Switching Transistors Research Articles

Efficient Control of Induction Motor Current in a Frequency-Controlled Electric Drive

An analysis of methods for controlling the current of an asynchronous electric motor in a frequency-controlled electric drive is performed. The disadvantages of a control system with relay current controllers that provide system operation in the “current corridor” mode are shown. Such disadvantages as increased thermal losses in the transistors of the frequency converter are caused by the unstable switching frequency of the motor current. The relevance of the principles of current control using the predictive model to form control actions in the frequency converter circuit with relay controllers is noted. A method of current control in an asynchronous electric drive is considered that makes it possible to stabilize the switching period of the inverter power switches when controlling the current in the motor. To obtain this result, it is proposed to influence the width of the hysteresis loop of the relay current controllers and form it depending on the parameters of the load circuit. The required accuracy of the current control is maintained. The structure of the control system is proposed, in which the considered method is implemented. A key element of the system is a computing unit that generates signals that set the required width of the hysteresis loop of the relay controllers. The method of predicting changes in the controlled current after the next switching of transistors in the inverter of the frequency converter of the electric drive is the analytical basis of the calculations. Analytical expressions providing the calculations necessary for the computing unit operation are presented. The effect of applying the relay current controllers with variable hysteresis in the control system of a frequency-controlled electric drive is shown.

Optimization of Operating Parameters for Stable and High Operating Performance of a GDI Fuel Injector System

In this study, a novel injector driving circuit was developed to achieve the regulation of fuel injection quantity and to work with the engine control system in a vehicle. The main purpose of the proposed injector driving circuit is to control the quantity and timing of fuel injection within the gasoline direct injection (GDI) fuel injector system. In this paper, a mathematical state model of a high-pressure (H.P.) fuel injector system is derived and the improved Taguchi method is proposed to define the optimal operating parameter settings of a fuel injector system. The experiments on fuel injection quantity were performed to achieve the requirements of the injector driving circuit. The fuel quantity sprayed from a fuel injector system under these control parameters was analyzed by leading the design of experiments. The S/N and β slopes were analyzed to determine their optimal control settings. The H.P. injector driving circuit developed was designed to drive the fuel injector and spray the injected quantity of fuel into the flask following the optimized control factors. The experimental results demonstrate that the H.P. fuel injecting system exhibits better and more stable operating performance, to assure the accurate injection quantity for the GDI injector, and it was also realized with low cost metal oxide semiconductor field effect transistor (MOSFET) switches.

A solid-state pulse generator based on multilayer ceramic capacitors and insulated gate bipolar transistors.

A solid-state pulse-forming network (PFN) module was designed using multilayer ceramic capacitors (MLCCs). In addition, an all-solid-state pulse generator was fabricated with a Blumlein line that consisted of two PFN single lines and an insulated gate bipolar transistor (IGBT) switch array. This generator was integrated on printed circuit boards (PCBs). The stage capacitors of the PFN were composed of MLCCs connected in series and parallel. To obtain a compact structure, folded, copper-clad wires were used as interstage inductors. The copper-clad wires were structurally optimized to reduce coupling between adjacent interstage inductors. A relatively fast rising waveform edge was obtained using an IGBT gate-boosting circuit and magnetic switch technology. A square-wave pulse with a rise time of 27 ns, a voltage of 5 kV, a width of 120 ns, a maximum repetition rate of 100 Hz, and an evaluated lifetime of 109 pulses was obtained on a load of 6.6 Ω. With its compact size, fast rise time, and long lifetime, the fabricated pulse generator can be used as a component in linear transformer drivers or Marx generators.

An induction voltage adder with MHz repetition rates and nanosecond duration based on printed circuit board stacked Blumlein lines.

By utilizing the radio-frequency metal-oxide-semiconductor field-effect transistor switch, the multi-stage stacked printed circuit board Blumlein lines, and the induction voltage adder, a voltage generator with MHz repetition rates and nanosecond duration was designed and fabricated. The shunting current of the multi-stage stacked Blumlein lines, which consists of the coupling current at the load ends and the leakage current at the switch ends, is clarified. The circuit simulation and experiment of the three-stage stacked Blumlein lines are carried out; the result shows that the experiment and simulation agree well. The five-stage IVA prototype is designed for generating voltage pulses of ∼10 kV in amplitude and 8-11 ns in duration with MHz burst repetition rates. The voltage generator with MHz repetition rates and nanosecond duration demonstrated an important application prospect to reduce the electron beam initial emittance of the high energy accelerator.

