Switch Control Circuit Research Articles

Design and implementation of pulse width modulation gate control signals for two-level three-phase inverters

The switching control circuit in a DC to AC inverter is the critical part that is applied to control the power transistors insulated-gate bipolar transistor (IGBTs) and metal-oxide semiconductor field-effect transistor (MOSFETs). This paper proposes a high-performance and low-cost pulse width modulation (PWM) control signal with a 120º phase shift circuit for a two-level three-phase inverter. Typically, a PWM signal with a 120º phase shift for three-phase inverters is generated with the help of analogue components with more complicated designs and power losses or by using a microcontroller with necessary programming or coding. The proposed solution is to design a 120° three-phase shift circuit based on D flip-flops and the 555-timer to generate the clock signal for the flip-flop input in addition to the dead-time control circuit. The proposed circuit is controlled by one square wave signal as an input signal to generate six output PWM control signals at 50 Hz to operate six MOSFETs in the three-phase inverter. Simulation results in power simulation software PSIM and PROTEUS simulation tools are used to verify the proposed circuit. Hardware implementation of the proposed circuit and three-phase inverter is carried out to validate the performance of the proposed design.

A Family of IPT Battery Chargers With Small Clamp Coil for Configurable and Self-Sustained Battery Charging Profile

To self-sustain the constant current (CC) output to constant voltage (CV) output transition for inductive power transfer (IPT) chargers, the clamp coil assisted IPT battery chargers are better than the existing solutions due to the merits of no additional switching components, sensors, and control circuits. However, the clamp coil of these IPT chargers is bulky and hard to design, as the mutual inductances between the clamp coil and the main coupler coils are significant to the output performances. To facilitate the small clamp coil in the transmitter, this paper proposes a family of IPT battery chargers with a proper secondorder compensation network on the secondary side. The output thresholds of the IPT charger with the proper compensation can be readily configured to cope with the desired charging profile, and the clamp coil can be designed very small to decrease the corresponding cost and size. In addition, the proposed threecoil IPT charger still features automatic and smooth CC-to-CV transition to eliminate wireless communication, near unity power factor to minimize voltage-ampere (VA) ratings, soft switching to improve transfer efficiency, and open-circuit protection during CC charging. An experimental prototype of a 48 V/2.5 A battery charger is built to verify the analysis.

Regional Stability of Switching Control Circuit Systems with Multiple Equilibria

This paper investigates the stability of systems of multi-equilibrium switching circuits. For a first-order switching circuit system with two subsystems containing unique equilibria and different equilibria, we first establish a sufficient condition for the stability of the region of the multi-equilibrium first-order switching circuit system, and then complete the proof of its stability by means of a general solution of the system state. Secondly, for the second-order multi-equilibrium switching circuit system, the sufficient condition for the stability of the second-order multi-equilibrium switching circuit system is given, and the feasibility of the theorem is finally proved by drawing on existing research results and related sufficient conditions. The conclusions obtained show that the system of first- and second-order multiple equilibria switching circuits in the region is regionally stable after the corresponding switching paths.

A Dual-Mode Control Scheme to Improve Light Load Efficiency for Active-Clamp Flyback Converter

A novel dual-mode control scheme is proposed in this paper that permits the active-clamp flyback (ACF) converter to operate in both the quasi-resonant (QR) mode under light load and the active-clamp mode under medium or heavy load. The mode transition is performed based on the external dual-mode control circuit. In addition, the proposed converter incorporates a new QR mode valley switching (VS) control circuit that reduces switching loss in the main switch by achieving VS. Under medium to full load, the proposed converter becomes an ACF converter designed to achieve zero-voltage switching (ZVS), which reduces switching losses in both power switches. The proposed dual-mode control ACF converter has the following advantages: (1) compared with conventional ACF converters, the proposed ACF converters minimize switching losses by combining VS and ZVS; (2) under light load conditions, the frequency-limiting QR control mechanism is used to avoid disadvantageous switching losses caused by high switching frequencies. The 65 W ACF converter prototype with a DC 155 V input and a DC 19 V/3.42 A output under 65 kHz switching frequency was implemented. The experimental results demonstrate the feasibility of the proposed control scheme. The efficiency of the proposed converter reached 79% at a load of 3.5 W, which is 11% higher than the conventional ACF converter.

