In this study, a signal impulse transmission function is investigated which provides high insulation voltage capabilities for IGBT drivers devices. This electrical insulation is achieved with a printed circuit board (PCB) and classical copper windings. Two ferrite cores are added to improve the magnetic coupling effect and thus decrease the impulse current maximum value in the primary side. The electronic circuit involves a series resonant topology in the primary side and a parallel one in the secondary side. The classical electronic components lead potentially to cost-effective solutions. However, so as to optimise the proposed system, a design methodology based on virtual prototyping tools is carried out. The simulation results presented on a Pareto front are analysed with the help of propagation delay and average power consumption. Moreover, measurement results with a 1.6 mm PCB are compared with simulation ones. Finally, the proposed solution and the methodology design are clearly accurate and suitable for power electronic designers and especially for IGBT driver devices designers.

A full digital deadbeat controller is proposed for the speed loop to obtain better dynamic response performance in permanent magnet synchronous motor servo system. Given an expected target error function and speed command in Z-domain form, according to the deadbeat zero-pole configuration rules, the digital controller is derived to make the current command output stable in several sampling periods and the speed response also becomes stable without ripples. To reject disturbance from the load variation, an estimation method, based on model reference adaptive system through Popov's hyper stability criteria, is presented to identify online the moment of inertia and load torque. The two quantities are essential for the speed loop to achieve adaptive control by load compensation. The simulation and experimental results reveal the effectiveness of the proposed speed controller.

Multilevel inverters have attractive features which make them one of the most popular fields of investigations. They can operate in high power and high voltage conditions. Multilevel inverters generate output voltage with high quality and low harmonic contents. As the number of output voltage levels increases, the quality of the output voltage is improved leading to reduction of the filtering requirements. However, multilevel inverters have the disadvantage of increased power electronic switches. This leads to higher cost, size and complication. Some advanced topologies have been introduced to reduce the number of power electronic switches, unfortunately, most of these topologies need high voltage switches on their structure making them unsuitable for high voltage conditions. In this study, an innovative topology for multilevel inverter is proposed which reduces the number of switches considerably without using high voltage switches. The proposed topology is a general topology which can be extended for any number of voltage levels. The authors call this topology as cross-switched multilevel inverter. The simulation results obtained in PSCAD/EMTDC as well as the experimental results verify the proposed topology.

High-frequency AC (HFAC) power distribution system (PDS) has recently received more and more attentions and has a broad application from electric vehicle to Micro-grid. The resonant inverter is commonly used to provide the fixed frequency output for point of load (POL). However, the control and implementation of high-frequency resonant inverter is complicated to provide good steady and dynamic performance, because of the worse operating circumstance from parameter uncertainties, inaccuracy model, as well as load and line perturbations. Although H_∞ robust controller has already been widely examined, the feedback voltage controller designed by μ-synthesis accurately provides more effective analysis and design framework to achieve robust stability and robust tracking performance. In this study, the perturbations and control target are analysed to construct the unstructured and structured uncertainties for resonant inverter. A new μ-based controller is designed by μ-synthesis to testify its tracking performance under the given perturbations, and the robust performance of proposed controller is theoretically evaluated by μ-analysis. The prototype of simulation and experiment are implemented with a rated output power of 120 W and operation frequency of 25 kHz. The results prove its superiority over traditional PI and H_∞ controllers for HFAC power source constructed by LCLC resonant inverter.

Source switching circuit with low-gate-driving loss in high-voltage buck light emitting diode (LED) driver is proposed in this study. Source switching circuit comprises of a high-voltage power metal-oxide semiconductor field-effect transistor (MOSFET) (HVMOS) and a low-voltage power MOSFET (LVMOS) in series, a capacitor and a Zener diode. By switching the HVMOS by different source voltage and constant gate voltage, it recycles gate charges of HVMOS to reduce gate-driving loss. Gate charges are recycled in the capacitor when LVMOS is turning off, and can be reused when LVMOS is turning on. This circuit also provides a new power feeding route for control chip, and power consumption is relatively low on the proposed route. The power feeding route also improves power efficiency. With a 12 W LED load, the experiment shows that the efficiency of the proposed driving circuit is improved by 3.7% with 156 V input voltage and 4.8% with 326 V input voltage compared with the converter using single HVMOS.

