Impact of Gamma Radiation on Dynamic RDSON Characteristics in AlGaN/GaN Power HEMTs

GaN high-electron-mobility transistors (HEMTs) are promising next-generation devices in the power electronics field which can coexist with silicon semiconductors, mainly in some radiation-intensive environments, such as power space converters, where high frequencies and voltages are also needed. Its wide band gap (WBG), large breakdown electric field, and thermal stability improve actual silicon performances. However, at the moment, GaN HEMT technology suffers from some reliability issues, one of the more relevant of which is the dynamic on-state resistance (R) regarding power switching converter applications. In this study, we focused on the drain-to-source on-resistance (R) characteristic…

Power system consumption model using SPICE

Space missions have very stringent mass, volume and also power budgets. This requires very precise knowledge of the power consumption of the whole satellite, not only peak power but also static and long term dynamic power. This calculation becomes very complex if all the operational modes (long term dynamic changes) are taken into account, including the different environmental situations. The power budget of any Power Converter Module (PCM), which includes not only the DC/DC converter but also the distribution unit, depends on the power it delivers and on external factors like temperature and input voltage. We propose to use a linear SPICE model using electronic models of discrete component…

Small-Signal Modeling of a Controlled Transformer Parallel Regulator as a Multiple Output Converter High Efficient Post-Regulator

This paper presents a post-regulator based on the use of a controlled transformer, which adds or subtracts an additional voltage to the output filter of a converter in order to regulate its output voltage. So, their actuation is complementary to that of more known post-regulators, such as the magnetic amplifier (magamp) and synchronous switch post-regulator (SSPR), because the regulation is achieved by controlling the voltage across the filter inductor instead of its charge time. Besides, the post-regulator processes the power in parallel to the one flowing from input to output and only handles a percentage of it. The post-regulation by controlled transformer is suitable of being employed i…

SiC Power Switches Evaluation for Space Applications Requirements

We have evaluated several SiC power switches available on the market, by defining and performing a global test campaign oriented to Space applications requirements, in order to define their main benefits but also the limits of current SiC technology. This allowed to identify a number of target applications where SiC could be used as a technology push for a new generation of space electronics units. Silicon devices qualified for space systems above 600V for the switches and 1200V for the rectifiers are not available due to performances limitations of Si. Among the typical static and dynamic characterization, we have performed temperature and power stress and HTRB tests. More remarkably, we h…

On the design of a multiple-output DC/DC converter for the PHI experiment on-board of solar orbiter

Power converters for experiments that have to fly on board space missions (satellite, launchers, etc.) have very stringent requirements due to its use in a very harsh environment. The selection of a suitable topology is therefore not only based on standard requirements but additional more strict ones have also to be fulfilled. This work shows the design procedure followed to build the Power Converter Module (PCM) for the Polarimetric and Helioseismic Imager (SO/PHI), experiment on board the Solar Orbiter Satellite. The selected topology has been a Push-Pull, for a power level of approximately 35 W and with seven output voltages. Galvanic isolation is needed from primary to secondary, but no…

Novel test bed for induction heating power supplies

Power supplies used in induction heating industrial applications must be entirely tested after its manufacturing in order to assure its security and reliability by means of a full power running test of several hours of duration. Nowadays this test is done with a dissipative load which implies a large waste of energy. This paper proposes a new high efficiency test system for induction heating generators. It incorporates a regenerative electronic load which allows an extraordinary improvement of the efficiency of this test with an important economical and ecological benefit.

Isolated two-stage passive PFC rectifier for the Radioisotope Stirling Generator

This paper describes an isolated, passive power factor correction rectifier devised for low-voltage, large-inductance, single-phase alternator, like the one used in the Radioisotope Stirling Generator. The power converter splits into two independent stages, the front-end rectifier corrects the power factor by adding a series capacitor in the AC line. Further, the rectifier, thanks to the alternator inductance, behaves as a constant-current source that powers a current-fed, zero voltage and zero current switching push-pull stage. This approach takes advantage of all parasitic elements to increase power density while keeping simple and reliable. Full description and analysis is given as well …

Circuit proposals for high-voltage latching current limiters

This work discusses some ideas to adapt existing low voltage Latching Current Limiter (LCL) circuits to high voltage operation to provide a basis for future designs. Component selection, driver and ancillary power supply are key issues discussed which eventually provides a high-voltage LCL proposal. Experimental validation of two different prototypes (380Vdc and 1kVdc) is included as well as some digital techniques to enhance LCL capabilities.