A Low-Power High-Efficiency Adaptive Energy Harvesting Circuit for Broadband Piezoelectric Vibration Energy Harvester

Existing piezoelectric vibration energy harvesting circuits require auxiliary power for the switch control module and are difficult to adapt to broadband piezoelectric vibration energy harvesters. This paper proposes a self-powered and low-power enhanced double synchronized switch harvesting (EDSSH) circuit. The proposed circuit consists of a low-power follow-up switch control circuit, reverse feedback blocking-up circuit, synchronous electric charge extraction circuit and buck-boost circuit. The EDSSH circuit can automatically adapt to the sinusoidal voltage signal with the frequency of 1 to 312.5 Hz that is output by the piezoelectric vibration energy harvester. The switch control circuit of the EDSSH circuit works intermittently for a very short time near the power extreme point and consumes a low amount of electric energy. The reverse feedback blocking-up circuit of the EDSSH circuit can keep the transmission efficiency at the optimal value. By using a charging capacitor of 1 mF, the charging efficiency of the proposed EDSSH circuit is 1.51 times that of the DSSH circuit.

Design and Implementation of a Wireless Iidentification Device

This system takes AT89 series single-chip microcomputer as the core, which constitutes the two ends of the wireless identification device: transponder and reader. The whole system is mainly composed of the smallest single-chip microcomputer system, binary code preset circuit, carrier generation circuit, analog switch control circuit, high-frequency amplifying filter circuit, display circuit and other modules. The transponder part uses the AT89S51 single-chip microcomputer to control the serial output of the preset binary code, uses the active crystal oscillator to generate the carrier wave, and outputs the modulated signal through the analog switch. The reader part amplifies the modulated signal with high frequency, filters the signal, and controls the light-emitting diode to turn on and off to display the identification signal and the four-bit binary code after the acquisition and processing by the single-chip microcomputer. This design realizes the functions of identification, binary code preset and display, single power supply, transmission distance greater than 5cm, time less than 5s, accuracy rate greater than 80%, power less than 2W, transponder storage and other functions.

Research and Design of Switch Control Module of Railway Signaling Based on Power Electronics Technology

According to the characteristics of railway operation, and studying the main structure of the interlocking system, a set of railway switch control module suitable is designed by using power electronic technology and modular design. This paper studied on the new-type pure electronic control of switch control circuit. The reliability and safety of the railway switch control module are analyzed by scientific means. Through field tests, it fully proves that the module has the advantage characteristics of small volume, fully functional, and stable performance etc. In a word, it has strong engineering practical value and conforms to the development trend of railway technology.

Analysis of the Vibration Suppression of Double-Beam System via Nonlinear Switching Piezoelectric Network

In this paper, a method to suppress the vibration of a double-beam system with nonlinear synchronized switch damping on the inductor via a network (SSDI-net) is proposed. Unlike the classical linear piezoelectric shunt damping, SSDI-net is a nonlinear piezoelectric damping. A double-beam system with SSDI-net was simplified to a lumped parameter electromechanical coupling model and analyzed by using the multi-harmonic balance method, at first with alternating frequency–time techniques (MHBM/AFT). Then, a new lower-power autonomous switching control circuit board was designed, based on SSD technique, and vibration control experiments using a double-beam system with an SSDI network are conducted, to verify the validity of the proposed analysis method and its calculation results. The nonlinear switching piezoelectric network proposed in this article can increase the voltage inversion factor. Furthermore, future applications of this switching piezoelectric network technology in the vibration suppression of bladed-disk structures in aero engines can reduce the number of switches by at least half and obtain almost the same damping effect.

Experimental verification for improved phase‐disposition PWM of three‐phase five‐level diode‐clamped inverter

SummaryThis paper focuses on the design and practical implementation of the effective and improved switching modulation and filter circuits for a three‐phase five‐level diode‐clamped inverter. The proposed switching modulation circuits illustrate the three‐phase control signals, carrier signals, and signals for drive circuits. The paper presents also an efficient control and drive circuits, which are used to operate the power switches (power MOSFETs). An improved analog dead‐band circuit is practically analyzed and implemented to minimize the overlapping periods of any two complement power switches and consequently reduce the noise/spikes caused by those overlapping periods. The proposed improved switching modulation circuit is verified by simulation results along with their analogous experimental results for the switching modulation, control circuits, and power circuits.

