Short-circuit Protection Research Articles

Fuse-Based Short-Circuit Protection of Converter Controlled Low-Voltage DC Grids

Low-voltage dc (LVdc) microgrids emerge as a viable alternative to ac microgrids. A large research interest is noted toward fast and selective protection of dc grids, typically focusing on hybrid or full solid-state solutions. In this article, the use of fuses as short-circuit protection in low-voltage dc microgrids is evaluated. The main advantage of fuses is that they are simple, cheap, standardized, and have low steady-state losses. A theoretical basis is formed to model dc short-circuit currents in grids with a limited short-circuit availability. The outcomes are applied to evaluate the possibilities of fuse protection in LVdc grids. It was found that fuses are an effective means of protection, although the required amount of capacitance at the output of the voltage balancing converter can be high, which impacts the total system cost. A fuse-based protection strategy is presented that highlights the need for additional capacitance to clear faults compared to the necessary capacitance for system stability. An experimental setup was built to validate the claims.

A self-adaptive blanking time circuit for fast IGBT de-saturation short-circuit protection

A self-adaptive blanking time circuit for fast IGBT de-saturation short-circuit protection

Electrical and thermal interplay in lithium‐ion battery internal short circuit and safety protection

Electrical and thermal interplay in lithium‐ion battery internal short circuit and safety protection

Construction of High Precision AC-DC Power Supply

Several accessible power supply equipment with different difficulty levels and complexity mostly give a singular DC output that does not provide same use when an Output AC Power that is quite low to a great extent preferred. In this work, a stabilize, fixed and varying power supply device that has output voltage of 0.5 V to 18.15 V variable DC, and current range from 0 - 0.88 A with short circuit protection was constructed by using inexpensive materials, and fuse was used as circuit breaker . Likewise, we examined the regulation attributes of the power supply units that is just been constructed to a specific load regulation to decide its strength by contrasting it with a regular power supply device and ascertain the power supply's effectiveness through its efficiency. Test and examination were carried out utilizing the developed power supply unit to power loads of 10 to 50 Ω. The trend of the output results demonstrated that the power supply was in line with the standard PSU. The output supplied would be useful in research facility estimation to supply the power for direct incorporated circuits, delicate circuits, simple and advanced circuits, TTL and wide-ranging applications necessitating supply force.

Implementation and Experimental Verification of Smart Junction Box for Low-Voltage Automotive Electronics in Electric Vehicles

In this study, we designed and implemented a smart junction box (SJB) that was optimized for supplying power to low-voltage headlights (13.5 V) in electric vehicles. The design incorporated a number of automotive semiconductor devices, and components were placed in a high-density arrangement to reduce the overall size of the final design. The heat generated by the SJB was efficiently managed to mount an Intelligent Power Switch (IPS), which was used to power the headlights onto the printed circuit board (PCB) to minimize the impact on other components. The SJB was designed to provide power to the headlights via pulse width modulation to extend their lifetime. In addition, overload protection and fail/safe functions were implemented in the software to improve the stability of the system, and a controller area network (CAN) bus was provided for communications with various components in the SJB as well as with external controllers. The performance of the SJB was validated via a load operation test to assess the short circuit and overload protection functions, and the output duty cycle was evaluated across a range of input voltages to ensure proper operation. Based on our results, the power supplied to the headlights was found to be uniform and stable.

Tunnel Magnetoresistance-Based Short-Circuit and Over-Current Protection for IGBT Module

This article presents a short-circuit and over current protection method using a new current sensor-tunnel magnetoresistance (TMR). The resistance of TMR changes with the magnetic flux density and a Wheatstone bridge circuit-based TMR can be used for current measurement. A toroid TMR current sensor is first proposed to measure the IGBT current, and the measured current is compared to references for protection. A prototype based on a 1200-V/200-A IGBT module is constructed to test the TMR sensor. A 120 A over-current can be detected in 604 ns. The measured current is also utilized to estimate the dc bus capacitance, experimental results show the maximum estimation error is 0.26%. Next, the TMR sensors are integrated into an IGBT module to expand the application scenario. The Calculation method and finite element method (FEM) are proposed to find optimal install locations of the TMR inside a 62-mm IGBT module. A differential TMR sensor circuit is employed to suppress the interference of the adjacent magnetic field. Experimental results based on a commercial IGBT with an integrated TMR sensor have been provided. The reaction time of the integrated TMR sensor is 530 ns and the maximum measurement error for the dc current is 0.85%. The detection and protection time for a 280-A short-circuit fault is 677 ns and 1.23 μs, respectively.

