Power electronic converters are essential part of hybrid fuel cell automotive application systems. The converter needs to provide high-voltage ratio for a wide range of input voltage. In addition, the converter should have high efficiency for a wide range of duty cycle control range. A four-phase floating interleaved boost converter (FIBC) is analysed and a small-signal AC model using an averaged pulse-width modulation (PWM) switch technique is used for supporting the feedback controller and aiding a frequency response design. The small-signal AC model as well as the current controller are validated by simulation and evaluated by experimental results. The proposed converter has competitive device ratings, the total inductance volume and weight is decreased, current ripple is minimised and converter efficiency and reliability are improved. Proof of concept of the proposed topology is demonstrated through an experimental prototype.

For grid-connected inverters, switching harmonics can be effectively attenuated through an LCL-type filter. In order to suppress resonance and guarantee good performance, many strategies (e.g. active damping (AD), harmonic resonant control, repetitive control and grid feedforward) have been proposed. However, the wide variation of grid impedance value challenges system stability in practical applications. The aforementioned methods need to be investigated. This study evaluates the applicability of each part of the overall control in a weak grid case with the use of a stability criterion. It has been demonstrated that the feedback-based AD control can work well in a wide range of grid conditions. However, the resonant and repetitive control methods meet constraints. The grid feedforward method brings in an extra positive feedback path, and consequently results in high harmonics or even instability. Finally, a recommendation for system design has been presented. Simulations and experiments have been provided to verify the analysis.

A new voltage balancing algorithm is introduced for cascaded H-bridge rectifiers. This kind of converter is made of a series connection of H-bridge cells with separate dc-links. The proposed balancing algorithm will regulate the voltage of all dc-links to the desired reference value, even if the attached loads are very different. The input current is also programmed to be sinusoidal and has low distortion, while the switching frequency is kept low at 1 kHz. In addition, the input power factor can be controlled. The simulation and experimental results are presented to confirm the validity of the proposed algorithm.

The increasing need for higher efficiency, weight and volume reduction in embedded applications is a starting point of this study which focuses on a pre-sizing methodology of power converters based on virtual prototyping tools to avoid physical prototypes. From a general point of view, the mutualisation of a three-phase inverter with the help of a power sharing system is introduced. The proposed design approach optimises N inverters and a {one inverter + N-power sharing system} topologies based on a generalised modelling and a virtual prototyping tool. The presented results based on a 3 kW–270 V DC bus application show that in addition to the switching frequency and the ambient temperature, the number of sequential loads is also a key of the optimisation parameters. Therefore the proposed methodology based on an optimisation process allows the power designers to compare N inverters and {one inverter + N-power sharing system} as a function of the load number N.

This study presents an implementation of composite observer-based control algorithm in three-leg voltage source inverter (VSI)-based distribution static compensator (DSTATCOM) in four-wire power distribution network. This control algorithm is used for extraction of load fundamental current components of polluted load currents. These components of load currents are used for estimation of reference source currents to generate the gating pulses of insulated gate bipolar transistors  used in VSI of DSTATCOM. This control algorithm is implemented for mitigation of power quality problems such as reactive power compensation, harmonic elimination and load balancing under linear/non-linear loads. The performance of DSTATCOM is found quite satisfactory for these unbalanced loads.

Z-source inverters are inverters with buck–boost capability that traditional inverters cannot match. Despite this ability, present Z-source topologies are burdened by some limitations such as chopping input current, high-voltage stress and poor spectral performance at high gain. To improve their performances, a number of asymmetrical transformer-based embedded Z-source inverters are proposed. Through theoretical derivation and experiments, the proposed inverters have been shown to draw a smooth input current and produce a high gain by varying the transformer turns ratio n. The range of variation for n depends on the inverter topology chosen, which in turn depends on the application under consideration.

The development of a current controller with inherent integral action for a full-bridge boost rectifier is presented. The main control objectives are to achieve dc output voltage regulation and near-unity power factor in the presence of unknown load. The stability analysis of the current-controlled rectifier system is carried out using Floquet theory. Some experimental results are also presented to verify the effectiveness of the control method.

This study presents the performance of a direct torque control (DTC)-based induction motor drive (IMD) with improved power quality converter at the front end. It is designed, modelled, simulated in MATLAB/simulink platform and implemented in hardware using a digital signal processor (DSP). An improved power quality converter known as Vienna rectifier is used in the system to mitigate the power quality problems at the utility interface in the DTC-IMD. The proposed Vienna rectifier is a three switch converter to improve the power quality in terms of reduced total harmonic distortion of ac mains current, power factor correction and dc-link voltage regulation. The performance of the proposed system is validated experimentally using a DSP. The performance of the system is tested for step change in input reference speed and the load torque and it is found that the power quality indices conform to IEEE-519 standard under all operating conditions.

