Current Protection Circuit Research Articles

Development of Battery Materials to Function as Corrosion Protection on Car Body Plates

Most car bodies made for mass production are made from steel or aluminum. Both are strong metals, but steel is cheaper than aluminum and is more commonly used in lower-end cars for a broader consumer range. The weakness of steel compared to aluminum is that it is susceptible to corrosion under certain conditions, and thus it may deteriorate over time without proper care. To prevent corrosion, modern cars are coated with paint to prevent direct contact with the environment. As a second line of protection, a car battery can be connected to the body to create an impressed current cathodic protection circuit. In this study, a steel sample from the car body is connected to an ICCP or impressed current cathodic protection circuit with a small 12v battery and a graphite anode. The specimen's paint layers are removed through grinding and tested in water, wet soil, and open air. The specimens in water and wet soil experienced minimum corrosion during the testing period, while the ones in open air experienced significant corrosion products on the surface. Overall, due to the small specimen size compared to battery output, all specimens experience a case of overprotection of up to -5516 mv in wet soil and -2666 mv in water. Due to limitations, we are unable to do proper measurements in the open-air environment.

Control Circuit design of permanent magnet synchronous motor control system based on DSP

This paper introduces the design and implementation of hardware circuit of permanent magnet synchronous motor Servo Controller Based on DSP.In this scheme,TMS320F28335 is used as the control core, and drv8312 is used as the three-phase motor driver chip. The main control circuit, communication circuit, drive circuit, current feedback circuit and protection circuit are designed in detail. The reliability of the control circuit is verified by experiments, and the servo control of PMSM is realized.

Design of high power switched reluctance motor controller

This paper takes the high power Switched Reluctance Motor (SRM) as an example, and designs the control system of the SRM according to the structure and operation characteristics of the high power SRM. The control system takes STM32 MCU as the core, and is composed of driving circuit, current detection circuit and protection circuit. The control methods commonly used in SRM include current chopper control (CCC), voltage chopper control (VCC) and Angle position control (APC). In addition, PI closed-loop control strategy is used to optimize the system performance, which verifies the feasibility and stability of the design of the motor control system.

Design and implementation of multiple output forward converter with Mag-amp and LDO as post regulators for space application

Linear power supplies are commonly used power supplies for many applications. They have some drawbacks such as low efficiency, difficulty in thermal management and also in regulation of the output voltage. Some of these drawbacks can be overcome by Switch Mode Power Supplies (SMPS). One of the best-suited applications of SMPS is for space applications that require power supplies which are lighter, smaller, more efficient and highly reliable. Multiple-output DC-DC converters are an important topology of SMPS that can be used for space applications. But, in multiple output converters usually, only the master output is regulated and the other outputs are left unregulated and this can result in cross-regulation. In this paper, post regulators such as Magnetic amplifiers (Mag-amp) and Low DropOut regulator (LDO) are proposed to regulate each output and also to improve load regulation. In addition to this, the input voltage feed-forward control technique is proposed to control the duty cycle of the switch, which is dynamically faster and provides better line regulation when compared to the voltage feedback controller. Besides, over current protection circuit for the converter is discussed in detail.
 Keywords: Cross regulation effect, Mag-amp and LDO, multiple output forward converter, output over current protection, voltage feed forward control.

A further analysis of blocking action of the circuit breaker in the relay protection

With the development of the ages and social progress, our country has enormously developed in the field of smart power system. In most of the power systems, the hydraulic actuator, the operating mechanism and the spring energy storage operating mechanism are all the core issues in the current relay protection circuit breaker opening and closing. The effect of its operation will have a direct impact on the power system and circuit breaker performance. In this paper, by classifying the circuit breaker operating and analyzing the relationship between the blocking action and the relay protection, we can further analyze the blocking action of the circuit breaker in the relay protection, so that we can choose the better action position, and analyze and make researches by following the circuit wiring and dual configuration.