This study presents a single-stage electronic ballast for the high-intensity-discharge (HID) lamp with high-power factor. The presented ballast consists of a discontinuous-conduction-mode operated dual-boost converter to achieve input current shaping, and a high-frequency combined with a low-frequency square-wave-driven half-bridge-type inverter for supplying the HID lamp with low-frequency square-wave sources. The attractive features of the proposed ballast are high-power factor (> 0.99), low total harmonic distortion of input utility-line current (< 10%), high efficiency (> 90%), cost-effectiveness and freedom from acoustic resonance. The operational principles, design guidelines and a design example are included in this paper. A prototype ballast circuit has been successfully implemented and tested for supplying three different brands of 70W HID lamps operating with 110 V-root-mean-square input utility-line voltage. Satisfactory experimental results demonstrate the functionalities of the proposed ballast.

This study presents a unified time-domain formulation of switching frequency for hysteresis current controlled AC/DC and DC/AC grid connected converters. It is shown that the generalised expression of switching frequency obtained can be used for any mode of operation of the converter based on phase relation between the reference AC current and grid voltage. The presented analysis provides information of maximum, minimum and average switching frequencies for all modes of the converter operation. The analytical results derived under different configurations are verified through the experimental results obtained using FPGA-based implementation of the controller for the converter. The applications of the results are shown on the three different single-phase systems operating in current control mode: (i) static synchronous compensator, (ii) boost rectifier and (iii) grid interface of wind-turbine system. The results of switching operations in these applications are verified using simulation studies performed in power systems CAD/electromagnetic transients including DC (PSCAD/EMTDC) software.

In this study, a single-stage pickup with zero-voltage turn-on to reduce the switching loss is proposed for parallel resonant compensated contactless power transmission systems (CPTS). A bidirectional switch composed of two back-to-back connected active switches is integrated to regulate the output voltage. The relationship between the output voltage and the duty ratio of the bidirectional switch is derived and verified. To evaluate the validity and performance of the proposed pickup circuit, a 500 W prototype CPTS is constructed. The experimental results show that the power conversion efficiency of the proposed pickup is about 95%. Moreover, compared with common two-stage pickup, the number of required passive components in the proposed topology is reduced. The resulted volume of proposed pickup is also reduced which is more suitable for space-limited applications.

In this study, a grid simulator based on a back-to-back inverter topology with resonant controllers is presented. The simulator is able to generate three-phase voltages for a range of amplitudes and frequencies with different types of perturbations, such as voltage sags, steady-state unbalanced voltages, low-order harmonics and flicker. The aim of this equipment is to test the performance of a given system under such distorted voltages. A prototype of the simulator, consisting of two inverters connected back-to-back to a 380 V three-phase grid and feeding a micro-grid composed of two-inverter interfaced distributed generators and a critical load was built and tested. A set of experimental results for linear purely resistive loads, non-linear loads and current-controlled inverters is presented to prove the capabilities of the simulator. Finally, a case study is presented by testing a micro-grid.

This study deals with observability problems and control of the parallel multicell chopper. In the area of strong currents with high switching frequencies, new structures based on the combination of components have been developed. Among them, the authors find the parallel multicell converters that the authors studied in this study. This type of choppers is a DC/DC static power converter which has an output current equals to n (n is the number of cells) times the source current. After recalling the dynamical equations of the converter, its hybrid dynamical behaviour and properties are highlighted. This particular hybrid system induces new and difficult observability problems, such problem can be tackled by a new observability concept [the Z(T_N )-observability]. However, for a large number of switching cells in parallel, the complexity of the system makes it impossible to predict the transient behaviour of the converter and therefore all predimensioning. The main disadvantage of this type of converter is the imbalance branches of current with increasing number of cells. Therefore modelling and control with Petri net is proposed to solve the problems of imbalanced of currents and the voltage output regulation with variation of the load. The authors approaches are attested by several numerical simulations considering noisy measurements and load variations.