Open Defect Detection Not Utilizing Boundary Scan Flip-Flops in Assembled Circuit Boards

An electrical interconnect test method is proposed to detect and locate open defects occurring at interconnects between integrated circuits (ICs) and a printed circuit board. The test method does not utilize boundary scan flip-flops. It is based on a quiescent supply current that is made to flow through an interconnect under test by embedding a test circuit into the ICs. The circuit consists of MOS switches for each input pin of the ICs and its switch control circuit. SPICE simulations are used to examine whether open defects at the interconnects can be detected using this method. The simulation results indicate that the following defective interconnects are detected in addition to defective ones modeled as an open-circuit fault at a test speed of 25 MHz: defective interconnects modeled as a resistor of 150 $\Omega $ generating an additional propagation delay of 482 ps and as a capacitor of 4 pF generating an additional propagation delay of 128 ps and no logical changes. Testability of open defects using this test method is also examined experimentally by prototyping an IC in which the test circuit is embedded. The experiments indicate that a resistive interconnect of $150~\Omega $ and a defective one modeled as a capacitor of 2.2 nF can be detected by the test method at a test speed of 0.5 MHz.

A research on pulse power source with high instantaneous energy density for coupled mechanical ultrasonic-electrical pulse treatment

The high strength and high hard metal materials such as nickel-based superalloy have been widely used because of their excellent properties. If the gradient nanostructures are prepared on their surfaces, their properties will be further improved and their application will be expanded. In this paper, a coupled mechanical ultrasonic-electric pulse (CMUEP) treatment method is presented and its special pulse power source with high instantaneous energy density is developed. The power supply includes main circuit, gate turn-off thyristor (GTO) control circuit, switch control circuit, display circuit, etc. The CMUEP treatment of nickel-based superalloy is carried out by using this power source. The results show that grains with the average diameter of 25.8nm are prepared on Inconel 718 surface, which can further improve the properties of the high strength and high hard metal materials and broaden their application.

Flexible and Super-Sensitive Moisture-Responsive Actuators by Dispersing Graphene Oxide into Three-Dimensional Structures of Nanofibers and Silver Nanowires.

Smart actuators with excellent flexibility, sensitive responsiveness, large-scale bending-deformation, and rapid deformation-recovery performance have been sought after by researchers. Two-dimensional graphene oxide (GO) is considered as an ideal candidate for humidity-responsive actuators because of its excellent moisture sensitivity. Herein, a flexible membrane-based actuator was prepared by evenly dispersing GO sheets into a three-dimensional network formed by one-dimensional PVA-co-PE nanofibers (NFs) and silver nanowires (AgNWs). The three-dimensional interlaced pore structure of the AgNWs/NFs/GO composite membrane ensured its larger contact area (19.33 m2/g), faster moisture exchange rate, and large bending deformation under moisture stimulation. In addition, a new explanation for the spatial distribution of adsorbed water molecules and their actuating effect on the bending behaviors of composite membranes is proposed. The adsorbed water lies between the interlayer and surface layer of the composite membrane. The interlayer water molecules make the film volume expand, resulting in a large bending angle of the membrane. On the other hand, the water on the surface layers of the membrane only leads to the change in film weight, having little effect on the bending behavior. Moreover, to make the soft actuator more practical and multifunctional, a conductive AgNWs-NFs/GO bilayer membrane-based actuator was prepared by layered spraying of a AgNW on the NFs/GO membrane, which can be directly used in switching control circuits. The novel flexible membrane-based actuators are of great significance for the soft robot and intelligent control systems in the future.