A Reliable Ultrafast Short-Circuit Protection Method for E-Mode GaN HEMT

A unique three-step short-circuit protection method is proposed for the 650-V enhancement mode (E-mode) gallium nitride high-electron mobility transistor (GaN HEMT). This method can quickly detect the short-circuit event, reduce gate voltage to enhance the device short-circuit capability, and turn off the device under fault after confirmation. Experimental results prove that with this method, the short-circuit fault detection time for E-mode GaN HEMT is shortened from 2 μ s to several tens of nanoseconds, and the device can be successfully protected from fatal failure under high dc bus voltage without mistriggering.

A Novel IC Measurement Without Blanking Time for Short-Circuit Protection of High-Power IPM

Intelligent power module (IPM) short-circuit protection is a key factor in improving the reliability of power electronics systems. The conventional short-circuit detection method based on monitoring the collector-emitter voltage (VCE) desaturation has a blanking time and is slow to respond to any type of shortcircuits. Furthermore, the diC/dt method cannot be used in the IPM due to the absence of Kelvin emitter. A slow short-circuit protection process can have an irrecoverable and destructive impact on the reliability of the IPM. In this paper, a new high-power IPM topology with an internally integrated shunt is designed to realize real-time current detection, which can achieve fast short-circuit detection without any blanking time. A prototype 1700 V/150 A IPM is manufactured, and a corresponding fast short-circuit protection circuit is designed. Experimental results show the effectiveness of the integrated shunt method as its performance is significantly better than that of the VCE desaturation method. The proposed IPM needs 380 ns and 1.4 μs to detect short-circuits of types I and II, respectively. The short-circuit withstand times for short-circuits of types I and II are 2.06 μs and 0.62 μs, respectively. In addition, the short-circuit energy losses for shortcircuits of types I and II are reduced by 66% and 64.3%, respectively, compared to the VCE desaturation method. The proposed method can also be used as a reference for other IPM designs.

Design and Simulation of Cyclic Battery Tester

Abstract The paper presents an approach to the modelling of a cyclic battery tester and contains observations about lithium-ion (Li-ion) batteries, charging/discharging procedures, conditions and protections which must be observed during the testing process. The main goal was to create and simulate a schematic which will be capable of cyclically testing Li-ion battery cells. Regulation of the final schematic is based on cascade connections of operation amplifiers, which work as a voltage source with current-limiting functions. The power part is created by two MOSFETs connected as a half-bridge. This topology allows current to flow in both directions (from and to the battery). Final simulation is supplemented by protections such as reverse polarity protection, short circuit protection and overvoltage protection during charging. Proper operation of the whole connection is demonstrated by the simulation outputs in the final section.

High-Speed Permanent-Magnet Generator with Controlled Magnetic Flux for Aerospace Application

This paper presents the design of a 150-kVA 24,000-rpm high-speed permanent-magnet generator with controlled magnetic flux for an auxiliary power unit in more electric aircrafts. Electromagnetic, mechanical, thermal, and hydraulic calculations have been carried out. The generator is designed in order to operate without high-performance inverters in the framework of aviation standards. The additional toroidal winding, fed by a simple regulator with a direct current, is implemented in order to perform a variety of additional functions such as short-circuit protection, providing a starter launch by using the increased voltage of the main aircraft engine’s starter-generators, and adjusting the voltage of the auxiliary power unit in a given range. Based on the multi-physics design calculations, a full-size experimental SG prototype with an additional winding located on the stator back has been manufactured and tested. The experimental results are in good agreement with the computer simulation data, demonstrating the proposed technology and the additional functionalities within a power-to-mass ratio of 4 kW/kg.

A Hybrid Topological Design of Led Driver for Automotive Applications

Light-emitting diodes (LEDs) have long been utilized as the default component for signaling and interior lighting applications in automotive industry. The response rate of an LED as compared to a traditional incandescent bulb is ten times faster. The ease of maintenance and controllability feature of LEDs also makes them a natural choice for intelligent lighting system. This lighting can be adjusted based on the sensor inputs of a vehicle with ease. The multi lighting capabilities of a LED driver provides options that can address multiple applications with the same LEDs. A constant current is required for uniform LED lighting. Owing to the high reliability on LEDs for an array of applications in the automotive sector, additional circuitry for over voltage protection, under voltage protection, reverse polarity risk, over current protection, over temperature protection and short circuit protection needs to incorporated. The proposed design provides a improvement of 5% over the state of the art existing topology for over voltage protection.