Failure analysis of normally-off GaN HEMTs under avalanche conditions

Gallium nitride (GaN) high electron-mobility transistors (HEMTs) are promising devices in the power electronics field owing to their wide bandgap (WBG). However, all the potential advantages provided by their WBG require reliability improvement. In industrial applications, robustness is one of the main factors considered by circuit designers. This study focuses on the observation of the degradation behavior of the main waveforms of unclamped inductive-switching (UIS) test circuits of two different commercial GaN HEMT structures. The relevance of this study lies in the potential applications of these devices to high-voltage applications and automotive systems where they are subjected to many…

Efficiency comparison between SiC- and Si-based active neutral-point clamped converters

This paper presents an efficiency comparison between silicon-carbide technology and silicon technology. In order to achieve this, the efficiency of an active neutral-point clamped converter built up with silicon carbide power-devices is compared with the efficiency of an active neutral-point clamped converter built up with silicon power-devices, under a particular operating mode and a particular selection of devices. Firstly, overall losses of both converters are estimated. Then, experimental tests are carried out to measure their overall losses and efficiency. Finally, experimental results are compared with the estimations to support the analysis. The efficiency of the SiC converter is hig…

Design of a power conditioning unit for a Stirling generator in space applications

The Free-Piston Stirling Generator (FPSG) is a thermal to electrical energy conversion system, based upon the thermal engine of the same name. Intensive research concerning the feasibility of the engine for its application in deep space and planetary missions has been conducted, primarily due to the potential increase in efficiency (−30%) over the currently used Radio-isotope Generators (RTGs). On the other hand, less attention has been paid to the power conditioning requirements and alternatives. The present work has investigated on the dynamics governing the FPSGs in order to assess the design requirements for the subsequent power-conditioning unit (PCU). Thereafter, two alternatives of A…

The Sequential Switching Shunt Maximum Power Regulator and its Application in the Electric Propulsion System of a Spacecraft

This paper describes a baseline solution of a Power Conditioning and Distribution Unit (PCDU) for Electrical Propulsion (EP) systems. The solution adopted uses two high efficiency, low-mass power regulators; a solar array regulator (SAR) based on the classical Sequential Switching Shunt Regulator with Maximum Power Point Tracking (MPPT) capability followed by a step-up converter to achieve the desired regulated bus voltage. This paper focuses on the first part of the PCDU, the Sequential Switching Shunt Maximum Power Regulator (S3MPR). This electrical architecture has been adapted and recently proposed for the Electric Propulsion power system of the European and Japanese Mercury Mission (Be…

Failure Rate Measurement on Silicon Diodes Reverse Polarized at High Temperature

This paper calculates the failure rate on reversed polarized silicon diodes with the aim to justify, experimentally, the rules of the European Space Agency (ESA) which are referred to the component life’s extension, the reliability increase and the end of life performance enhancement, by using oversized devices (derating rules). In order to verify the derating rules, 80 silicon diodes are used, which are reverse polarized in a high temperature environment. The diodes are divided in 4 groups of 20 diodes, applying a different voltage to each group, in order to relate the failure rate to the applied derating rule. The experiment described in this paper is developed using a temperature acceler…

Optimized Topology for High Efficiency Battery Discharge Regulator

In the following years power levels of 20 kW to 50 kW will be demanded by the telecommunication satellites. It is not possible to keep 0.5 kW modules with up to 100 modules in parallel and, therefore, higher power modules must be used. A higher bus voltage seems also necessary and any voltage below 150 V and above 100 V could meet the needs. In addition, new optimized topologies that process only a part of the total power delivery can be employed to improve the efficiency. In this article, design guidelines and experimental results of a high efficiency battery discharge regulator (BDR) module based on parallel power processing are given.