Parallel connection of converters has become a popular method of improving efficiency. This study first presents a design technique for a buck converter with two parallelly connected power modules (PMs), where one PM is designed with large current ripple for high efficiency. This study then demonstrates an active current ripple cancellation technique, where the current waveform of the second PM is shaped to be the exact opposite to that in the first PM, to reduce the current ripple as seen by the output capacitor. The factors that affect the overall efficiency in a parallel connected converter and the calculation of the parameters that determine the effectiveness of the ripple cancellation are reported. A prototype parallel converter is designed based on the proposed converter design technique and the current ripple seen by the output capacitor is successfully reduced by 66% with the proposed ripple cancellation technique, under different line and load conditions.

In this study, an adaptive non-linear controller is designed for DC–DC buck/boost converter which is robust and stable against converter load changes, input voltage variations and parameter uncertainties. The proposed controller is developed based on input–output linearisation using an adaptive backstepping approach. The controller can be applied in both continuous and discontinuous conduction modes (CCM and DCM). Owing to non-minimum phase nature of buck/boost converter, the output voltage of this converter is indirectly controlled by tracking the inductor reference current. The inductor reference current is generated by a conventional PI controller. Using a MATLAB/Simulink toolbox and a stand-alone TMS320F2810 digital signal processor from Texas Instruments, some simulations and practical results are presented to verify the capability and effectiveness of the proposed control approach.

In this study, fault-tolerant operation of multilevel cascaded H-bridge (CHB) inverters is presented and a novel switching strategy based on space vector modulation is proposed. A faulty power switch in high power converters can lead to expensive downtime, loss of productivity and increased costs. Various power switch faults and their influence on space vector diagram of CHB inverters are investigated. In the event of a fault, the output voltage of inverter is reduced and redundant switching states are used to generate balanced line-to-line voltages. By adding some devices to the basic structure, CHB inverter will operate with maximum achievable output voltage. Simulation and experimental results are shown for a five-level CHB inverter to validate the proposed modulation technique.

In this study, the backstepping control (BSC) design for a high-performance inverter with the functions of stand-alone and grid-connected power supply is developed so that distributed generation units can operate individually or in a micro-grid mode. In the stand-alone power-supply mode, the output ac voltage can supply to ac loads. In the grid-connected power-supply mode, the goal of power management can be achieved by controlling the amplitude and direction of the output current in the inverter. As a result, the proposed high-performance inverter with the BSC scheme has the output voltage with a low total harmonic distortion in the stand-alone power-supply mode and the output current with a high-power factor in the grid-connected power-supply mode to provide an ac output with high-performance power quality. The effectiveness of the proposed high-performance inverter with the BSC is verified by experimental results of a 3 kW prototype, and the merit of the proposed BSC scheme is indicated in comparison with previous proportional-integral control, proportional-resonant control and adaptive total sliding-mode control strategies.

In this study, the non-linear dynamics of a two-stage cascaded-boost converter, which is a popular choice, for solar energy systems is investigated. The stability of the system is studied with the aid of non-linear state equations derived from an averaged continuous model. Analysis of the describing autonomous equations reveals that the system loses stability via supercritical Hopf bifurcation. Extensive computer simulations are performed to capture the system's dynamic behaviour and demarcate the bifurcation boundaries. Furthermore, the possibility of subcritical Hopf bifurcation for variation in input voltage is also examined. Trajectory and Poincaré section before and after the bifurcation are shown. Experimental results are also provided to confirm the observed bifurcation scenario.