Design of a GaN-Based Interleaved Nine-Level Flying Capacitor Multilevel Inverter for Electric Aircraft Applications

Multilevel inverters such as the flying capacitor multilevel inverter (FCML) hold large potential benefit in applications where the size and weight of the inverter is constrained. This article presents the design and implementation of an inverter module that incorporates two individual nine-level FCML single-phase inverters in an interleaved design. Each inverter utilizes GaN field-effect transistors (FETs) switching at 100 kHz for an effective inductor ripple frequency of 800 kHz. The implementation features an innovative dual-sided integrated switching cell layout, which decreases the commutation loop inductance of the inverter and allows fast switching with minimal ringing, while also enabling efficient double-sided cooling. The switching cell layout is particularly well suited for high-voltage applications, as creepage and clearance requirements can be easier met compared to single-sided solutions. The effectiveness of the approach is demonstrated in a hardware inverter prototype intended for driving low-inductance electric machines for future electric aircrafts. The 1000 $\mathbf {V_{dc}}$ to 380 $\mathbf {V_{ac,rms}}$ , 6-kW prototype achieves a peak efficiency of 98.6% and a peak power density of 15 kW/kg.

Optimal Design and Performance Evaluation of Dual-Capacitor Switching (DCS) Quench Protection System for Superconducting Magnet

In recent years, a new quench protection system using capacitor and switches has been announced to rapidly extract energy from high temperature superconducting (HTS) magnets. When a quench occurs, the quench protection system activates four metal oxide-semiconductor field-effect transistor switches in sequence, and the energy stored in the magnet is extracted by a capacitor to an external resistor. To verify the feasibility of the proposed dual-capacitor switching (DCS) quench protection system, DCS system was tested using a small-scale coil with a 3.3 mH self-inductance. The experimental results show that the energy extraction of the magnet is faster than the quench protection system using a conventional dump resistor. However, as the system is sensitive to the capacitance, inductance, and four resistances, it is necessary to analyze and optimize the design parameters for an application to various magnet systems. In this study, a modified DCS system is introduced to remove the constraints of capacitance, and the effect of all the design parameters on DCS protection performance is analyzed. The optimal design of modified DCS protection system for the best performance is determined. The performance of the system is also evaluated by applying a design that is optimized for the scale-up HTS coil with a 30 mH self-inductance.

Iron Loss Minimization Strategy for Predictive Torque Control of Induction Motor

Today’s modern control strategies of an induction motor (IM) drive require a power source with an adjustable output voltage frequency and amplitude. The most commonly used converter topology is a two-level voltage-source inverter (VSI). However, the utilization of a VSI introduces additional voltage and current distortion, which leads to additional power losses in the machine’s magnetic circuit. Both the transistor switching frequency and the type of the inverter control determine the total harmonic distortion (THD) of the motor’s phase currents. In this paper, the influence of the inverter DC-link voltage on the iron losses of an IM controlled by a predictive torque control (PTC) is presented. It is shown that if the IM drive operates below the rated speed, it is possible to modify the PTC algorithm to reduce the additional iron losses caused by the non-harmonic inverter output voltage. The control of the DC-link voltage is achieved by using a silicon-controlled rectifier. Experiments were conducted on a 5.5 kW IM controlled by PTC, and the results are compared against a sinusoidal voltage supply created by a synchronous generator.