Comparative Design of Gate Drivers with Short-Circuit Protection Scheme for SiC MOSFET and Si IGBT

Short-circuit faults are the most critical failure mechanism in power converters. Among the various short-circuit protection schemes, desaturation protection is the most mature and widely used solution. Due to the lack of gate driver integrated circuit (IC) with desaturation protection for the silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET), the conventional insulated gate bipolar transistor (IGBT) driver IC is normally used as these two devices have similar gate structure and driving mechanism. In this work, a gate driver with desaturation protection is designed for the 1.2-kV/30-A SiC MOSFET and silicon (Si) IGBT with the off-the-shelf driver IC. To further limit voltage-overshoot at the rapid turn-off transient, the active clamping circuit is introduced. Based on the experiments of switching characterization and short-circuit test, the SiC MOSFET shows faster switching speed, more serious electromagnetic interference (EMI) issue, lower switching loss (half), and higher short-circuit current (1.6 times) than the Si IGBT, even with a slower gate driver. Thus, a rapid response speed is required for the desaturation protection circuit of SiC MOSFET. Due to the long delay time of the existing desaturation protection scheme, it is technically difficult to design a sub- μ s protection circuit. In this work, an external current source is proposed to charge the blanking capacitor. A short-circuit time of 0.91 μ s is achieved with a reliable protection. Additionally, the peak current is reduced by 22%.

Control and Protection in Low Voltage DC Grids

Many office applications are low power such as computers, monitors, laptops, phones and even LED lighting. Powering them from a 48 volt DC grid is sufficient and has one great advantage. Namely, the 48volt is safe regarding touching. However, protection to prevent excessive short circuit currents has to be provided. In this paper we discuss a 48 volt DC grid that is implemented as a living lab. In the living lab, droop control and short circuit protection are implemented. The 48 volt DC grid is connected to a 350-400 volt DC grid via a bidirectional DCDC converter. The 350-400 volt DC grid is used for powering higher power levels such as air conditioning, battery storage, photovoltaic or an AC grid-tied inverter for power exchange. The theory behind and implementation of droop control, via a hybrid analog/digital controller is discussed along with measurements. Predictive short-circuit protection is discussed to prevent excessive short circuit currents. Earth leakage detection via monitoring is discussed as well as its advantage for DC grids. Droop control and protection are combined in a Grid Manager that regulates each load individually.

The Two-Dimensional Short-Circuit Detection Protection For SiC MOSFETs in Urban Rail Transit Application

This article is an extension of our research, which was presented at the PCIM Europe conference in Nuremberg 2019. After proving the potential of the two-dimensional (2-D) short circuit detection method for SiC mosfet s in the preceding work Hofstetter et al. , this article presents the use of the protection system in an urban rail transit application. This introduces many challenges. It is shown how to calibrate the detection system when facing the challenge of different Miller plateaus due to temperature and dc-link voltage ranges and charge carrier trapping effects. Additionally, the effects due to parallelization are examined. False detections due to drain current oscillation are prevented with a simple additional circuit, which is used to suppress the oscillation from the detection circuit. This method leads to a minor increase in current until detection in a short circuit type 2 event. All the techniques and circuitry are experimentally verified and validate the 2-D short-circuit protection as a perfect candidate for the use in urban rail transit application.

Overload and Short-Circuit Protection Strategy for Voltage Source Inverter-Based UPS

In this paper, an overload and short-circuit protection method is proposed for voltage source inverter-based uninterruptible power supply (UPS) system. In order to achieve high reliability and availability of the UPS, short circuit and overload protection scheme are necessary. When overload or short circuit happens, using the proposed control method, the amplitude of the output current can be limited to a constant value, which can be set by the customer to avoid the destruction of the power converter, and to obtain a faster recovery performance as well. The detailed principle of the proposed protection method is discussed in this paper. It mainly contains three parts in the control diagram for current limit, first is the anti-windup in the voltage and current controllers, then the feedforward of the capacitor voltage to the current control loop, the last is the fast reset of the resonant part of the current controller when overcurrent happens. The procedure of developing the control method is also presented in the paper. Experimental results on a commercial UPS system are presented to verify the effectiveness of the control method.

Analysis of high-voltage DC fuse’s ageing characteristics under the overload pulse current carrying mode and the caused short-circuit failure in series-resonant converter power source