A Novel Active Cell Balancing Circuit and Charging Strategy in Lithium Battery Pack

A novel, active cell balancing circuit and charging strategy in lithium battery pack is proposed in this paper. The active cell balancing circuit mainly consists of a battery voltage measurement circuit and switch control circuit. First, all individual cell voltages are measured by an MSP430 microcontroller equipped with an isolation circuit and a filter circuit. Then, the maximum cell voltage difference is calculated by subtracting the minimum cell voltage from the maximum cell voltage. When the maximum cell voltage difference exceeds 0.05 V, the balancing action starts to carry on. The MSP430 microcontroller output controls signals to close the switches corresponding to the battery cell with the maximum voltage. At this time, the balancing charge power performs a balancing charge for other batteries, except for the one that is switched on. In addition, a three-stage balancing charge strategy is also proposed in this paper to achieve the goal of speedy charging with balancing action. In the first stage, a 0.5 C balancing current is used to perform pre-balanced charging on all battery cells until the maximum cell voltage difference is less than 0.05 V, which is required for entry to the second stage of charging. In the second stage, constant current charging of 1 C, coupled with 0.2 C balancing current charging is carried out, until the maximum battery cell voltage reaches 4.2 V, which is required for entry into the third stage of charging. In the third stage, a constant voltage charging is coupled with 0.2 C balancing current charging, until the maximum battery cell voltage reaches 4.25 V, which is required to complete the balancing charge. The imbalance of power between the battery cells during battery pack charging, which reduces battery charging efficiency and battery life, is thus effectively improved. In this paper, a six-cells-in-series and two-in parallel lithium battery pack is used to perform a balancing charge test. Test results show that the battery cells in the battery pack are capable of quickly completing a balancing charge under different initial voltages, the maximum voltage difference is reduced to within the range of 0.05 V, and the total time required for each balancing charge is approximately 3600 s.

A Novel Sensor for Vibration Frequency Measurement With Piezoelectric Kinetic Energy Harvesting

In this paper, converting the kinetic energy into electrical energy by tracking the vibration frequency automatically, a vibration sensor with energy harvesting capability for the real-time measurement of vibration frequency is proposed and verified for the first time according to the authors’ knowledge. The frequency measurement and energy conversion are achieved by the aid of a piezoelectric energy harvesting device (PZ EHD). A highly efficient energy harvesting circuit based on Bias-Flip technique is adopted to harvest power efficiently from the PZ EHD. An adaptive switch control circuit is used to trigger the Bias-Flip switch automatically. And a signal conditioning circuit is designed to measure the vibration frequency. In addition, an experimental setup has been designed and fabricated. It is demonstrated experimentally that the proposed system is able to measure the vibration frequency from 80 to 130 Hz. The measured frequency presents an average relative error of 0.041% after calibration. What’s more, the system is able to harvest enough energy that covers the power consumption of the system over the frequency range of 96–116 Hz under 2-g acceleration with about 74% Bias-Flip efficiency.

A Low-Power CMOS Piezoelectric Transducer Based Energy Harvesting Circuit for Wearable Sensors for Medical Applications

Piezoelectric vibration based energy harvesting systems have been widely utilized and researched as powering modules for various types of sensor systems due to their ease of integration and relatively high energy density compared to RF, thermal, and electrostatic based energy harvesting systems. In this paper, a low-power CMOS full-bridge rectifier is presented as a potential solution for an efficient energy harvesting system for piezoelectric transducers. The energy harvesting circuit consists of two n-channel MOSFETs (NMOS) and two p-channel MOSFETs (PMOS) devices implementing a full-bridge rectifier coupled with a switch control circuit based on a PMOS device driven by a comparator. With a load of 45 kΩ, the output rectifier voltage and the input piezoelectric transducer voltage are 694 mV and 703 mV, respectably, while the VOUT versus VIN conversion ratio is 98.7% with a PCE of 52.2%. The energy harvesting circuit has been designed using 130 nm standard CMOS process.

Novel control system of the high-voltage IGBT-switch

HV solid-state switch control circuit was developed and tested. The switch was made with series connection IGBT-transistors. The distinctive feature of the circuit is an ability to fine-tune the switching time of every transistor. Simultaneous switching provides balancing of the dynamic voltage at all switch elements. A separate control board switches on and off every transistor. On and off signals from the main conductor are sent to the board by current pulses of different polarity. A positive pulse provides the transistor switch-on, while a negative pulse provides their switch-off. The time interval between pulses defines the time when the switch is turned on. The minimum time when the switch is turned on equals to a few microseconds, while the maximum time is not limited. This paper shows the test results of 4 kV switch prototype. The switch was used to produce rectangular pulses of a microsecond range under resistive load. The possibility to generate the damped harmonic oscillations was also tested. On the basis of this approach, positive testing results open up a possibility to design switches under an operating voltage of tens kilovolts.