Model Predictive Direct Duty-Cycle Control for PMSM Drive Systems With Variable Control Set

Finite control set model predictive control has received extensive attention because of its excellent dynamic performance; however, it still needs to be studied in terms of torque ripples reduction and parameter robustness. To reduce the steady-state torque ripples and maintain the appropriate antiparameter perturbation ability, in this article, we propose a model predictive direct duty-cycle control (MPD2C) strategy based on “variable control set (VCS).” In the proposed strategy, the direct mapping relations between the electromagnetic torque, flux, and three-phase duty cycles have been established by exploring the dual relationship of vector synthesis and duty cycles. On this basis, the novel predictive model and VCS that uses the three-phase duty cycles as the key variable are constructed. Finally, the proposed strategy determines the three-phase duty cycles from VCS by employing a two-stage optimization mechanism, which means the proposed strategy can generate virtual vectors with multiple insulated gate bipolar transistor (IGBT) switching patterns. Then, the high-precision torque and flux adjustment would be achieved. The experimental results show that VCS-MPD2C has excellent static and dynamic control performance, acceptable execution efficiency, and relatively good parameter robustness.

Inkjet-Printed Molybdenum Disulfide and Nitrogen-Doped Graphene Active Layer High On/Off Ratio Transistors.

Fully inkjet-printed device fabrication is a crucial goal to enable large-area printed electronics. The limited number of two-dimensional (2D) material inks, the bottom-gated structures, and the low current on/off ratio of thin-film transistors (TFTs) has impeded the practical applications of the printed 2D material TFTs. In the search for TFTs with high current ratios, we introduce a stable and efficient method of nitrogen-doped graphene (NDG) ink preparation for inkjet printing by liquid-phase exfoliation. The NDG thin film is print-stacked with molybdenum disulfide (MoS2) by multiple printing passes to construct a MoS2–NDG stack. We demonstrate top-gated fully inkjet-printed MoS2–NDG transistors with silver drain, source, and gate electrodes, and a barium titanate (BaTiO3) dielectric. A 100% inkjet-printed MoS2–NDG vertical 2D active heterostructure layer transistor with a current on/off ratio of 1200 is exhibited. The results may lead towards the development of all-printed 2D material-based transistor switches.

The use of acoustic emission elastic waves as diagnosis method for insulated-gate bipolar transistor

The article describes research into the use of acoustic emission elastic waves (AE) for diagnosing insulated-gated bipolar transistors (IGBTs). Currently used in many modern shipboard power electronic systems, IGBTs are crucial components required to operate with extreme reliability. The acoustic emission elastic waves method was used to determine the acoustic signals of switching transistor and can be used to monitor early stages of damage. Transistor diagnostics makes use of selected frequency descriptors of AE and appropriate signal analysis.

Application of a microcontroller in automatic electrical domestic changeover system

The design, development, and simulation of an automatic Electrical Mains Changeover System (EMCS) using a PIC microcontroller (μC) has been presented in this study. The system consists of an 18-pin DIP package enhanced flash microcontroller PIC16F84A with a 4 MHz crystal used as the main processor, two switching transistors, two relays, and a Low Voltage Power Supply (LVPS). The electrical mains control signal output at RB0 and RB2 of PortB actuate two switching transistors which drive two relays to operate the loads depending on the availability of mains or backup power source. An assembly language program based on MPLAB IDE has been developed to control the operation of the system. The design and verification of the PIC μC based EMCS in the Proteus 8 simulation platform have been completed successfully.

Dimensional scaling of high-speed printed organic transistors enabling high-frequency operation

Printed electronics has promised to deliver low-cost, large-area and flexible electronics for mass-market applications for some time; however, so far one limiting factor has been device performance. Over the last decade, great progress has been made in terms of materials, processing and printing resolution for printed transistors. In this article, we review dimensional scaling of printed organic thin-film transistors, which has enabled high-frequency operation. We review different device architectures that require different dimensions to be scaled with accompanying tradeoffs in performance and complexity. Various printing methods have been used to print scaled transistors. Inkjet and gravure printing have seen the greatest improvements. We will focus on gravure printing here as it not only enables high-resolution features but also high-speed printing for low-cost manufacturing. Operating voltage has been scaled down less aggressively due to difficulties with scaling down the thickness of printed gate dielectrics. The performance of organic semiconductor materials has also improved substantially. When processing the semiconductor, the scaling of other device dimensions needs to be considered to optimize performance. Based on these advances, transistor switching frequency has increased dramatically over the last decade with several reports of high-speed printed inverters operating at high kHz to low MHz frequencies, which are promising results for emerging applications of printed electronics.

