Four-quadrant Switch Research Articles

Active and reactive power control of grid‐connected single‐phase asymmetrical eleven‐level inverter

In recent times, multilevel inverters (MLIs) have become very popular for commercial and industrial applications. Here, an eleven-level inverter and its power flow control are presented. The presented topology has a lesser component count than other existing topologies, thus reducing the devices and overall cost of the inverter. This inverter comprises six bidirectional switches, two DC sources, one four-quadrant switch, and two capacitors for the voltage divider circuit. The conduction modes and corresponding switching states of the presented eleven-level inverter are shown in detail. Further, the apparent power control of the presented inverter under grid-connected operation is discussed, which provides simultaneous active and reactive power control over the power injected into the grid. Switching and conduction losses are calculated for 3 and 6 kVA grid injected power at 0.8 power factor lagging. The obtained results show that the total harmonic distortion (THD) of the inverter output voltage and grid current is 12.10% and 0.23%, respectively, under 6 kVA power transfer conditions. The real-time analysis is also carried out for 3 and 6 kVA power transfer conditions for the presented eleven-level inverter to validate the active and reactive power flow control.

Enhanced Fault-Tolerant Robust Deadbeat Predictive Control for Nine-Level ANPC-Based Converter

Deadbeat model predictive control (DB-MPC) is one of the advanced promising control methods for power converters thanks to its simplicity, high steady-state performance and fast dynamic response. However, the high sensitivity to parameter mismatch and the difficulty of handling multiple control targets are problematic issues in DB-MPC. This work presents an improved robust DB-MPC for a new nine-level ANPC-based inverter. This inverter requires a low number of power devices compared to other single dc-source inverters. Only nine active switches and two discrete diodes are used to generate a nine-level voltage waveform. Without the need for weighting factors, the proposed DB-MPC method tackles three control goals; current control, flying capacitors (FCs) stabilization and dc-link balance, which saves the laborious effort of adjusting the weighting factors in the traditional finite control set MPC (FCS-MPC) method. Moreover, an effective dc-link balancing scheme based on power flow control is proposed and integrated into the FCs control objective. To enhance the control robustness, an EKF-based estimator is designed to identify the system parameters online. In addition, the proposed DB-MPC scheme allows the considered inverter to continue operating with the generation of five levels in the failure condition of the four-quadrant switch, improving the fault tolerance of the inverter. The developed DB-MPC method is experimentally verified in steady-state and transient operation. To demonstrate the excellent performance of the presented DB-MPC scheme, experimental comparisons with other popular MPC methods are performed.

Current-Source Inverter Integrated Motor Drives Using Dual-Gate Four-Quadrant Wide-Bandgap Power Switches

Four-quadrant (FQ) switches that have both bidirectional current and reverse-voltage blocking (RVB) capabilities are appealing candidates for use in current-source inverters (CSI) to significantly reduce the switch conduction losses. However, the FQ characteristics of these switches can create problems during switching events by causing transient overcurrent pulses that damage the inverter. Commutation methods for FQ switches in CSI topologies that address these challenges are presented in this article. Several key aspects of the performance and implementation of these commutation methods are explored for a high-power density 3 kW integrated motor drive incorporating both a current-source active rectifier and inverter stage that has been developed using these FQ switch methods. Experimental results demonstrate the benefits of implementing these commutation methods in CSIs that use FQ switches. The benefits include substantial efficiency improvement compared to the conventional CSI implemented with series power diodes as well as reduced mass and volume of passive components due to the high switching frequency (100 kHz).

Overview of Power Electronic Switches: A Summary of the Past, State-of-the-Art and Illumination of the Future.

As the need for green and effective utilization of energy continues to grow, the advancements in the energy and power electronics industry are constantly driven by this need, as both industries are intertwined for obvious reasons. The developments in the power electronics industry has over the years hinged on the progress of the semiconductor device industry. The semiconductor device industry could be said to be on the edge of a turn into a new era, a paradigm shift from the conventional silicon devices to the wide band gap semiconductor technologies. While a lot of work is being done in research and manufacturing sectors, it is important to look back at the past, evaluate the current progress and look at the prospects of the future of this industry. This paper is unique at this time because it seeks to give a good summary of the past, the state-of-the-art, and highlight the opportunities for future improvements. A more or less ‘forgotten’ power electronic switch, the four-quadrant switch, is highlighted as an opportunity waiting to be exploited as this switch presents a potential for achieving an ideal switch. Figures of merit for comparing semiconductor materials and devices are also presented in this review.

