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This paper discusses a AC-DC converter which is constructed by a Modular Multilevel Converter (MMC) for a wind power generation system connected to Micro-grid. The proposed system which is constructed the MMC with an H-bridge cell achieves to convert from a generator voltage of 3.3 kV into DC bus voltage of 340 V. Moreover, as a fundamental evaluation, the experimental result by miniature model of...
DC capacitors are widely adopted in grid-connected PhotoVoltaic(PV) systems for power stabilization and control decoupling. They have become one of the critical components in grid-connected PV inverters in terms of cost, reliability and volume. The electrical and thermal stresses of the DC capacitors are varying along with the intermittent solar PV energy (i.e. of weather-dependency) and also the...
This paper describes the PLC based control system developed for a 40kJ/25kV Electro-magnetic machining (EMM) system. In EMM system large capacitor banks is charged with high voltage to store large energy and the banks is made to discharge into a coil within few milli-seconds using a triggered spark gaps. During discharge of the capacitor large surges and transients are generated in the system. The...
In this paper, optimal DC-link voltage balancing control for 3-level half-bridge series resonant DC-DC converter is proposed. The proposed converter can minimize switching frequency variation according to load and improve overall efficiency for a wide range of loads. However, the performance of proposed converter can be lowered by DC-link voltage unbalance. For figuring out voltage unbalance problem,...
A single-stage power converter for dc uninterruptible power supply (UPS) is proposed in this paper. Basically the proposed converter is an integration result of a power factor correction circuit with a dc-to-dc converter to achieve simple hardware circuit, high efficiency, and low cost for extra UPS function. Under normal operation, a two-switch CUK converter operates as an ac to dc converter with...
Excellent dynamic behavior and controllability even under fault conditions are main requirements of future electric drive systems. The Modular High Frequency Converter (MHF) fulfills these requirements and enables additional advantages especially low weight, low volume and redundant operation after faults. This paper presents control strategies and stability considerations for the new topology of...
This paper presents the mitigation of faults in wind turbine connected fixed speed induction generator using dynamic voltage restorer (DVR) and Static Synchronous series compensator (SSSC) because of its excellent performance of fault mitigation. The DVR consists of shunt and series converters connected back-to-back through a dc-to-dc step up converter. The presence of the dc-to-dc step converter...
A Distribution Static Synchronous Compensator (DSTATCOM) is introducing here to compensate the voltage sag problem by injecting proper reactive current at the point of common coupling. In this paper, the performances and effectiveness of DSTATCOM to nullify the voltage sag are analyzed and a control algorithm based on PI and Hysteresis PWM current controller is developed to verify the results. A 6...
Hysteretic control is widely adopted in the power management units (PMUs) for modern electronic devices due to their simple and stable control architecture, as well as the fast load transient response. However, the switching frequency of a traditional hysteretic converter is not fixed. It changes with operating condition and component aging, and hence brings in electro-magnetic interference (EMI)...
Solar photovoltaic energy systems have received increasing attention during the last years due mainly to the cost reduction of solar panels and the availability of power converters specifically designed for these applications. Small scale photovoltaic plants have been installed to fed houses and small business whether connected to the grid or stand-alone. In the latter case, the converter must provide...
This work shows how an electrostatic energy harvester based on a “doubler of electricity” can be used as energy source for low-power applications, without the need of a battery, and describes a suitable control system for it. The fact that the generator can be made to start from very small initial charge, which can be provided by electrical noise or external interference, is used to eliminate the...
This paper presents the vector control design of an axial-flux permanent magnet motor (AFPM) driven by a current source inverter (CSI), which is considered as having many advantages over the voltage source inverter. The control system consists of a 2-DOF speed controller, a multi-loop current controller, and an SVPWM modulation block, which can offer a faster dynamic response, an instantaneous adjustment...
DC power systems comprising single-phase DC/AC inverters draw low-frequency AC ripple currents at twice the output frequency from the DC input. Such a 100/120 Hz ripple current may create instability in the DC clean energy system, lowers its efficiency, and shortens the lifetime of the DC source. This paper presents a general waveform control method that can mitigate such a low-frequency ripple current...
This paper presents a linear constant current LED driver with no off-chip inductor or capacitor. The proposed circuit consists of a main controller and constant current sources to drive the LED array. An improved control method is used for lighting the LED array step by step, shaping the output current in proportion to the input voltage. Each constant current source has functions of temperature compensation...
The search for new energy sources has lead to the installation of renewable energy plants located far away from the centers of consumption. In this scenario, the transmission of electrical energy over long distances has become a key issue and high voltage DC (HVDC) transmission systems have demonstrated to be the best cost effective solution. Among the different HVDC technologies, modular multilevel...
Voltage differential feedback control system based on repetitive control is proposed in this paper. The scheme, which can improve the dynamic characteristic and steady state performance by Capacitor voltage as outer loop while its differential as inner loop without current sensor, is achieved on a three-phase PV inverter with TMS320F2808. Two different control strategies, traditional and repetitive...
This paper describes the design and construction of an improved PID controller for a DC-DC buck converter working in Continuous Conduction Mode (CCM). The converter operates at a switching frequency of 1MHz. The lead-lag controller is first designed on the basis of classical theory of control systems using root-locus technique. The controller is then equivalently converted into a PID controller. The...
This paper aims to present a comparative analysis of a computationally implemented model of an Unified Power Flow Controller (UPFC) and an ASC (Advanced Series Compensator) through case studies. To do so, a description its principle of operation and mathematical modeling, comprehending the series and parallel compensators, is given so that the control objectives can be determined using the vector...
In this paper, a nonlinear control algorithm for a current-fed DC-DC is presented. This converter consists of an inductor, a controllable full-bridge converter, which is connected to a full-bridge rectifier via a high-frequency transformer. The advantages of this converter include galvanic isolation, high voltage gain and low input current ripple. Based on Flatness properties, we proposed a controller,...
The fundamental building block of cascaded static synchronous compensator used in distribution grid is H-bridge based converter module. In this paper a type of "plug and play" module was introduced to improve the device compensation performance and reliability. The module based on IGBT parallel connection was discussed about the design of electrical parameters and physical structure. In...
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