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In this paper zero-vector intervals of eight-segment PWM scheme based on space vector modulation (SVM) is optimized for three-phase isolated buck matrix-type rectifier. With the proposed non-equally distributed zero-vector intervals of eight-segment PWM scheme, the output inductor current ripple of the converter is reduced comparing to that of the equally distributed zero-vector intervals. The steady...
Multilevel current source converter (MCSC) is an effective way to increase the power rating of conventional current source-fed motor drive, especially its current rating. However, there are still several challenges existing in this kind of configuration, which mainly focus on its space vector modulation (SVM) technique and the inherent DC current imbalance issue. In this paper, an SVM scheme with...
In this work, a Model Predictive Control (MPC) strategy that combines Finite-Control-Set MPC (FCS-MPC) with Selective Harmonic Elimination (SHE) modulation pattern in its formulation is proposed to govern power converters. The key idea here is to define a desired steady-state in terms of the converter current and voltage. To do this, based on the converter current (system state) reference, an associated...
CSC topology with natural advantages in terms of simple structure, grid friendly waveforms, controllable power factor, and reliable grid short-circuit protection is considered to be a promising converter configuration for use in mediumvoltage (kV) high-power (MW) PMSG based wind energy systems. In view of this, three types of configurations for current source converter (CSC) based medium-voltage PMSG...
A simple flying-capacitor voltage balancing method for nested neutral point clamped (NNPC) inverter is proposed in this paper. The NNPC inverter is a newly developed four-level voltage source inverter (VSI) with new topology. There are two flying-capacitors in series in each leg in the NNPC inverter. The voltage across each capacitor should be controlled to balance at one-third of DC bus voltage to...
The modular multilevel converter (MMC) has several three-level flying capacitor (3L-FC) submodules in cascade. To balance the submodule capacitors voltage, this paper describes a dynamic voltage balancing algorithm based on the carrier phase shifted pulse width modulation (CPS-PWM) scheme. The submodules are controlled based on the instantaneous value of capacitor voltage and the direction of current...
In this paper, two fast acting dc circuit breakers are investigated to interrupt the short-circuit faults in HVDC transmission lines. These circuit breakers are realized using dc/dc choppers which can also perform step-up and/or step-down functions. Compared to the existing topologies, the number of active switches in the proposed configurations are minimized to achieve lower initial cost and higher...
An interleaved bidirectional switched capacitor converter with regulation capability is proposed in this paper. This converter is able to step up the voltage to near three times and regulate the output, while maintaining continuous input current as well as small output voltage ripple. Due to its natural interleaved structure, fewer components are required compared with traditional interleaved switched-capacitor...
This paper proposes a novel control technique to improve the power factor over a wide range of wind speed in a wind energy conversion system (WECS) based on a current source inverter (CSI) and an electrically excited synchronous generator (EESG). The system consists of diode rectifier on the generator-side while a pulse wave modulated (PWM) CSI is on the grid-side. In the proposed control scheme,...
The performance of full-color LED display is related with refresh rate, This paper presents a advanced scan mode based on dispersed PWM, and illustrates the algorithm to disassemble a PWM pulse into many regular narrow pulses. This scan mode can provide very high dynamic refresh rate rather than fixed frequency, eliminate flicker effect even as low frame frequency and expand gray-scale depth .This...
The voltage-boost characteristic of the pulse-width-modulated (PWM) current-source inverter (CSI) is in accordance with the nature of a variable-speed wind energy conversion system (WECS). In view of this, low-cost power converter solutions using diode/thyristor rectifier with PWM CSI are proposed and investigated in this paper for wind power generation applications. Detailed steady-state analysis...
A new interconnecting approach for an offshore wind farm is used, where same number of cascaded pulse width modulated (PWM) current source converters (CSCs) are used on both generator and grid side. This paper presents a novel control scheme which enables maximum power acquisition from the wind for every wind turbines in the wind farm and aggregate power is equally shared by the grid side CSCs with...
A novel converter configuration is proposed in this paper for mega-watt wind energy conversion system (WECS) using permanent magnet synchronous generator (PMSG). The converter consists of a diode rectifier, a buck converter and a pulse-width-modulated (PWM) current source inverter (CSI). Two DC current requirements in the system are analyzed and compared: one from the generator and diode rectifier...
This paper presents a novel interconnecting approach for an offshore wind farm, where pulse width modulated (PWM) current-source converter(CSC) of each wind generator is series connected and dc output is fed by submarine cable to the series connected PWM CSCs on grid side. The total number of series connected PWM CSCs for the onshore grid connections are equal to the number of wind generators installed...
Half-wave symmetry SHE-PWM method has a large number of valid solutions, which are beneficial to optimization design. This paper proposes a novel generalized formulation of half-wave symmetry SHE-PWM problems for multilevel inverters. The advantages of the proposed formulation include simplicity in format, flexibility in PWM waveforms and a broad solution space. Methods to obtain initial values for...
Multilevel converters are used in medium voltage high power applications. In this field, switching losses are an important efficiency issue due to long term operation costs. Previous works have centered the analysis in comparing different topologies or semiconductors in relation to switching losses. However, switching loses are closely related to the modulation method employed to control the converter...
A novel formulation of quarter-symmetry SHE-PWM problems for five-level voltage inverters is proposed. The SHE modulation scheme features a broad solution space and can eliminate a large number of low-order harmonics. An effective method for obtaining initial values of switching angles is proposed. To illustrate the effectiveness of the proposed SHE method, a five-level voltage source inverter with...
The need to increase the amount of mineral being processed has originated the use of high power converters (HPC), many of them in the Megawatt range. There are several design aspects which must fulfill the operational requirements, which mean technical challenges for designers, manufacturers and operators. This paper presents the general requirements for high power drives applied to the most used...
Summary form only given: A novel dc voltage detection technique, referred to as single multiple-voltage (SMV) detector, is developed to obtain dc capacitor voltages in the cascaded H-bridge (CHB) multilevel inverter-based static synchronous compensator (STATCOM). Based on the proposed SMV algorithm, the number of voltage sensors is substantially reduced. Only three voltage sensors are required to...
A novel three-phase PWM rectifier-inverter topology for UPS applications is proposed in this paper. The topology uses only nine IGBT devices for AC/AC conversion through a quasi DC link circuit. This converter topology features sinusoidal inputs and outputs, unity input power factor, and more importantly, low manufacturing cost. The operating principle of the converter is elaborated and a novel modulation...
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