Evaluation of Gallium Nitride Transistors in Electronic Power Conditioners for TWTAs

The aim of this paper is to evaluate the benefits of replacing Si Mosfets transistors with enhancement mode GaN transistors in a Half-Bridge Zero Voltage and Zero Current Switching Power Switching Converter (ZVZCPS). This converter is usually used as power supply of the travelling-wave tube amplifiers (TWTAs) in aerospace applications. In this paper, firstly the converter is theoretically analyzed, obtaining its operation, losses and efficiency equations, these equations are used to obtain optimizations maps based on the main system parameters. In this way, the ideal design parameters can be visually obtained. These optimization maps are the key to quantify the potential benefits of GaN tra…

Output Impedance Improvement Using Coupled Inductors

When using a single DC/DC converter with multiple outputs and having a buck topology, which has one filter inductor per output, the designer can choose to couple these outputs together. This paper demonstrates additional benefits of coupling output inductors together. Apart from saving mass and volume, and due to an improved small signal behaviour it also reduces the output impedance of the regulated output. The paper will analyse a seven output push-pull converter used as a space power converter module and verify the theoretical results with experimental measurements.

New Power Conditioning System for Battery-free Satellite Buses with Maximum Power Point Tracking

The purpose of this paper is describe a new conception of Power Conditioning Unit (PCU) developed to fulfill the requirements of BepiColombo Electronic Propulsion module. This load bus has very tough specification especially regarding transient response during total load switch-off ("beam out") which has to be less than 2% of the bus voltage. The conception we propose, is the new Sequential Switching Shunt Maximum Power Regulator (S3MPR) consisting in a S3R, to keep the SA voltage at its Maximum Power Point (MPP) followed by a Boost regulator to produce a constant 100V to supply the Electronic Propulsion (EP). This concept may also be of interest for other future missions involving high pow…

Soft switched interleaved boost converters used as high-power battery discharge regulator for space power systems

In the following years the telecommunication satellites will have a much greater power demand than nowadays. One reason for this is that the geostationary orbit required by this kind of satellites is becoming too crowded. Probably power levels of l0 kW to l00 kW will be the standard and with life duration of 25 years. It is not possible to keep 0.5 kW modules with more than 100 in parallel and therefore higher power modules (5 kW) must be used. A higher bus voltage seems also necessary and keeping a safety limit of 150 V, any voltage below it and above 100 V could meet the needs. In this paper we will propose a topology that fits the application: two soft switched interleaved boost converte…

Bidirectional High-Efficiency Nonisolated Step-Up Battery Regulator

The design and results of a high-efficiency high-power (5 kW) nonisolated bidirectional dc-dc converter is presented. High stability due to minimum phase behavior is an additional benefit of the topology. The converter is a new boost with output filter where input and output inductors are coupled. This converter is useful with any system that needs to charge and discharge backup batteries and can be applied in space, automotive, and telecom power systems.

Assessing Radiation Hardness of SIC MOS Structures

It is widely known that devices based on wide gap semiconductors show potential benefits in terms of saving mass, increasing power densities compared with standard Silicon ones [1]. The higher operating temperatures these components can withstand can also reduce the power budget currently used for cooling down power electronics. These factors are critical in space applications where, for example SiC devices are very promising. However, in this field reliability is a paramount requirement, and radiation conditions can compromise the usage of these new technologies.

Prototyping and Characterization of 1.2KV SIC Schottky Diodes for TWTA Application: The Challenge to Meet the User Specification

SIC based solid state protections switches for space applications

Development and technology maturation of Silicon Carbide (SiC) power transistors over the last 15 years has motivated its study in aerospace systems. When compared with Si devices, superior voltage blocking capacity and the capability of operation at higher temperatures, give important advantages in space power electronics applications, similar to what happens in terrestrial electronics. This paper discusses the use of SiC power transistors for Solid State Power Switches especially addressed to the space segment. Two applications will be covered, the first is the Solid State Shunt Switch, widely used in high power Direct Energy Transfer (DET) photovoltaic power regulators and the second is …

Novel zero-current-transition circuit for three-phase buck rectifiers

ZCT circuits have already been proposed in the past and are becoming more and more popular in high power rectifiers and inverters where bipolar devices have to be used (IGBTs or even BJTs). Although ZCT techniques have already been applied to three-phase boost type topologies, no ZCT circuits have been proposed for three-phase buck-type topologies. The authors propose a new load independent ZCT circuit for a three-phase buck-type rectifier which achieves high noise reduction, voltage stress reduction and zero current transitions to almost all transitions of the rectifier's switches including the additional auxiliary switches.