A High Reliability Sense Amplifier for Computing In-Memory with STT-MRAM

In the era of big data, massive data requires processing efficiently. However, the limited data bandwidth between the memory and the processor in conventional computer systems could not meet the requirement of data transferring. Computing in-memory has been considered an effective solution to address this problem. In this paper, based on the spin transfer torque-magnetic random access memory (STT-MRAM), a computing in-memory architecture with as few peripheral circuits as possible is proposed. This computing in-memory architecture gives the specific reference cell so that two rows in one array can be activated simultaneously to perform bitwise logic operations, such as OR/NOR and AND/NAND. In addition, with technology scaling down, STT-MRAM suffers from high sensitivity to process variation, which results in more device mismatch in a sense circuit. Additionally, the negative bias temperature instability (NBTI) seriously affects the life of PMOS transistors used in a sense circuit. In this paper, a high-reliability sense amplifier for computing in-memory with STT-MRAM is proposed. By using two self-enabled switching transistors, the proposed sense amplifier not only can decrease the NBTI effect on PMOS transistors but also can achieve a low sensing error rate. Using a CMOS 40[Formula: see text]nm design-kit and an accurate compact model of the STT magnetic tunnel junction (MTJ), mixed transient and statistical simulations have been present to demonstrate the functionality and performance of the proposed circuits.

Statistical Method of Estimating Semiconductor Switching Transition Time Enabling Condition Monitoring of Megawatt Converters

Detection of insulated-gate bipolar transistor (IGBT) switching transition time ( $t_{\text {tr}}$ ) is a promising temperature-sensitive electrical parameter (TSEP) for condition monitoring of IGBT power modules in converters for wind turbines. The accuracy required on $t_{\text {tr}}$ detection is in nanoseconds, which typically requires precision timing circuitry, or analog-to-digital converter (ADC) rates in hundreds of megasamples per second (MS/s). A method of calculating the statistically estimated switching transition time ( $\hat {t}_{\text {tr}}$ ) is proposed in this article. During multiple switching transitions of an IGBT, the IGBT collector–emitter voltage (vce) may be sampled with sample rates in sub-MS/s rates, yet with statistical accuracy on estimated $\hat {t}_{\text {tr}}$ in nanoseconds. A standalone converter monitoring unit (CMU), which samples vce and IGBT current ( $i_{c}$ ), was mounted in the converter of a multi-megawatt (MW) field test wind turbine. The proposed method is validated by testing it on field data from the CMU and by testing it on synthetically generated data. The proposed method is an enabler for low-cost monitoring of converters for wind-turbine field applications.

Uporedna analiza prekidačkih gubitaka energije u galijum-nitridnom HEMT i silicijumskom MOSFET tranzistoru

The subject of this paper is the mutual comparison of switching energy losses in cascode gallium nitride HEMT and silicon "superjunction" MOSFET transistor, both designed for a maximum operating voltage of 650 V. For the purpose of analysis the transistor switching characteristics, the double pulse test method was implemented. Detailed computer simulation models developed in programs of the SPICE family were used. Data on transient turn -on and turn-off processes were generated by LTspice simulation tool, in a wide range of drain currents, using two different gate resistance values for driving the transistors under test. The obtained results indicate superior switching characteristics of gallium nitride devices in comparison to silicon components, especially during the high drain current transistor operation. During the one transistor switching cycle, the total energy losses in the GaN HEMT were simulated, for a drain current of 30 A, and found to be five to eight times lower when compared to tested Si MOSFET transistor.

CMOS Backplane Pixel Circuit With Leakage and Voltage Drop Compensation for an Micro-LED Display Achieving 5000 PPI or Higher

Micro-displays based on micro-LEDs are becoming more and more attractive in AR/MR (Augmented/Mixed Reality) applications. A display size of 0.5 to 0.7-inch is preferred, with 5,000 PPI (Pixel Per Inch) or higher. Due to this pixel density and size, a CMOS (Complementary Metal-Oxide-Silicon) backplane is an ideal solution to drive these pixelized micro-LEDs. As the required pixel size gets smaller, the design of the appropriate pixel circuit becomes more challenging. The simplest 2T1C (2 transistors & 1 capacitor) pixel circuit has potential problems, due to the leakage current of the switch transistor and the voltage drop on the matrix array layout. In this paper, a pixel circuit is proposed as a solution to overcome these two issues. Our simulation results show that the variation of the driving current to the LED is improved by 95 %, and the IR drop error rate is around 2.2 % compared to the 2T1C circuit. The test results also show that the error rate of IPIXEL for the whole region of display is under 2.5 %. This work is verified using a test chip implementation with 180 nm CMOS process technology.