As a key component in short-circuit protection, high-voltage fast DC fuse is broadly employed in high-power charge sources. In this paper, the overload pulse current carrying and ageing effect of high-voltage fast DC fuse which is used in series-resonant converter power source for short-circuit protection, is studied and analyzed. Main focus is on the mechanism of the DC1600V/32A fuse ageing and the following cut-out effect under the condition of high-frequency overload pulse current carrying. The effects on the full-bridge series-resonant converter charge source after the fuse ageing and breaking are also analyzed. The ageing under pulse currents is mainly caused by the repeated attacks of the heating-up and cooling on the fuse conductor. Four encountered stages of the fuse conductor under the high-frequency overload pulse current carrying are put forward in order, such as the linear ageing stage, the non-linear ageing stage, the fusing and arcing stage, and the arc extinguishing stage. In the linear ageing stage which plays as the available fuse life time, the fuse conductor carries the pulse currents normally and the temperature rise and fuse resistance Rf both increase linearly. When the increment ratio of Rf reaches 10%, the fuse starts to work in the non-linear ageing stage in which Rf increases nonlinearly and the series-resonant period of the charge circuit is prolonged. As the alternately opening switches in the H-bridge of the series-resonant converter are mismatched, the H-bridge is in short-circuit error, or the phenomena of the ‘hard switching’ and the failure for series-resonance occur. The circuit simulation and experimental results both demonstrate the H-bridge short-circuit error in series-resonant converter charge source is induced by the ageing of the fuse conductor under the overload pulse current carrying condition. In view of that, several ways for improving the fuse conductor ageing are put forward.

Development of fast short-circuit protection system for advanced IGBT

The higher current density of IGBTs has made it difficult to achieve high short-circuit withstand capability as well as good conduction characteristics. Therefore, a fast and reliable protection system is required for the safe operation of IGBT. This paper determines the short-circuit safe protection area (SCSPA) for advanced IGBT that has no short-circuit withstand capability and proposes the protection system satisfied this SCSPA. The fast protection is brought by PCB Rogowski coil and digital gate driver using digital circuit (FPGA). Experimental results verify that short-circuit detection time is 70 ns, shut-down time is reduced by controlling the gate resistance at turn-off.

A SiC JFET-Based Solid State Circuit Breaker With Digitally Controlled Current-Time Profiles

DC distribution networks are able to effectively improve the energy efficiency and easy integration of distributed generations. However, the reliable dc circuit breaker is an essential requisite for the wide application of dc power. This paper proposes a self-powered solid-state circuit breaker (SSCB) with a digitally controlled current–time profile for both ultrafast short-circuit protection and overcurrent protection. The fault detection unit detects short-circuit or overcurrent conditions by sensing the sampling resistance voltage and delivers these voltage signals to a low-cost microprocessor to realize the protection operation of the SSCB. A pulsewidth modulation (PWM) current limiting protection method with time interval $T_{d}$ is proposed to avoid nuisance tripping caused by inrush current during power electronic load startup. The time interval is properly selected based on the transient thermal properties of silicon carbide (SiC) junction gate field-effect transistors (JFETs). In order to verify the dynamic response of the SSCB, a SiC JFET-based circuit breaker prototype is designed and fabricated for result confirmation.

Two-dimensional temperature distribution of air arc commutating to arc runner

Molded case circuit breakers (MCCBs) are used to provide overcurrent and short-circuit protection for low-voltage devices with rated currents of several hundreds of amperes. In MCCBs, some arc discharges have been observed to remain on the contacts and hardly move to the arc runners. Information about the temperature distribution over an air arc plasma is indispensable in investigating and clarifying such arc-commutation phenomena. We propose a new optical system that enables dynamic measurement of the two-dimensional temperature distribution over air arc via the two-line radiance ratio method. The system consists of a four hold-lens array, a high-speed video camera, and interference filters whose wavelengths correspond to the emission spectra of air arcs with metallic vapor. The dynamics of the air arcs in a mock MCCB was measured with this system. The anode root commutates to the runner, where its ambient temperature exceeds threshold Tth, by contrast, there was no clear threshold temperature for cathode-root commutation. The Tth was 8000 K and 6000–7000 K for Cu runners and Fe runners, respectively. Light emitting spheres, which were presumably molten droplets, were emitted from the anode root and often triggered the commutation of the cathode root.

A Digital-Controlled SiC-Based Solid State Circuit Breaker with Soft Switch-Off Method for DC Power System

Due to the lower on-state resistance, direct current (DC) solid state circuit breakers (SSCBs) based on silicon-carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) can reduce on-state losses and the investment of the cooling system when compared to breakers based on silicon (Si) MOSFETs. However, SiC MOSFETs, with smaller die area and higher current density, lead to weaker short-circuit ability, shorter short-circuit withstand time and higher protection requirements. To improve the reliability and short-circuit capability of SiC-based DC solid state circuit breakers, the short-circuit fault mechanisms of Si MOSFETs and SiC MOSFETs are revealed. Combined with the desaturation detection (DESAT), a “soft turn-off” short-circuit protection method based on source parasitic inductor is proposed. When the DESAT protection is activated, the “soft turn-off” method can protect the MOSFET against short-circuit and overcurrent. The proposed SSCB, combined with the flexibility of the DSP, has the μs-scale ultrafast response time to overcurrent detection. Finally, the effectiveness of the proposed method is validated by the experimental platform. The method can reduce the voltage stress of the power device, and it can also suppress the short-circuit current.