Dynamic $\mathrm{R}_{\mathrm{ON}}$ evaluation of commercial GaN HEMT under different switching and radiation conditions

This paper focus on the study of dynamic resistance $(\mathrm{R}_{\mathrm{dyn}})$ over commercial Gallium Nitride High Electromobility Transistors (GaN HEMTs) devices. The first part shows a study of the main mechanism causing $\mathrm{R}_{\mathrm{dyn}}$ , showing that depending on the structure, stress time, voltage applied and switching conditions, the $\mathrm{R}_{\mathrm{dyn}}$ can suffer a relevant increase. Also, it is demonstrated how the use of soft-switching conditions can alleviate trapping effects. Finally, due to the interest over these devices for future space applications, the effects of gamma radiation over the $\mathrm{R}_{\mathrm{dyn}}$ has been studied.

Unstable behaviour of normally-off GaN E-HEMT under short-circuit

The short-circuit capability of power switching devices plays an important role in fault detection and the protection of power circuits. In this work, an experimental study on the short-circuit (SC) capability of commercial 600 V Gallium Nitride enhancement-mode high-electron-mobility transistors (E-HEMT) is presented. A different failure mechanism has been identified for commercial p-doped GaN gate (p-GaN) HEMT and metal-insulator-semiconductor (MIS) HEMT. In addition to the well known thermal breakdown, a premature breakdown is shown on both GaN HEMTs, triggered by hot electron trapping at the surface, which demonstrates that current commercial GaN HEMTs has requirements for improving the…

Hydrogen back-up power system with photovoltaic direct energy transfer regulation and interleaved boost for space applicattions

This work details a power conditioning unit for photovoltaic/hydrogen based energy systems in space applications. The power conversion techniques applied are similar to the ones used on photovoltaic/battery space power systems. A direct energy transfer photovoltaic regulator is devised for feeding two outputs; the first output corresponds to the main unregulated battery bus and the second output sets a power path to feed an electrolyser. A modular fuel cell converter completes the system and operates when photovoltaic energy is not available or load demand exceeds the generated photovoltaic power, providing electrical power from a fuel cell. An ancillary battery, located in the main bus, di…

Study of the Audio Susceptibility in Parallel Power Processing With a High-Power Topology

In this paper, the audio susceptibility characteristic of a high-efficiency nonisolated topology that processes only a part of the total power delivery is analyzed. Since the proposed topology presents a direct path from input to output, the effect of the input voltage ripple at the output voltage has been studied. The effect on the audio susceptibility of the values and disposition of the components and the effect of their parasitic elements must be taken into account. Due to this study, the analytical expression of the audio susceptibility and the design criteria to improve it have been obtained.

SiC Based Latching Current Limiter for High Voltage Space Power Distribution Systems

This study presents a novel Latching Current Limiter topology, based on a N-channel Silicon Carbide (SiC) MOSFET as the main switching element. The design has been carried out using only discrete components, without digital controllers. This design has been validated by simulation and with a prototype. Tests have been performed at 1000V, modifying the limitation times, current-limiting values and eventually checking the proper operation of the system.

Bidirectional high-power high-efficiency non-isolated step-up DC-DC converter

This paper presents the results of a high-efficiency high-power (5kW) non-isolated bidirectional DC-DC converter. High efficiency, high stability and simplicity are the main goals, and no galvanic isolation is required. The proposed topology is a new BOOST converter with output filter where input and output inductors are coupled together which can be designed to be a minimum phase system. This topology provides therefore input and output current filtering, reducing noise and need of additional filters. Its bidirectionality reduces mass in many applications like in charge/discharge subsystems and lowers cost and component count. This converter is useful with any system that needs backup batt…

On the use of front-end cascode rectifiers based on normally on SiC JFET and Si MOSFET

The new wide band-gap semiconductor devices provide new properties to be explored. Normally on silicon carbide (SiC) JFET power devices have several advantages, in particular low switching losses and the potential capabilities of high temperature and high reverse blocking voltage. Looking for improving the overall efficiency in power converters, new structures based on these power devices might be studied. In this paper, a cascode rectifier based on normally on SiC JFET is presented and analyzed. This rectification structure can be applied as front-end rectifier stage for ac-dc power converters, increasing the overall efficiency of these topologies. A second cascode rectifier based on silic…

