An auxiliary resonant soft switching matrix converter

In this paper, an improved Zero-Voltage-Transition (ZVT) two-cell interleaved boost Power Factor Correction (PFC) converter is proposed and investigated. A new auxiliary circuit is designed and added to two-cell interleaved boost converter to reduce the switching losses. Only one auxiliary switch is used in the active soft switching auxiliary circuit. The main advantage of this auxiliary circuit is that it not only provides ZVT in the boost switches but also provides soft switching in the auxiliary switch and passive diodes. Therefore, the switching losses of the converter can be reduced. Compared to the previous published soft switching interleaved boost converters, only one auxiliary switch is needed in the auxiliary unit, so the auxiliary unit and control circuit are simple. A 1kW, 50 kHz two-cell interleaved boost PFC converter with an improved ZVT auxiliary circuit has been simulated using average current control method and the results are presented. Simulation results show that the main switches, the auxiliary switch and passive diodes are operating under soft switching mode.

A soft switching boost converter that uses an auxiliary switch and resonant circuit is proposed in this paper. The main switch performs soft switching under zero voltage condition by using a resonant capacitor and an inductor, auxiliary switch and diode. The conventional boost converter generates switching losses at turn on and off and this reduces the whole system efficiency. But the soft switching boost converter reduces the switching losses more than the conventional boost converter. The efficiency is increased to 96% in this soft switching converter. This converter is suitable for applications such as high-efficiency converters, photovoltaic dc/dc converters, a power-factor-correction circuit, and battery chargers.

In this paper a novel soft switching isolated buck rectifier is proposed. Various switching state sequences of a three-phase three-switch buck-type unity power factor rectifier are reviewed and the value of switching power loss in each state transition is investigated. The switching power loss of the converter is decreased by using zero current switching (ZCS) method. The operation modes of the converter are explained and analyzed. By using an auxiliary circuit with a simple method of energy recovery, the current is diverted away from the main power switches before they are turned off; so, switching losses in the converter are reduced. In this topology, the power transformer has only the primary and the secondary windings and the transformer is demagnetized in each switching period without the demagnetizing winding. The auxiliary circuit consists of an auxiliary switch and a resonant inductance-capacitance circuit connected to the auxiliary switch. The proper operation of the converter is confirmed by the results obtained from the digital simulations.

In this article, a family of nonisolated zero voltage switching (ZVS) bidirectional dc–dc converters (BDCs) with simple auxiliary circuit and continuous current at low voltage side source ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$V_L$</tex-math></inline-formula> ) is proposed. The auxiliary circuit is only composed of a single switch, a capacitor, and a small inductor which is applied to all proposed nonisolated BDCs to provide soft switching condition for all semiconductor elements. Thus, in terms of components count, the presented converters are superior to other counterpart BDCs. In addition, the continuous current at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$V_L$</tex-math></inline-formula> is maintained, while the main and auxiliary switches in both operating modes are turned <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> and <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> at ZVS. Moreover, all diodes turn <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> at zero current switching which mitigate the reverse recovery problem. Hence, a suitable overall efficiency is achieved in all proposed BDCs. The proposed bidirectional buck/boost converter is analyzed for both step-up and step-down operating modes in details and a 100 W converter prototype is implemented to verify the main converter features and the theoretical analysis.

The widespread use of renewable energy resources brings forth a requirement for high-power, high-efficiency, high-control-bandwidth grid-tied converters. This paper proposes a three-level active neutral-point-clamped zero-current-transition (3L-ANPC ZCT) converter for the sustainable energy power conversion systems. The proposed multilevel soft-switching topology can effectively increase efficiency and switching frequency of the systems by almost eliminating turn-OFF losses and greatly reducing turn-ON losses of semiconductor devices. The soft commutations of the main devices are achieved with simple auxiliary circuit of two auxiliary switches and one LC resonant tank for each phase leg as in the case of a two-level ZCT converter. The voltage rating of the auxiliary switches is the same as main switches, and is clamped to half of dc voltage, while the current rating is much smaller. Furthermore, the auxiliary switches switch under zero-current condition and have no switching losses. Compared with existing three-level diode neutral-point-clamped zero-current-transition (3L-DNPC ZCT) converter, the number of components in auxiliary circuit is halved, so the volume and cost are reduced. In addition, the deterioration of the soft commutation due to the parasitic inductances in the 3L-DNPC ZCT inverter does not exist in the proposed topology. The operation principle and comparison with the 3L-DNPC ZCT are analyzed in detail in this paper. Eighty kilowatt half-bridge prototypes of the 3L-ANPC ZCT converter and the 3L-DNPC ZCT converter are built and their circuit operation and analysis are experimentally verified.

