with low current harmonics. The SRM drive with converter is modelled and its performance is simulated in MATLAB/Simulink environment.

Synchronous pulse width modulation (PWM) switching regulator is suitable for high-power applications because of its high conversion efficiency as compared with a linear regulator. A synchronous PWM chip integrating the control, output adjustment, output monitoring and protection functions of a switching regulator is designed for the power supply of high-performance CPUs. This chip is fabricated with a 1.7 /spl mu/m BiCMOS process successfully and a synchronous switching power system is established. The test result shows this system has high efficiency, high precision, fast transient response and small start-up overshoot.

In this paper, a new ZVT-PWM DC-DC boost converter is proposed. In the proposed new converter, the main switch turns on under Zero Voltage Transition (ZVT) and turns off under Zero Voltage Switching (ZVS). Besides, the auxiliary switch turns on under Zero Current Switching (ZCS) and turns off under Zero Current Transition (ZCT). Also, the other semiconductor elements softly turn on and turn off under ZVS or ZCS. Another feature of proposed converter is that there is no additional current or voltage stress on the main switch and main diode. Also, there is no additional voltage stress on the auxiliary switch and the auxiliary diodes. The proposed new converter operates even under light load conditions and it has advantages as the simple structure, the low cost and easy control. Firstly, the theoretical analysis of the proposed converter is made. Then, the operating stages, the key waveforms and the simulation results of the new converter operated for 500 W and 40 kHz is given in detail.

TDA 16888 is designed for off-line switched mode power supplies (SMPS) with optional universal input and power factor correction, for example, for PCs, monitors, CTVs and industrial applications. Combi-IC TDA 16888 includes the pulse width modulated (PWM) control for a SMPS and the control for the preconverter to improve the power factor and to reduce the harmonics of the AC input current. Both sections are internally synchronized on the same operating frequency. The preferred topology of the PFC-preconverter is boost, but flyback is also possible. The PWM section can be designed as a forward or as a flyback converter. Maximum duty cycle of the PFC is about 95%, in order to achieve minimal line current gaps. Maximum duty cycle of the PWM is limited to 50% to prevent transformer saturation. In normal operation the PFC section operates with dual loop control. A first control loop controls the shape of the line current by average current control enabling either continuous or discontinuous operation mode. The second loop controls the DC bus voltage. There is a third control loop available that enables the PFC section as an auxiliary power supply even during disabling the PWM section. In this paper the PFC preconverter, PWM converter, PFC and PWM gate drive, and oscillator and synchronisation are described.

A new family of zero-voltage transition (ZVT) pulse width modulation (PWM) converters is introduced. In this converter family there is no additional voltage stress on the main switch in comparison to the hard switching counterpart. Also, the voltage and current rating of the auxiliary switch is low. The proposed zero-voltage transition PWM buck converter is analysed and design considerations are discussed. A prototype converter is implemented and the experimental results are presented.

In this paper, a new pulse width modulation (PWM) converter is proposed. This structure converts the analog input signal to a PWM waveform using only inverters/charge-pumps in combination with passive elements. Thus, the proposed PWM converter does not need any operational amplifier. The added feedback path current can be used to adjust the required duty-cycle of the PWM conversion based on the dynamic range of the input signal. The behavior of the proposed PWM converter is formulated and simulated in a 0.13μm CMOS technology. From the simulation results, the proposed PWM converter achieves 74dB linearity and draws only 1.0mA at 500MHz from 1.0V supply in a 0.13μm process.