SiC MOSFET vs SiC/Si Cascode short circuit robustness benchmark

Abstract Nowadays, MOSFET SiC semiconductors short circuit capability is a key issue. SiC/Si Cascodes are compound semiconductors that, in some aspects, show a similar MOSFET behaviour. No interlayer dielectric insulation suggests, in theory, Cascode JFETs as more robust devices. The purpose of this paper is to compare the drift and degradation of two commercial devices static parameters by exposing them to different levels of repetitive 1.5 μs short-circuit campaigns at 85% of its breakdown voltage. Short-circuit time has been set experimentally, and longer times result in catastrophic failure of MOSFET devices due to over self-heating. For this purpose, pre- and post-test short circuit ch…

Stability improvement of isolated multiple-output DC/DC converter using coupled inductors

Coupling output inductors is a very popular solution when designing a multiple-output DC/DC system. Space-borne circuits are one of the areas where a custom DC/DC converter design with coupled inductors could be preferred to have a detailed design of all variables. Output voltage regulation can be improved using coupled output inductors on a multiple-output DC/DC converter, and, as demonstrated in this paper, it provides an enhanced stability. This paper presents the small signal analysis of a push-pull converter with seven outputs having all its output inductors coupled together and compares it theoretically to the uncoupled version to demonstrate the stability improvement. The theoretical…

A Comparative Performance Study of a 1200 V Si and SiC MOSFET Intrinsic Diode on an Induction Heating Inverter

This paper presents a comparison of the behavior of the intrinsic diode of silicon (Si) and silicon carbide (SiC) MOSFETs. The study was done for 1200 V Si and SiC MOSFETs. The data sheet from manufacturers shows the characteristics of MOSFET' intrinsic diode when gate source voltage (VGS) is 0 V. There are applications where the MOSFET' intrinsic diode is used while VGS is different than 0 V. One of these applications is induction heating, where depending on the load and the regulation system, the diode can conduct a significant part of the inverter current. In most applications which use the MOSFET' intrinsic diode, the turn ON of the intrinsic diode happens at VGS = 0 V. After a blanking…

Benefits and Drawbacks of A High Frequency Gan Zvzcps Converter

This paper presents the benefits and drawbacks of replacing the traditional Si Mosfets transistors with enhancement mode GaN transistors in a Half-Bridge Zero Voltage and Zero Current Switching Power Switching (ZVZCPS) converter. This type of converters is usually used as Electronic Power Converters (EPC) for telecommunication satellites travelling-wave tube amplifiers (TWTAs). In this study, firstly the converter is theoretically analysed, obtaining its operation, losses and efficiency equations. From these equations, optimizations maps based on the main system parameters are obtained. These optimization maps are the key to quantify the potential benefits of GaN transistors in this type of…

300°C SiC Blocking Diodes for Solar Array Strings

Silicon Carbide 300V-5A Ni and W Schottky diodes with high temperature operation capability (up to 300°C) have been fabricated. This paper reports on the stability tests (ESA space mission to Mercury, BepiColombo requirements) performed on these diodes. A DC current stress of 5A has been applied to these diodes at 270°C for 800 hours. These reliability tests revealed both, degradation at the Schottky interface (forward voltage drift) and at the diode top surface due to Aluminum diffusion (bond pull strength degradation). The use of W as Schottky metal allows eliminating the forward voltage drift producing stable metal–semiconductor interface properties. Nevertheless, SEM observations of the…

Phase Margin Degradation of a Peak Current Controlled Converter at Reduced Duty Cycle

An inner current loop is frequently used in many switching power supplies to achieve higher stability and a good current sharing. Nevertheless, some problems derived from its practical implementation can be encountered. One problem is related to the need of filtering of the sensed current and was discovered by the authors in the implementation of a 500 W converter, when peak current control was applied by sensing the switch current. This paper will demonstrate mathematically that an RC filter not only filters out the noise but also can cause a degradation of the phase margin, especially, if the needed duty cycle is close to zero. The main reason for it is the severe distortion of the curren…

Design of Zero-Ripple-Current Coupled Inductors With PWM Signals in Continuous Conduction Mode

Coupled inductors are widely used in multiple outputs and interleaved dc–dc converters. Also filters often use coupled inductors as their inductive part. A generalized design procedure is proposed in this article focused on current ripple minimization and applicable to coupled inductors exposed to pulsewidth modulation signals and in continuous conduction mode. The design provides a very large inductance for all windings but one. Compared to other designs, it adapts to the existing magnetic properties of the magnetic device changing only the inductance ratio, simplifying the design and manufacturing process. It is based on the equivalent inductance value and its divergences. The only assump…