Overcurrent protection utilising high speed and accurate current sensing circuit for switching mode DC-DC converter

ABSTRACTA high speed and accurate over current protection (OCP) circuit with novel current sensing circuit based on source-degeneration voltage to current converter is presented in this paper for switching mode DC-DC converters. Moreover, a reference generator circuit is designed to generate current set point to be compared with sensed current for OCP. Another four bit binary decoder is employed to control and change the current set point to achieve different levels for OCP. To reduce the fluctuations at the output of the OCP, a blanking-delay block is introduced based on Schmitt trigger topology. The OCP is designed with 130 nm CMOS process technology. Post-layout simulation results show that the OCP works well from 0.5 V to 5 V output voltage of switching mode DC-DC converter. The current sensing block achieves wide input common mode range between 0.5 V and 2.5 V with 61 degree phase margin. OCP works with 3.3 V supply voltage while consuming 600 µA at standby mode and 2 mA when triggering. Total silicon die area is 242 µm × 186 µm.

Design of high frequency modulation system of semiconductor laser based on PSpice

In order to output high frequency modulation, we designed a high frequency modulation system of semiconductor laser which is composed of a signal magnifying circuit, a current modulation circuit, an over current protection circuit and a DC bias circuit with slow start function. The high frequency modulation drive system of semiconductor laser uses a simple structure of the direct modulation method. The direct modulation method controls intensity of semiconductor laser by a signal of adjustable frequency. We simulated the high frequency modulation drive system of semiconductor laser by OrCAD/Pspice. The high frequency modulation system of the semiconductor laser can output laser with frequency of 40.02 MHz and average laser power of 300 mW, and it can output modulation current with DC bias of 493.326 mA and peak value of sine wave modulation of 850 mA.

Design of Constant Current Electronic Load Base on STM32

In order to improve the utilization efficiency of the electrical laboratory and reduce the experimental cost, the paper designs the adjustable constant current electronic load. The single-chip digital port reads the current reference value and sample load current controller with reference value of 12 bit DAC chip; using general operational amplifier to realize PID regulator, to realize constant current and overvoltage protection circuit using selective control simulation. The electronic load can realize the constant current load mode, and has the functions of over voltage protection, keyboard input, digital display, complete function and low cost. The DC current stability of the prototype is close to 99%, and the stability of the AC constant current is 99.8%.

High-Temperature SiC CMOS Comparator and op-amp for Protection Circuits in Voltage Regulators and Switch-Mode Converters

This paper describes a high temperature voltage comparator and an operational amplifier (op-amp) in a 1.2- $\mu \text{m}$ silicon carbide (SiC) CMOS process. These circuits are used as building blocks for designing a high-temperature SiC low-side over current protection circuit. The over current protection circuit is used in the protection circuitry of a SiC FET gate driver in power converter applications. The op-amp and the comparator have been tested at 400 °C and 550 °C temperature, respectively. The op-amp has an input common-mode range of 0–11.2 V, a dc gain of 60 dB, a unity gain bandwidth of 2.3 MHz, and a phase margin of 48° at 400 °C. The comparator has a rise time and a fall time of 38 and 24 ns, respectively, at 550 °C. The over current protection circuit, implemented with these analog building blocks, is designed to sense a voltage across a sense resistor up to 0.5 V.

Hybrid Control Strategy for Matrix Converter Fed Wind Energy Conversion System

In this paper, a hybrid control strategy for a matrix converter fed wind energy conversion system is presented. Since the wind speed may vary, output parameters like power, frequency and voltage may fluctuate. Hence it is necessary to design a system that regulates output parameters, such as voltage and frequency, and thereby provides a constant voltage and frequency output from the wind energy conversion system. Matrix converter is used in the proposed solution as the main power conditioner as a more efficient alternative when compared to traditional back-back converter structure. To control the output voltage, a vector modulation based refined control structure is used. A power tracker is included to maximize the mechanical output power of the turbine. Over current protection and clamp circuit input protection have been introduced to protect the system from over current. It reduces the spikes generated at the output of the converter. The designed system is capable of supplying an output voltage of constant frequency and amplitude within the expected ranges of input during the operation. The matrix converter control using direct modulation method, modified Venturini modulation method and vector modulation method was simulated, the results were compared and it was inferred that vector modulation method was superior to the other two methods. With the proposed technique, voltage transfer ratio and harmonic profile have been improved compared to the other two modulation techniques. The behaviour of the system is corroborated by MATLAB Simulink, and hardware is realized using an FPGA controller. Experimental results are found to be matching with the simulation results.