An improved zero-voltage-switching (ZVS) phase-shift full-bridge converter with self-regulating auxiliary current is proposed. ZVS of lagging-leg switches can be achieved in whole conversion range because of the introduced active auxiliary circuit. Meanwhile, the auxiliary circuit that features simple control of the auxiliary switches has no effect on the main power transferring path and the auxiliary energy stored for ZVS of lagging-leg can be regulated by the load current without significantly increasing conduction loss over the entire load range. The operation principle of the proposed converter is discussed in detail and further simplification of the proposed topology is suggested. The design method of key parameters is carefully depicted. Finally, the operation and performance of the proposed converter are verified on a 1 kW/54 V, 100 kHz prototype.

This study proposes control and design methods for a current source united power-quality conditioner (CS-UPQC). Unipolar modulation and parameter design methods are proposed for the series CS converter. The proposed modulation method doubles the equivalent switching frequency, which makes it possible to reduce the filter size and improve the control dynamics. Modified repetitive control schemes are presented for the voltage and current compensation strategies, which provide large open-loop control gains at the integral multiple of the fundamental frequency and guarantee good harmonics compensation performance. A fault current limiting scheme is also presented, which limits the fault current effectively by utilising the large DC link inductor of the CS-UPQC. Simulation results in Matlab/Simulink are presented to clarify the theory and feasibility of the proposed approaches.

A hybrid passive-active damping solution with improved system stability margin and enhanced dynamic performance is proposed for high power grid interactive converters. In grid connected active rectifier/inverter application, line side LCL filter improves the high frequency attenuation and makes the converter compatible with the stringent grid power quality regulations. Passive damping though offers a simple and reliable solution but it reduces overall converter efficiency. Active damping solutions do not increase the system losses but can guarantee the stable operation up to a certain speed of dynamic response which is limited by the maximum bandwidth of the current controller. This paper examines this limit and introduces a concept of hybrid passive-active damping solution with improved stability margin and high dynamic performance for line side LCL filter based active rectifier/inverter applications. A detailed design, analysis of the hybrid approach and trade-off between system losses and dynamic performance in grid connected applications are reported. Simulation and experimental results from a 10 kVA prototype demonstrate the effectiveness of the proposed solution. An analytical study on system stability and dynamic response with the variations of various controller and passive filter parameters is presented.

The availability of limited voltage vectors in a conventional direct torque control drive fed from a two-level inverter causes torque and current ripples. In this study, a new torque ripple reduction technique with a modified look up table incorporating a larger number of synthesised non-zero active voltage vectors is proposed to overcome the limitations of the conventional and duty ratio control switching strategies. The voltage vector selection criteria in the proposed technique are based to prevent the stator flux demagnetisation during the low-speed operation with significant reduction in torque and current ripple. The proposed switching strategy is investigated through simulation and experimentally validated on a test drive.

The authors propose a novel sliding-mode variable structure controller for cascade STATic var COMpensator (STATCOM), which integrates the direct feedback linearisation control for the balanced system and the individual phase instantaneous current tracking control for the unbalanced system, to achieve a versatile STATCOM controller. It can adapt automatically to various distribution system conditions. Based on the degree of system unbalance, the authors design a switching function to make the STATCOM work reliably with satisfactory performance, when the serious voltage sag occurs or the distribution system enters serious asymmetrical condition. The authors also propose a hierarchical DC-link voltages balance control strategy. The authors build a detailed ± 10 MVar STATCOM model with power system CAD and electro magnetic transient in DC system (PSCAD/EMTDC) and validate the effectiveness and advantage of the proposed control strategy with the simulation study.

Recent works of different authors have shown that the use of intercell transformers  in interleaved inverters bring many improvements to this kind of parallelism. However, even though a balanced current distribution is necessary and not guaranteed by the converter itself; just a few of those studies are focused on the modelling and control of the inverter. Moreover, the fact that the paralleled modules are coupled and that the control signals are not updated simultaneously have not been considered yet. In this way, the current paper takes those facts into account and proposes a simple procedure for modelling and control a single-phase interleaved inverter. A mathematical analysis, some simulation and experimental results are shown in order to prove the simplicity and effectiveness of the proposed procedure.