In this study, a new zero-voltage transition (ZVT)–zero-current transition (ZCT) quasi-resonant buck converter, which ensures zero crossings at any time required for soft switching (SS) and provides ZVT turn-on and ZCT turn-off together for the main switch of active snubber cell in buck converter is presented. The proposed circuit combines the most of the advantageous features of the circuits presented previously and overcomes most of drawbacks of these circuits by using only one auxiliary switch with fewer other components. Consequently, new ZVT–ZCT quasi-resonant buck converter, which is verified by a prototype of a 0.4-kW and 100-kHz circuit, is analysed in detail. All semiconductor devices operate under SS, the main switch is subjected to no additional voltage and current stresses, and the stress on the auxiliary switch is very low in the proposed new converter.

This paper proposes an interleaved zero voltage transition (ZVT) PWM buck converter. The proposed converter consists of two identical buck converter modules and an auxiliary circuit. The auxiliary circuit provides zero voltage switching condition for the main switches. Also, zero current switching condition for the auxiliary switch and diodes is achieved. The interleaved buck converter with the proposed auxiliary switch is analyzed. The simulation results of a 300W ZVT interleaved buck converter operating at 100 KHz are presented to justify the validity of theoretical analysis.

In this paper, a novel interleaved high step-up (HSU) converter is presented. The proposed converter features a large voltage gain and common input-output grounding. In this interleaved HSU converter, by using only one zero voltage transition (ZVT) auxiliary circuit with one auxiliary switch and low number of elements, soft switching (SS) performance for all the semiconductors over a wide range of load variations is achieved. This leads to advantages of high efficiency and low complexity, expense, and size. The characteristics of the proposed converter are compared to similar state of the art converters, and to confirm its effectiveness, the simulation results of the proposed converter are presented.

In this paper, a new soft switching flyback inverter for AC module application is proposed. Conventional flyback inverter suffers from low efficiency and high switch stress. In this converter, RCD snubber limits voltage spikes across the primary switch and dissipates the energy of leakage inductance of transformer. This paper introduces a new soft switching flyback inverter. The auxiliary circuit of the proposed inverter does not have any auxiliary switch and thus, the control circuit is simple. The auxiliary circuit provides soft switching condition for primary switch. In this paper, operating principles, theoretical analysis and design procedure are presented. Also, simulation results are presented to verify the validity of theoretical analysis.

This paper presents the application of “ripple correlation control (RCC)” maximum power point tracking (MPPT) algorithm for photovoltaic (PV) system employing dc-dc Cuk converter to maximize the output power of PV module. Soft switching commutation of the main and auxiliary switches at zerovoltage using active clamp technique allows the operation of the Cuk converter at very high switching frequencies with reduced size of reactive elements and electromagnetic interference. The combination of auxiliary switch, clamp capacitor and resonant inductor is used to exploit the advantage of high efficiency with zero switching losses. RCC technique uses the high frequency signal ripple, which makes it to converge asymptotically to the maximum power point independent of module configuration and parameters. The operating modes of converter for different switching time intervals are analyzed and design considerations are presented. The simulated performance of the converter with RCC MPPT over conventional MPPT algorithms is presented. The MPPT methods are compared on the basis of the time taken to track the maximum power point (MPP), steady state oscillations about MPP and dependence on array parameters. To evaluate the viability of ZVS Cuk converter with RCC MPPT, the entire system is simulated using MATLAB/SIMULINK platform for an 87 Wp solar PV system.