Research on Railway Signal Distributed Computer Control Switch Module

With the continuous miniaturization, electrical, high-speed and intelligent of railway signal equipment, the control switch module must have higher safety, reliability and anti-interference ability. Under this background, this paper studied the railway signal distributed computer control switch module. First of all, this paper introduced the main supporting technology of distributed interlocking system. These technologies mainly include solid state switch technology, fault tree analysis (FTA) technology, security and reliability design technology and so on. Then, this paper made clear the function requirement of the control switch module according to the characteristics of distributed computer interlocking system and the electrical characteristics of the circuit switch of the machine interface. Moreover, this paper made clear the design method of hardware circuit and software. In the aspect of hardware, this paper mainly analyzed the working principle of the switch control circuit, express acquisition circuit and the communication circuit. In the aspect of software design, this paper focused on the principle and work flow of the micro control unit (MCU) initialization, circuit control and the representation of information detection and so on. Finally, this paper used the fault tree analysis method to carry on the depth analysis of the security of the module. And the analysis results show that the railway signal distributed computer control switch module has a high reliability degree, safety degree and fault - Safety degree. At the same time, the module also meets the system's security index.

Low-Cost Drive Circuit for AC-Direct LED Lamps

This paper proposes a drive circuit for ac-direct LED lamps. The proposed circuit consists only of a line filter, an LED bridge, a load inductor, a bidirectional switch, and a switch-control circuit. The switch connects the LED bridge to the power line directly. Each leg of the LED bridge consists of LEDs and a protection diode, all connected in series. The load inductor limits the bridge current. The switch operates at a zero current switching condition, so the circuit has high power efficiency. The circuit can operate at a free-volt input condition ( $85 ). For all input voltage conditions the circuit had PE > 89%, luminous efficiency ∼90 lm/W, power factor >0.9, and 120-Hz flicker index ∼0.3. The circuit satisfies the IEC 61000-3-2 Class C and the EN 55015 regulations. The proposed LED driver is well suited for use in household LED lamps.

Hard Ware Design of Transformer Terminal Unit (TTU) Based on Substation Automation

The distribution transformer monitoring system is composed of Transformer Terminal Unit (TTU), GPRS wireless communication network and master station. TTU is installed in the transformer, which mainly accomplishes data collection, analysis and record, pops up alarm information in time when the transformer has abnormal events, receives the command from the master station and implements it. GPRS wireless communication network is the bridge of data transmission between the master station and transformers. Master station receives the real-time data of transformers through GPRS wireless communication network, implements further data processing and saving, consequently issues control command. Therefore the system can achieve a comprehensive monitoring and control for distribution transformers. At the same time, it can provide users with a visual interface and let dispatches obtain monitoring performance of far transformers in time for never leaving home. Choosing an appropriate device should also be considered when designing and low power consumption components. From replacement and easy maintenance considerations and reliability, the controller part is independent chassis equipment. We focus on the selection of hard ware component and corresponding hardware design of TTU, designing a high reliability and multifunction TTU which meet the application requirements is an urgent need for substation automation. This paper presents a new hardware design for TTU; the design is composed of seven main parts with its own components which include: conditioning circuit of A-Phase voltage and conditioning circuit of A-Phase current, Circuit diagram of switch input. power supply regulator, Multiplexer switch (AD7506), Clock circuit design output switch control circuit and Communication interface circuit.

A Blumlein-type, nanosecond pulse generator with interchangeable transmission lines for bioelectrical applications

The design and realization of a nanosecond, high-voltage electric pulse generator for bioelectrical applications is reported in this paper. A Blumlein type architecture was adopted, with some modifications, and realized in a microstrip line configuration with meander-shaped conducting strips, and with ultra-fast, high voltage solid state switches. Three microstrip-lines have been realized in such a way that, being interchangeable within the structure, they allow to match different load impedances. A fiber optic-based system was also realized to separate the high voltage side of the system from the switch-control circuit. The system is suitable for applying high voltage nanosecond electric pulses, with variable pulse duration, amplitude, repetition rate and polarity, to liquid media with different electromagnetic characteristics, hosted in electroporation cuvettes with different gap dimensions.