Robust Design of a Solid-State Pulsed Power Modulator Based on Modular Stacking Structure

This paper describes the design of a robust high-voltage solid-state pulsed power modulator (SSPPM), which requires reliable series stacking and driving of a number of semiconductor switches. For voltage balancing against overvoltage during both at transient and at steady-state, the power-cell-based modular stacking structure consists of an energy storage capacitor, bypass diode, and switching device (such as an insulated-gate bipolar transistor or a metal-oxide-semiconductor field-effect transistor (mosfet)). In addition to the reliable voltage balancing of each switching device, the modular power cell stacking structure provides a fault-tolerant design by allowing individual protection circuit for each switching device. In this paper, the inclusion of a compensating third winding is proposed. This compensating third winding solves the voltage unbalance issue, which results from difference of leakage inductance of separate located transformer core, using magnetic flux compensation. A protection method using this compensating winding is also suggested to detect abnormal occurrences in each power cell under operating conditions. Additionally, an arc current protection circuit to ensure continuous operation of the SSPPM is designed. Through simulation and experimental results of tests on the SSPPM with the structure outlined earlier, it is verified that the proposed design can be used effectively, as it exhibits both robustness and reliability.

Fast transient response high‐accuracy current‐sensing technique for step‐up DC–DC converter

A novel current-sensing technique with fast transient and high accuracy for a step-up DC–DC converter is presented. This circuitry is applied for sensing the current flowing through the equivalent series resistor (ESR) of the inductor to obtain the inductor current information. It is achieved with a fast transient response circuit (FTRC), an operational amplifier, a current-sensing stage and an overshoot current protection circuit. The process offsets of the transistors, which can increase the current-sensing accuracy, and provide an additional current feedback loop to decrease the transient response time are compensated by the FTRC. When the sensed current is higher than the maximum value, the overcurrent protection (OCP) will be operating to let it shut down. This current-sensing technique has been integrated in a step-up DC–DC converter with standard 0.35 μm CMOS process. Experimental results show that the accuracy is higher than 98% and the transient response recovery time is ∼100 μs with load current changing from 3 A to 10 mA.

Research and Improvement of Leakage Protection System in Coal Winning Machine

Most of the Shearer adopt additional DC power protection, it has to protect a comprehensive, capacitive current compensation, the simple characteristics of action value of the tuning, however, it in the actual production will occur leakage protection device malfunction, tripping phenomenon For the leakage protection circuit in traction motor of coal winning machine is impacted by frequency converter devices in the course of their work, malfunctions appear frequently. This paper makes an in-depth analysis, analyzing the shortcomings of the current protection circuit, After the analysis of the interference signal, it is proposes a solution of using the subtraction circuit to offset interference signals and conducts a simulation analysis. The above scheme, which is simple and easily realized, can improve the reliability of leakage protection device in traction motor. Avoiding unnecessary production halts. The production efficiency can be improved.

A Low-Power High Accuracy Over Current Protection Circuit for Low Dropout Regulator

In this paper, a low power current protection circuit implemented in a low dropout regulator (LDO) is presented. The proposed circuit, designed in a 0.35 μm CMOS process, provides a precise limiting current as well as holding current with low dependency on both supply voltage and regulator output voltage. The experimental results showed that the proposed circuit is operable in the regulator output voltage range from VOUT=1.2V to VOUT=3.6V and supply voltage range from VDD=VOUT+0.5 V to VDD=5.6 V. Since the proposed circuit is composed of few simple basic circuits such as a comparator and a Schmitt Trigger, it has a low current consumption of less than IS S=0.82 μA at a load current of ILOAD=200 mA. This makes the circuit suitable for low power and low voltage LDO design.

Overcharge current protection circuit and battery pack using same

A battery pack (62) comprises cells (74), and is charged by a charger (64) providing a current level. The charger (64) is a typical nickel-cadmium battery charger providing a first charge current level in excess of an optimum charge current level. The battery pack (62) further comprises a thermal sensing element (76) and an overcurrent charge protection circuit having an overcurrent switch (78), current sense circuit (80), comparator circuit (82), and temperature signal switch (84). If the current level through the cells (74) exceeds the optimum charge current level, the current sense circuit (80) provides a signal to comparator circuit (82) which actuates the temperature signal switch (84), simulating a hot battery pack. The charger (64) then switches to a second charge current level which does not exceed the optimum charge current level. If the charger (64) does not change current levels, a switch delay (86), after a brief period, accumulates enough voltage to actuate a driver switch (88) which opens the overcurrent switch (78), disconnecting the cells (74) from the charger (64).