A Test Circuit for GaN HEMTs Dynamic Ron Characterization in Power Electronics Applications

Wide bandgap devices such as GaN HEMTs are a promising technology in the field of Power Electronics. Due to the physical properties of the Gallium nitride and the device design, they can outperform their Silicon counterparts for the design of highly efficient power switching converters. However, its design should face certain effects that can diminish its performance. One of such effect is the degradation mechanism known as dynamic onresistance (dynamic RON,), being its mitigation one of the main objectives in the design of the device. In this paper, a circuit is proposed for assessing if this effect is present in GaN transistors in power electronics applications. The circuit allows testing…

Zero Ripple Current with Coupled Inductors in Continuous Conduction Mode under PWM Signals

This article presents a generalized analysis to explain current ripple of an $m$ windings coupled inductor with a given coupling factor $k_{ij}$ for each pair of windings and then studies more in detail its use in the continuous conduction mode and with pulsewidth modulated signals. To determine the current ripple, a generalized expression of the equivalent inductance of each winding is calculated, including the influence of voltage unbalance. In the ideal case, the equivalent inductance shows that the current ripple can only become $m$ times smaller than that with uncoupled inductors. But in the unbalanced case, some divergences of the equivalent inductance appear that are responsible for …

High Temperature SiC Blocking Diodes for Solar Array

This paper presents the results of an experimental investigation of the performance of 300V-5A Silicon Carbide Ni and W Schottky diode operating in the range between -170°C to 270°C. We have developed these diodes as blocking diodes, for solar cell array protection in order to fulfill the BepiColombo mission specifications. An electro-thermal characterization has been performed taking into account the harsh condition of the mission (high temperature range and electrical stress). The destructive and non-destructive tests have assured that the designed SiC diodes are able to support the electro-thermal limits. A reliability test has also been performed to investigate the stability of forward …

Using Pulse Density Modulation to Improve the Efficiency of IGBT Inverters in Induction Heating Applications

This paper analyses a high power (50 kW), high frequency (150 kHz) voltage fed inverter with a series resonant load circuit for industrial induction heating applications which is characterized by a full bridge inverter made with IGBT and the power control based on pulse density modulation (PDM). This power control strategy allows that the inverter works close to the resonance frequency for all output power levels. In this situation zero-voltage switching (ZVS) and zero-current switching (ZCS) conditions are performed and the switching losses are minimized. The results are verified experimentally using a prototype for induction hardening applications. A comparative study between the PDM and …

Multi-pulse characterization of trapping/detrapping mechanisms in AlGaN/GaN high electromobility transistors

GaN high-electro mobility transistors (HEMTs) are among the most promising candidates for use in high-power, high-frequency, and high-temperature electronics owing to their high electrical breakdown threshold and their high saturation electron velocity. The applications of these AlGaN/GaN HEMTs in power converters are limited by the surface trapping effects of drain-current collapse. Charge-trapping mechanisms affect the dynamic performance of all GaN HEMTs used in power switching applications. This study analyzes the dynamic resistance of GaN HEMTs and finds that the effects of dynamic resistance can be suppressed by controlling switching conditions and on-off cycles.

Dynamic behavior analysis and characterization of a cascode rectifier based on a normally-on SiC JFET

Test bench for coupling and shielding magnetic field

This paper describes a test bench for training purposes, which uses a magnetic field generator to couple this magnetic field to a victim circuit. It can be very useful to test for magnetic susceptibility as well. The magnetic field generator consists of a board, which generates a variable current that flows into a printed circuit board with spiral tracks (noise generator). The victim circuit consists of a coaxial cable concentric with the spiral tracks and its generated magnetic field. The coaxial cable is part of a circuit which conducts a signal produced by a signal generator and a resistive load. In the paper three cases are studied. First, the transmitted signal from the signal generato…

A high-efficiency regulation technique for a zero-voltage zero-current power switching converter

This paper describes the application of a new regulation technique to a resonant converter that features zero-voltage (ZV) and zero-current (ZC) switching and works at constant frequency and duty cycle. The regulator utilizes the concept of regulating only a percentage of the total power in a bidirectional manner, thus allowing the converter to be optimized for both mass and efficiency. The proposed regulation technique has a wide range of applicability to almost all types of power converters or inverters that utilize a transformer to produce an isolated output. By using the concept of addition or subtraction of AC voltages, a fully regulated output voltage is achieved. The resultant effect…