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A voltage controller for the operation of three-phase single switch boost rectifier is proposed using low cost op-amps. The controller automatically adjusts the pulse width of the boost rectifier to maintain a constant dc load voltage of desired level, despite the variations in the load and source voltage. Methods have been proposed for calculating the duty ratio to obtain the desired dc load voltage...
The auxiliary converter (AXC) has been presented as a cost-effective solution to retrofit the conventional diode rectifier into a unity power factor and regeneration-enabled front end. The transistor-based AXC operates as an active filter when the load system consumes power. When the load system regenerates, the AXC can transfer the energy back to the ac grid. However, the pulse width modulation (PWM)...
In this paper, the Line-Modulated Fixed Off-Time method is used as the current control strategy for a Power Factor Corrector (PFC) pre-regulator. A zero voltage switching PWM (ZVS-PWM) auxiliary circuit is configured to perform ZVS in the switches. Soft commutation of the main switch is achieved without additional current stress. A significant reduction in the total conduction loss is achieved, since...
Supplying power for DC energy storage unit of power quality compensator by rectifier will produce much harmonic and decrease power factor. Active power factor correction technology can resolve the problem, but it will bring much switching loss and put forward higher requirements to the frequency and stress of power device. It proposed soft switching power transformation technology to control switching...
This paper focuses on a three-level pulse width modulation (PWM) rectifier with direct power control (DPC) strategy based on switching table. The influences of power control coupling on system performances are analyzed and an optimized three-level DPC strategy is developed. The proposed three-level DPC changes the selection of control vectors dynamically according to the location of grid voltage vector...
A bridgeless, two-inductor, interleaved Boost converter that possess voltage-doubler characteristic when it operates with a duty cycle greater than 0.5 for power factor pre-regulator is proposed in this paper. The conduction losses of the boost switches are reduced because at low line the converter operates in the voltage-doubler mode for almost the entire line period, which reduces the rms currents...
The mathematical model of the three-level PWM rectifiers is set up in this paper. By comparing it with the model of DC motors, some similarities are established. Based on the state feedback decoupling, the dual-loop close control scheme of DC motors is implemented to three-level PWM rectifiers. As a result, the three-level rectifier has favorable dynamic and steady state performance, sinusoidal input...
In this paper, the mathematical model of three-phase four-wire three-level neutral-point-clamped (NPC) voltage source rectifier (VSR) using switching functions is founded and its operating principle analyzed. Then a new nonlinear control law based on Lyapunovpsilas stability theory for the PWM rectifier is presented. With this control law, the converter can be stabilized globally for handling large-signal...
Passivity-based control (PBC) is based on a procedure including energy/power shaping and series/parallel damping injection to control several nonlinear systems such as power converters. In this paper, PBC is used to design a controller for three phase/level/switch PWM (Vienna I) rectifier. Passivity-based controller is supposed to regulate the output voltage and the input three phase sinusoidal currents...
This paper proposes a new circuit topology for a multilevel PWM rectifier. The proposed circuit combines a diode clamp type topology with a flying capacitor type topology. As a result, the proposed circuit uses only 12 switches, despite the use of a five-level three-phase PWM rectifier. Further, the proposed circuit can obtain good performance as same as to a conventional multilevel circuit. This...
This paper proposes a direct power control (DPC) strategy employed for the neutral-point-clamped (NPC) three-level PWM rectifier. Mathematic model of NPC three-level rectifier is conducted firstly as a theoretical base. This topology generates a higher number of output voltage levels, increasing the flexibility for selecting an appropriate voltage vector. The direct instantaneous power control technique...
To draw a sinusoidal line current and to achieve high power factor and low voltage stress of power switches, Some single-phase three-level switching mode unidirectional rectifiers with power diodes have been presented. But there is an inherited disadvantage of imbalance of the DC-link voltage, which is difficult to be solved only by control method. A novel three-level rectifier with asymmetrical legs...
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