A quadratic boost converter with high DC gain to step up the voltage of a standard photovoltaic panel up to 400 V is analysed. First of all, a comparative analysis among boost, quadratic boost and cubic boost reveals that the quadratic boost exhibits the best trade-off between duty ratio range and converter efficiency. A hysteretic comparator is employed as a modulator to ensure the converter operation with high values of the duty ratio without risk of modulation saturation. A two-loop sliding-mode control is used to regulate the output voltage. An internal loop controls cycle by cycle the input current whose reference is established by an outer loop that processes the output voltage error by means of a proportional-integral compensating network. The measured results in a 100 W prototype operating in continuous conduction mode of average values, ripples, frequency and efficiency for different equilibrium points are in good agreement with the theoretical predictions.

An interleaved series resonant converter with fixed frequency pulse-width modulation (PWM) is presented to achieve load current sharing, ripple current cancelation, zero-voltage switching (ZVS) for power switches and zero-current switching (ZCS) for rectifier diodes. Two three-level DC converters with clamped diodes and flying capacitor are adopted to share load current. The voltage stress of power switches is clamped at one-half of DC bus voltage. The interleaved PWM scheme is used to control two converters in order to reduce the output current ripple and size of output capacitor. The series resonant tank in three-level PWM converter is adopted to realise ZVS turn-on for all power switches andZCS for rectifier diodes. Thus, the switching losses of active switches are reduced and the reverse recovery losses of rectifier diodes are eliminated. The fixed frequency PWM operation is adopted to regulate output voltage, so that the drawback of a wide range of switching frequency in the conventional series resonant converters is overcome. Finally, experiments based on a scale-down prototype are provided to verify the effectiveness of the proposed converter.

In this study, implementing a dynamic quick response with high-frequency feedback control (HFFC) of the deformable constant on-time (COT) control for Buck converter on-chip is proposed. The concept uses the HFFC to filter V _out at the load transient to change the on-time width dynamically, preventing V _out from dropping markedly. Finally, 12 V input voltage, 3.3 V output voltage and 60 W output power with the HFFC are implemented to achieve a dynamic quick response for the integrated circuit of the proposed constant frequency COT for Buck converter. Experimental and SIMPLIS simulation results are compared to verify the viability and superiority of the proposed approach.

A single-stage multi-port DC–DC converter topology is proposed. It can accommodate arbitrary number of input sources and output loads, and employs a single inductor. The voltage of each output port can be less than the minimum input voltage or exceed the maximum input voltage. Power regulation can be provided for the input ports in addition to providing voltage regulation for the output ports. The steady-state and dynamic characteristics of the converter are analysed and a control scheme is proposed. Hardware measurements and numerical switch-level simulations verify the analytical results.

Driving power metal-oxide semiconductor field-effect transistor at high frequency may induce significant switching losses, which have a great proportion in total power losses. Especially in the case of higher temperature, switching losses increased tangibly. A novel temperature adaptive gate driver with low power consumption in a high-temperature environment is proposed for switched-mode power supply by the temperature compensation technique. It has been realised to decrease the switching losses in wide scope temperature, and cannot sacrifice performance of the electromagnetic interferences, by regulating di/dt and dv/dt of switching curve in high temperature. A 0.25 μm, 40 V bipolar-CMOS-DMOS (BCD) process technology is utilised and experimental circuits and results are then presented. Compared with the conventional gate driver, the turn-on loss and turn-off loss of the temperature adaptive gate driver can be reduced, respectively, by 17% and 22%. At present, it has been used in an AC–DC converter to improve work efficiency.

Owing to high oil prices and the efforts to reduce greenhouse gases according to the United Nations Framework Convention on Climate Change, there has been active research and development on environmentally friendly, high-efficiency vehicles. In developing the system design and specifications of an environmentally friendly vehicle, various simulations have been performed on the different components and the overall system. Although a precise modelling of each part and the system as a whole is necessary for an accurate simulation, detailed modelling of a high-capacity battery system – which directly affects the performance of an environmentally friendly vehicle – is difficult to achieve owing to the non-linear electrochemical properties of the battery. In this study, an electrochemical impedance measurement technique is used to implement a battery cell model, upon which a battery system model for environmentally friendly vehicles that takes into account the ancillary components of the battery pack is developed. And we used an actual battery system that requires complex and difficult modelling owing to non-linear and irreversible properties of the battery. In addition, to verify the developed battery system model, we used models implemented for other vehicle components and systems to construct a hardware-in-the-loop simulation of a battery reflecting an actual driving environment.