An improved soft switching dual-switch forward converter topology is proposed in this paper. Compared with conventional dual-switch forward converter, the proposed converter employs an auxiliary switch and a clamp capacitor to instead of two reset diodes. Therefore, its duty cycle can exceed 0.5 to achieve wide range input voltage, also soft switching can be achieved for all switches. Especially, voltage stress across main switches can be clamped at 1/2Vin, voltage stress across auxiliary switch can be clamped at Vin. In addition, due to clamp capacitor series with the transformer, duty ratio can be extended with equation Vo = {Vin(1-D)D}/N. Thus, as a kind of better cost-effective approach, it is very attractive for high input, wide range and high efficiency application.

Isolated converters find wide application in SMPS, telecommunication, rectifiers etc. Among these topologies flyback converter is best opted for SMPS applications due to its simplicity in design, operation and less component count. High frequency dc-dc converters are subjected to high switching losses hence an auxiliary switch is designed to perform soft switching in main switch. The devices used in the converter are operated either in ZVS or ZCS to reduce the switching loss of the converter. This improves the converter performance. The converter designed is simulated, realized and presented in detailed for a laboratory model of 1.08W, 3.3V, 50 kHz.

A soft-switching active snubber is proposed to reduce the turn-off losses of the insulated gate bipolar transistor (IGBT) in a buck power converter. The soft-switching snubber provides zero-voltage switching for the IGBT, thereby reducing its high turn-off losses due to the current tailing. The proposed snubber uses an auxiliary switch to discharge the snubber capacitor. This auxiliary switch also operates at zero-voltage and zero-current switching. The size of the auxiliary switch compared to the main switch makes this snubber a good alternative to the conventional snubber or even to passive low-loss snubbers. The use of the soft-switching active snubber permits the IGBT to operate at high frequencies with an improved RBSOA. In the experimental results reported for a 1 kW, 40 kHz prototype, combined switching/snubbing losses are reduced by 36% through the use of the active snubber compared to a conventional RCD snubber. The use of an active snubber allows recovery of part of the energy stored in the snubber capacitor during turn-off. The generic snubber cell for the buck power converter is generalized to support the common nonisolated DC/DC power converters (buck, boost, buck-boost, Cuk, sepic, zeta) as well as isolated DC/DC power converters (forward, flyback, Cuk, and sepic).

In this paper, the auxiliary switch control using lookup table is proposed to enhance the efficiency of a bi-directional DC/DC converter for EVs. The bi-directional DC/DC converter performs soft switching. It is difficult to obtain continuous current data at the resonant operation. The proposed auxiliary switch control has a look-up table reference of the auxiliary switch turn-on time. The control method properly controls the auxiliary switch turn-on time according to the required load current and is sufficiently safe and efficient in a regenerative mode. The validity of the proposed approach has been demonstrated by the experimental results on a bi-directional DC/DC converter, inverter, IPMSM.

In this paper, a new zero-voltage zero-current transition (ZVZCT) boost converter using coupled inductors is proposed. The feature of this topology is: the main switch can be switched on with ZVZCT, and off with zero-voltage switching, without any voltage and current stress. The auxiliary switch is turned on with zero-current switching. Other semiconductor devices can also achieve soft switching (SS). Due to the existence of the coupling effect, the current impact of the auxiliary switch is completely suppressed when it is turned off . Lower input current and output voltage in the interval of the switch- off for the auxiliary switch are just equivalent to running at a low power level, which is an additional advantage of the coupled inductor ZVZCT solution. Another advantage of the topology is that the SS condition of the main switch for each specific load can be effectively optimized just by setting the ratio of coupling inductance corresponding to the circuit design and application load. Thus, the topology design can be improved to adapt to different load types. A 100 kHz experimental prototype has been verified, different load for 1 and 0.4 kW optimization comparison has been presented, and the case without optimization is also observed.