A novel dual active clamp forward topology with interleaved series input parallel output (ISIPO) structure is proposed here. The ISIPO active clamp forward converter enables the converter cells to share the input voltage and output current. The interleaved operation can diminish the output current ripple in the output capacitor. The output capacitance of switching devices and the resonant inductance are utilised to realise the resonance at the transition interval of switches such that the zero-voltage-switching operation for all switches can be achieved. Moreover, the energy stored in the transformer leakage inductance is recycled such that the voltage stresses of switching devices are reduced. All these features make the proposed converter suitable for the DC–DC converters with high input voltage, high output current and high-efficiency applications. The operating principle and design considerations are provided in detail. Finally, experimental results based on a 240 W(12 V/20 A) prototype with an input voltage of 400 V are presented to verify the theoretical analysis and circuit performance.

This study re-introduces a hybrid multilevel converter that is capable of operating independent of load power factor and modulation index plus is applicable to medium- to high-voltage application. These features are achieved by adopting a new modulation strategy that utilises third harmonic subtraction in order to: increase the modulation index linear range, have a smaller capacitor size and smaller footprint, have zero net power exchange between the cell capacitors, and the load is guaranteed for all operating conditions. This study establishes an optimal magnitude of third harmonic to be subtracted by the H-bridge cells to ensure proper converter operation. The validity of the presented modulation strategy and capacitor voltage balancing are confirmed by simulation and experimentation on a scaled-down model and prototype. The scalability of the hybrid multilevel converters to high-voltage application is demonstrated using simulation, including start-up and shut down without the need for auxiliary circuitry.

Input voltage unbalance causes input current waveform degradation of matrix converter because of the lack of reactive component in dc link. To reduce the harmonic content of input current, dynamic input current modulation methods based on space vector modulation strategy have been presented in some works. This study proposes two improved double line voltage synthesis (DLVS) strategies for matrix converters. Both strategies apply the dynamic input current modulation methods to DLVS aiming at improving input and output waveforms at the same time. Besides, simplicity is another advantage of the methods proposed in this study. Phase detection of input current modulation vector is eliminated, which reduces the calculation time of control algorithm. Numerical simulations and experiments with a 10 kW prototype are carried out. The results are given to verify the feasibility and effectiveness of the proposed strategies.

This study presents a simple and a generalised space vector pulse-width modulation scheme for a neutral point clamped multi-level inverter as well as cascaded inverter of any level. This modulation algorithm implements the online generation of desired switching states and their sequences through generalised expressions without any predetermined stored data in a memory look-up table. The proposed algorithm also incorporates the concept of reference vector and on-time modification combined during the over-modulation region for any level of inverter. Performance of the proposed modulation algorithm is tested experimentally through a digital signal processor-based controller for a five-level cascaded inverter with very low execution time that does not depend much on the level of inverter. The simulation waveform and the harmonic analysis of the voltage at different modulation index are presented and these are verified with the experimental results.

This research paper proposes the shunt active filter (SHAF), which is used to improve the power quality of the electrical network by mitigating the harmonics with the help of Types-1 and -2 fuzzy logic controllers (Types-1 and -2 FLC) using different fuzzy membership functions (MFs). To carry out this analysis, active and reactive current (I_d –I_q ) control strategy is chosen. Three-phase reference current waveforms generated by proposed scheme are tracked by the three-phase voltage source converter in a hysteresis band control scheme. The performance of the proposed control strategy has been evaluated in terms of harmonic mitigation and DC-link voltage regulation under various source conditions. To maintain DC-link voltage constant and to generate the compensating reference currents, the authors have developed Types-1 and -2 FLC with different fuzzy MFs (trapezoidal, triangular and Gaussian). The I_d –I_q control strategy with proposed Type-2 FLC is able to eliminate the uncertainty in the system and SHAF gains outstanding compensation abilities. The detailed real-time results using real-time digital simulator are presented to support the feasibility of proposed control strategy.