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The recent availability of fast high-power semiconductor switches makes the transformer coupled LC inversion generator (TCLCG) topology a very promising candidate for the realization of reliable, multi-kHz repetition rate pulse generators with an output voltage in the range of 200 kV and more. Usage of 1:1 transformers instead of closing switches in each generator stage reduces the total number of...
Recent development renewable energy increases the requirement in constructing multi-terminal HVDC systems or HVDC grids. To increase the system reliability, an HVDC circuit breaker will be required. However the existing HVDC breakers developed in recent years use large amount of IGBTs. Considering the cost reduction in real HVDC grids, this paper presents a novel hybrid HVDC circuit breaker. The proposed...
The characteristics of pulse thyristors, which are viable for safe switching-on in series connection, are being discussed. The influence of turn-on delay distribution for thyristors in stack generated by overvoltages is being evaluated, including the «convergence» effect of turn-on delay distribution in series connection. There is shown suitability of new thyristor stacks for high current pulses commutation.
In this work, four different snubber solutions for an Auxiliary Resonant Commutated Pole (ARCP) converter with an auxiliary thyristor are evaluated. The first two solutions are an RC snubber and a variation thereoff where the RC snubber losses are reduced by employing diodes for limiting the voltage overshoot. Two other concepts are a novel lossless dV/dt clamp snubber circuit and a low-loss RC snubber...
At present, voltage regulation of no load distribution transformer is not flexible and failure rate of mechanical on-load tap-changers is high. To solve these problems, a scheme of automatic on-load voltage regulation system designed via thyristor for distribution transformer was proposed. The system improved the existing topology of on-load voltage regulation system via power electronic device and...
In this paper, a novel topology of two-level voltage-type inverter is proposed. The proposed inverter has three bridge arms while each bridge is made up of 2 thyristors, 1 IGBT and 4 diodes. Thyristors complete the phase positioning of the inverter, IGBT completes the modulation of different modulation modes such as SPWM, SVPWM, and SHPWM, and the diodes complete the commutation of the bridge arms...
A converter cell for a Modular Multilevel Converter (MMC) suitable for the Chain-Link Converter topology is presented. IGCT semiconductors are being used as the main switch technology thanks to features like • inherent stable Short Circuit Failure Mode (SCFM) capability • very low overall losses • superior load cycling capabilities The cell makes use of a single thyristor switch to protect the cell...
High voltage, pulse power Silicon Carbide (SiC) thyristors have been under development at GE Global Research Center for the past decade. Previous tests of these relatively mature devices have shown that they can reliably hold off high voltages (> 3 kV) at extremely low leakage currents (nanoamps), and carry high pulse currents (> 1.5 kA) on microseconds timescales, while surviving millions of...
In order to realize fine-adjust the current of the pulsed power supply system and reduce the votage of thyristor switch and capacitor demands to maximize the economic benefit. The 9 kJ pulsed power supply units has been built for electromagnetic launching application. The maximum current of the pulsed power unit reachs 30 kA. The PFU is composed of a capacitor, a thyristor, a crowbar diode and a inductor...
Voltage source converter (VSC) such as modular multilevel converter (MMC) has been intensively studied for high voltage direct current (HVDC) applications due to its flexible terminal voltage adjustment, compatibility with weak ac grid and independent active/reactive power control over conventional line-commutated-converter (LCC). However, LCC using thyristors still offers advantages such as high...
The main motivation of this work is to evaluate performance and characteristics of a 6.5kV SiC Thyristor based current switch (series connected active switch and diode). A unique series resonant testing circuit has been proposed to characterize this switch. The device has been tested in several soft and hard turn on and off transitions. Conceptual simulation and hardware results have been presented...
This research is focused on characterization of the turn-on transition of high voltage SiC thyristors of different epilayer thicknesses and active area sizes to determine their suitability and limitations in high-dI/dt, fast-switching applications. The unique aspects of this study include the very high current density being switched through the thyristors over a short period of time at initial turn-on,...
This paper proposes a bypass transfer method without parallel feeding between utility power line and uninterruptible power supply (UPS). This system has ACSWs consists of a bi-directional thyristor and a magnetic contactor both utility power line and UPS line. The control board observes the condition of utility power and UPS to operate ACSWs. A proposed method has instantaneous interruptible period...
This paper presents the comparison between mechanical circuit breaker and solid state circuit breaker under abnormal conditions for low voltage systems. According to the mechanical circuit breaker, the operation was limited on the fault types, detection method and operation error. The solid state circuit breaker is proposed to protect those events using Thyristor as switching device and detection...
In this paper a new class of universal power converters that offers significantly higher reliability and power density will be introduced. Universal power converters are single-stage power converters that are capable of interfacing any types of electrical loads and any types of electrical sources regardless of their form, number of phases or frequency. They are also capable of simultaneously interfacing...
For the future demand of electrical energy, both a reliable and an environmental friendly solution is of high importance. The integration of many widely dispersed regenerative energy sources imposes a great challenge for the existing HVAC grids. A meshed, multiterminal HVDC-SuperGrid is considered to be the best and most efficient solution. This concept would be realized as an overlay grid alongside...
Pulsed power systems which utilize solid state switching devices, rather than spark/gas-type devices, could potentially exhibit increased energy density, repetition rate, operational lifetime, and ruggedness. However, further evaluation of advanced solid state devices, such as thyristor type devices, is required to better understand their operation for pulsed power applications. This paper details...
Thyristor functioning as Arc Eliminator (AE) is presented in this paper, in order to protect low voltage devices such as circuit breakers from damage caused by arc fault. The AE operating mechanism is firstly illustrated, AE is usually working as an active standalone device together with other existing switchgears. The reason of choosing thyristor as AE is mainly because of its fast speed and relatively...
The paper discusses the work carried out on the implementation of control techniques like Digital Pulse Width Modulation, Space vector modulation and Pulse Fired control. These techniques are often used in devices like inverters, battery chargers, DC-to-DC converters can also be implemented on household devices like heaters. The advantage is the control and improved life span of device. In case of...
An auxiliary resonant-commutated pole (ARCP) ensures soft switching in the entire operation range of a three-phase dual-active bridge dc-dc converter. This work evaluates the design and the resulting boost in system efficiency for different semiconductor materials and devices. Afterwards, a full-scale medium-voltage prototype of an ARCP is constructed. The subsequent measurements are presented within...
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