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Induction heating can convert electrical energy to thermal energy with high conversion efficiency and quick heating. Currently, a current source rectifier/inverter-fed parallel resonant circuit is widely used as an induction heating power supply for forging applications. However, the conventional induction heating power supplies composed of phase-controlled rectifier and SCR inverter have low efficiency...
Recently there have been widespread used distributed generators and sensitive loads. It enables solid-state circuit breaker (SSCB) an imperative device to get acceptable power quality of AC power grid systems. The existing AC SSCB composed of SCRs requires some auxiliary mechanical devices to achieve the reclosing operation before fault recovery. But the new AC SSCB can achieve the quick breaking...
The functional architecture of sonar system is presented and its various functions are briefly described in order to describe the matching circuit in its context and to mark the matching circuit. The matching circuit can reduce the energy loss and system size of a sonar system by providing the variable reactive power to Sonar system, and also are influenced by the behavior of this load. In this paper,...
Recently according to the development of DC transmission which is high efficiency, stability of DC grid has become a major concern. Therefore, the reliable DC SSCB (Solid-State Circuit Breaker) is required in order to secure high safety. The previous DC SSCB is unstable and many elements are required in order to perform the operating duty. This paper proposes a new DC SSCB. Since the proposed DC SSCB...
Parametric array transducers are used for long-range and highly directional communication in underwater environment. The power amplifiers for parametric array transducers should have sufficient linear output characteristic and high efficiency to avoid communication errors, system heating, and fuel problems. But the conventional power amplifier with fixed source voltage is very low efficient due to...
Parametric array transducers are used for highly directional speaker in an air environments. Piezoelectric micromachined ultrasonic transducers for parametric array transducers need DC-biased voltage driving signals in order to get high-directional quality-sound features. The existing power amplifier such as class A amplifiers has low efficiency and require large volume heatsinks. To overcome the...
Parametric array transducers are used for highly directional speaker in an air environments. The power amplifiers for them should have sufficient linear output characteristic to amplify high-frequency ultrasonic waves with low THD, and also have high efficiency to avoid system heating and fuel problems. Piezoelectric micromachined ultrasonic transducers for parametric array transducers need DC-biased...
There is no zero crossing of the current in DC power circuits. Thus unless you cut off the short-circuit current quickly, the electrical fire caused by electric arc or spark can occur. And after the initial fault breaking operation the long-duration sustained interruption without fault recovery may cause a lot of serious economic losses. Therefore this paper proposes a new DC SSCB that has quick reclosing...
These days, widespread use of sensitive loads and distributed generators makes solid-state circuit breaker (SSCB) an essential component in power circuits to achieve a high power quality for AC Grids. In the case of previous AC SSCB using SCRs, some auxiliary mechanical devices are required to make the reclosing operation possible before fault recovery. However, the proposed AC SSCB can break quickly...
Parametric array transducers are used for long-range and highly directional communication in an air or underwater environments. The power amplifiers for parametric array transducers should have sufficient linear output characteristic and high efficiency to avoid communication errors, system heating, and fuel problems. But the conventional power amplifier with fixed source voltage is very low efficient...
A new switching scheme for 3-phase interleaved bidirectional DC-DC converter is proposed. The proposed scheme provides soft switching condition for all the switches in both charging and discharging modes regardless of the output power level. Analysis and simulation are carried out for 3kW bidirectional DC-DC converter to charge and discharge a battery of an electric vehicle. Simulation results show...
The paper proposes a new multilevel variable output voltage AC/DC Converter for power supply of power amplifiers used in underwater acoustic sensors. The proposed multilevel variable output voltage AC/DC Converter is composed of two converter sections. One as the input section is a high efficiency phase-shifted PWM full bridge DC-DC converter to get multiport power sources. The other as the output...
The ballast water treatment systems (BWTS) in ships that use electrolytic disinfection needs low-voltage high-current rectifiers with such good performance as high efficiency, galvanic isolation between electric source and electrolysis module unit, light weight and small volume. The proposed rectifier for the BWTS does not only satisfy the above -mentioned features but also has modular output side...
A 3-phase power quality disturbance generator is dealt with for the performance test of high power custom power devices such as DVR, SSTS, dynamic UPS, etc. The major components of the scheme are transformers, power diodes, and natural commutated SCR thyristors, which guarantee high reliability, high efficiency, and low implementation cost. Therefore, the scheme is especially suitable for high power...
This paper deals with the analysis of fault current occurred in a power system including STS, PCS, and load, which are the part of a microgrid. In case of utility side short circuit fault a huge current may flow through a STS, which results in a severe power quality problem in the microgrid. Therefore, minimization of the fault current and STS breaking time is essential to obtain high power quality...
This paper describes a new method for the seamless transfer between voltage and current control modes of a PCS in a microgrid. Usually, microgrid is connected to a utility through STS. In case of short circuit fault a huge current may flow through the STS, therefore, it is necessary to provide a method to reduce the STS fault current. In this paper a novel method to reduce the fault current is proposed,...
This paper deals with a combined system with fuel cell and supercapacitor to provide a power to grid or electrical load. The supercapacitor is used to compensate the slow response of the fuel cell at the instant of abrupt load change. The operation of the bidirectional DC/DC converter for a supercapacitor during charging and discharging is analyzed, and a power control method to maintain a DC link...
In ships the ballast water treatment system (BWTS) of using electrolytic disinfection needs low-voltage high-current rectifiers with such good performance as high efficiency, galvanic isolation between electric source and electrolysis module unit, light weight and small volume. Several rectifier schemes are reviewed as a kind of good rectifier candidate for BWTS and their comparison results are summarized...
A voltage disturbance generator for the test of a microgrid is described. The generator provides the function of voltage sag, unbalance, outage, and phase jump of the output voltage. The proposed generator has good features of high reliability, low cost, simple structure, high efficiency, and easy implementation. The main components of the generator are SCR thyristors and transformers, which provides...
The characteristics of a power quality disturbance generator for microgrid is described. The generator is used to test the performance of a microgrid including STS. The proposed generator has good features of high reliability, low cost, simple structure, high efficiency, and reduced voltage drop. The main switching device is SCR thyristor, and all the thyristors have natural commutation characteristic,...
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