A Tiny Complementary Oscillator With 1/f 3 Noise Reduction Using a Triple-8-Shaped Transformer

This letter presents a triple-8-shaped transformer-based complementary oscillator. It features tiny area, wide tuning range (TR), electromagnetic compatibility (EMC), and low flicker phase noise (PN), combining the merits of both $LC$ -tank and ring oscillators. We identify that after suppressing the second-harmonic voltage by the complementary operation itself, the third-harmonic current entering the capacitive path is now the main cause of asymmetry in the rising and falling edges, leading to the $1/f$ noise upconversion. By tuning the capacitance ratio between gate and drain nodes of the switching transistors, it mitigates the third-harmonic voltage and introduces a specific gate–drain phase shift, reducing the $1/f^{3}$ PN. Fabricated in 22-nm FDSOI CMOS, the prototype occupies an area of 0.01 mm2 and achieves $1/f^{3}$ PN corner of 70 kHz, PN of −110 dBc/Hz @1MHz and Figure-of-Merit (FoM) of −182 dB at 9 GHz, 39% TR, resulting in the best FoM with normalized TR and area (FoMTA) of −214 dB@1 MHz.

Comparison between GaN and SiC for power switching transistor application

Semiconductor has been widely used in industry ever since its invention and has experienced three generations. However, there are still many problems existing in the third generation semiconductors industry such as making process and cost. This paper mainly discusses the differences between GaN and SiC in material properties and fabrication process. Material properties include band-gap, critical field strength, carrier mobility, and thermal conductivity. For fabrication process, GaN is normally used homoepitaxy approach and SiC is used heteroepitaxy approach. The details in these two approaches are given in the paper.

Impedance Detection Based on Ripple Analysis and Current Sharing Control in DC Microgrid

In the operation of DC micro grid, the uniform load distribution is beneficial to the stable operation of the system and prolongs the service life of the system. In order to solve the influence of line impedance on traditional droop control in DC micro-grid, an impedance detection method based on ripple analysis and the structural characteristics of the DC micro-grid system is proposed. The high-frequency harmonic component of microgrid output current and voltage is mainly from the transistor switching frequency. By using the Fourier transform to analyze the high-frequency harmonic component of the voltage and current detected by the converter, the impedance information is obtained, and then the droop control is compensated base on it. In this paper, the compensation method is extended to the application of multiple devices in parallel. This method does not directly operate the system, so it has done no harm to the power quality. Finally, the feasibility of the proposed method in normal working conditions and its effectiveness in the case of communication interruption and load change is verified by RT-LAB hardware in loop experiment.

Design of a High Accuracy PSR CC/CV AC–DC Converter Without Auxiliary Winding

A high accuracy ac–dc converter without auxiliary winding has been proposed in this article. The converter adopts primary-side regulation (PSR) topology, sampling output voltage and current from primary inductance, then adjusting switching frequency and primary peak current of the power converter to regulate output. By switching the main power transistor and the auxiliary switching transistor alternately on and off , and using base charge storage effect to generate driving voltage, the converter charges chip-powering capacitor by primary-side current, instead of auxiliary winding. Compared to the traditional three-winding topology, the proposed converter not only achieves higher performance, but also eliminates one winding, which means fewer external components are used, transformer becomes simpler, and system cost is lower. The control chip was implemented in NEC 1- μ m HVCMOS process, and a 5 V/1 A prototype has been built to verify its feasibility. Experimental results show that the control chip can be powered perfectly, and the deviations of output voltage and current are within ±1.3% and ±2.5% under different input and load conditions, whereas maximum conversion efficiency can reach a level of 78.9%.