Packed E-Cell (PEC) Converter Topology Operation and Experimental Validation

This paper proposes a novel single-dc-source multilevel inverter called Packed E-Cell (PEC) topology to achieve nine levels with noticeably reduced components count, while dc capacitors are actively balanced. The nine-level PEC (PEC9) is composed of seven active switches and two dc capacitors that are shunted by a four-quadrant switch to from the E-cell, and it makes use of a single dc link. With the proper design of the corresponding PEC9 switching states, the dc capacitors are balanced using the redundant charging/discharging states. Since the shunted capacitors are horizontally extended, both capacitors are simultaneously charged or discharged with the redundant states, so only the auxiliary dc-link voltage needs to be sensed and regulated to half of the input dc source voltage, and consequently, dc capacitors' voltages are inherently balanced to one quarter of the dc bus voltage. To this end, an active capacitor voltage balancing integrated to the level-shifted half-parabola carrier PWM technique has been designed based on the redundant charging/discharging states to regulate the dc capacitors voltages of PEC9. Furthermore, using the E-cell not only reduces components count but also the proposed topology permits multi ac terminal operation. Thus, five-level inverter operation can be achieved during the four-quadrant switch fault, which confers to the structure high reliability. The theoretical analysis as well as the experimental results are presented and discussed, showing the basic operation, multi-functionality, as well as the superior performance of the proposed novel PEC9 inverter topology.

Solid-State Transformer Architecture Using AC–AC Dual-Active-Bridge Converter

Modern development of semiconductor power-switching devices has promoted the use of power electronic converters as power transformers at the distribution level. This paper presents an ac-ac dual-active-bridge (DAB) converter for a solid-state transformer. The proposed converter topology consists of two active H-bridges and one high-frequency transformer. Four-quadrant switch cells are used to allow bidirectional power flow. Because power is controlled by the phase shift between two bridges, output voltage can be regulated when input voltage changes. This paper analyzes the steady-state operation and the range of zero-voltage switching. It develops a switch commutation scheme for the ac-ac DAB converters. Experimental results from a scaled-down prototype are provided to verify the theoretical analysis.

Cost-effective sustain driver employing a new four-quadrant switch cell for AC plasma display

A new energy-recovery circuit (ERC) for the plasma display panel (PDP) using a switched transformer is proposed. The proposed ERC is very cost effective due to the reduction of device count and circuit complexity such as highside gate drivers and diodes in the resonant path. Also, the leakage inductances of the transformers are used as resonant inductors for soft-switching operation of the main switches. The operation and performance of the proposed energy recovery circuit were validated through waveform and power efficiency measurement tests with prototype hardware in 200 kHz switching frequency.

Microprocessor based Symmetrical Multipulse Modulation in a Three-Phase Improved Power Quality AC-DC Converter with Four-Quadrant Switch Realizations

A three-phase a.c. controller using power MOSFETs operating in high- frequency chopping mode has been developed fabricated and tested with resistive load. The microprocessor based firing scheme is used to test the four-quadrant switch realizations. The output voltage is smoothly varied using symmetrical multipulse modulation by varying the duty cycle, and the relevant experimental results are furnished. The harmonic analysis of the chopped wave is made in terms of the number of pulses per cycle and pulse width. For same values of power factor and per unit output voltage, it can be concluded from the test results that the proposed scheme has much lower values of lower order harmonics as compared to conventional thyristor phase control. The computed results have been experimentally validated.

Control of high-frequency AC link electronic transformer

An isolated high-frequency link AC/AC converter is termed an electronic transformer. The electronic transformer has size and cost advantages over a conventional transformer because of high-frequency operation of the magnetic core. Of the various topologies of electronic transformer, the high-frequency AC link electronic transformer achieves high-frequency AC power transformation without a DC link. The circuit uses the standard H-bridge, one on either side of the high-frequency transformer. A novel PWM scheme is proposed, which symmetrically delays and advances the phase of the left and right legs of the front-side converter with respect to the output-side converter. The proposed scheme introduces freewheeling sub-periods, which results in zero voltage switching in the output-side converter. The electronic transformer as an AC automatic voltage regulator (AVR) offers distinct advantages over a conventional servo voltage stabiliser in terms of size and speed of response. The AVR application is discussed and experimental results of a 500 VA AVR are presented. A four-quadrant switch presents difficulties in turning off inductive load current because of the absence of a freewheeling path in the switch. A biasing circuit is proposed to convert the potentially lossy switching transition into lossless transition. Simulation and experimental results with the biasing circuit are presented.

Comprehensive investigations of high voltage non-punch-through double gate-injection enhanced gate transistor

Comprehensive numerical simulations were performed to investigate a novel double gate-injection enhanced gate transistor (DG-IEGT). The DG-IEGT structure eliminates the need for trading off the forward voltage with the switching loss. Because DG-IEGT is a four-quadrant switch, it is capable of conducting currents and blocking voltages in both directions. This capability enables DG-IEGT to be used in many applications to replace multiple switches and diodes. DG-IEGT, therefore, is close to an ideal power switch and should be developed as a next generation device to replace high power insulated gate bipolar transistor.

Applications of a four-quadrant multiplier

Applications demonstrating the performance of a four-quadrant multiplier and signal switch in controlled-feedback modes are presented. The range of possible applications of the circuit is greatly increased by considering this mode of operation over previously suggested applications.