Earticle

Aiming at the problem that the theoretical spectrum expression of the output voltage waveform in the space vector pulse width modulation strategy is often extremely complicated, most tedious and quite error-prone, the study develops a universal procedure and algorithm with adaptive precision to analyze the harmonic spectrum. The key steps and technique of the procedure and algorithm are given firstly. The algorithm steps include storing the switching states and the vector sequences, computing the basic space vector duration time, storing the duration time, sampling output voltage values and computing the spectrum using the fast Fourier transform algorithm. The sampling number doubles in each iteration for the next iteration. The adaptive precision is realized through controlling the amplitude or magnitude error between the current result and the previous result. The realization method and the key codes are presented secondly. Finally, three numerical experiments are presented to verify the developed algorithm, and the results verify its correctness, reliability and convenience.

Decoupling control of two-motor dual three-phase permanent-magnet synchronous motor (PMSM) series-connected system can be realized by using proper phase transposition rules with a single supply from a six-phase voltage source inverter (VSI), which solved the control problem of two motors in series. Since the traditional two-vector SVPWM strategy, which is commonly used in three-phase system, exists 5th and 7th harmonics in x-y plane, making it hard to realize decoupling control of two-motor dual three-phase PMSM series-connected system. Meanwhile, the DC bus voltage utilization of carrier-based PWM strategy is lower. Thus one method, which adopted a TBTSB-SVPWM strategy with two modulators, was proposed in this paper. It ensures the inverter output voltage only contains two kinds of fundamental components required by the two series-connected motors with a single VSI, making it possible to realize decoupling control of two-motor dual three-phase PMSM series-connected system. Simulation results indicate that there is no influence on the other motor while the speed/load of any one motor changed, achieving the decoupling control of series-connected system, and the feasibility and validness of the proposed approach are verified.

Using variable speed engine in diesel generator will enhance efficiency of the engine where it will operate continuously at its optimum speed. The high cost of variable speed diesel generator because of using power electronic elements to convert variable frequency voltage to constant frequency voltage (AC/DC-DC/AC)cane be reduced if we use Hybrid System by connecting the PV system to DC Voltage bus directly and using it’s inverter as main inverter of the system studied in this paper is consisted of a Photovoltaic and a Variable Speed Diesel engine driving PMSG .By using FOC we can control the output power of PMSG according to the speed of the engine and vice versa .The change of climatic condition is the main problem of renewable energy specially when the engine–generator operate at it is minimum speed for that SMES which an high power density storage element is used for maintaining the stability of the stability of the system. The simulation of the system was done using Matlab/Simulink and the result of the simulation was discussed.

Aiming at complicated characteristic analysis and implementation of the randomization space vector pulse width modulation (SVPWM) scheme, a new random zero-vector SVPWM scheme with a fixed randomization range is proposed. The fixed range is a linear function of the modulation index. Firstly, the principle of the new scheme is given. In addition, the implicit modulating voltages, the derivation procedure of the micro and macro harmonic distortion factor (HDF) are presented in detail, and the Monte Carlo method is proposed to efficiently analyze the HDF. Finally, the harmonic spectrum of the new scheme is analyzed compared with the commonly used symmetrical 7-segment SVPWM scheme through an example, and the result verifies its excellent performance on suppressing the cluster harmonic magnitude around the integer multiple switching frequency.

In this study, a generalized space vector pulse width modulation (SVPWM) method is proposed for cascaded H-bridge multilevel inverters. An explicit modulation function expression of the generalized SVPWM method is established for a single-stage cascaded inverter. Various continuous SVPWM and discontinuous PWM methods are obtained easily by changing the zero vector distribution coefficient. The generalized SVPWM method for cascaded multilevel inverters is achieved via the carrier phase shift strategy. A simple digital realization method for the generalized SVPWM is also proposed. By using this method, complex trigonometric function calculations, coordinate transformations, space vector selections, and duration time calculations are avoided. Finally, the simulation model and experimental device of the eight cascaded multilevel inverters are built to test the proposed method. The harmonic characteristics of the different modulation method are also analyzed. Simulation and experimental results demonstrate the feasibility and effectiveness of the method.

Space vector pulse wide modulation(SVPWM) have less harmonic than SPWM, it is easy to digitalize, and it is used in high voltage field more and more. In this paper, the principle is analyzed detailed, and simulated by Simulink, the simulation result show that the space vector pulse wide modulation scheme is feasible. The SVPWM power system hardware and software is designed at last.

The spectrum of the random space vector pulse width modulation (SVPWM) strategy is extremely complicated due to the random variable. A new algorithm based on the Monte Carlo method is proposed to optimize and customize the frequency spectrum of the random SVPWM strategy. A universal theoretical spectrum computation method is given for the SVPWM strategy firstly. In addition, the key procedure of the proposed algorithm is presented. Finally, several computation examples are provided to verify the effectiveness and feasibility. The analysis and computation examples show that the proposed algorithm has several advantages, and the results verify its convenience and feasibility.

This paper presents an optimized space vector pulse-width modulation (OSVPWM) technique for a five-level cascaded H-bridge (CHB) inverter. The space vector diagram of the five-level CHB inverter is optimized by resolving it into inner and outer two-level space vector hexagons. Unlike conventional space vector topology, the proposed technique significantly reduces the involved computational time and efforts without compromising the performance of the five-level CHB inverter. A further optimized (FOSVPWM) technique is also presented in this paper, which significantly reduces the complexity and computational efforts. The developed techniques are verified through MATLAB/SIMULINK. Results are compared with sinusoidal pulse-width modulation (SPWM) to prove the validity of the proposed technique. The proposed simulation system is realized by using an XC3S400 field-programmable gate array from Xilinx, Inc. The experiment results are then presented for verification.

In this paper, maximum boost space vector pulse-width modulation(MBSVPWM) strategy of Z-Source Inverters(ZSIs) is proposed. Conventional space vector pulse-width modulation(SVPWM) method of Voltage Source Inverters(VSIs) is modified to produce unique PWM patterns that realize the maximum boost control of ZSIs. This proposed method minimizes the switching power losses of ZSIs by reducing the numbers of the shoot-through states. Moreover, some switches keep ON state and the switching transitions do not occur during the specific sectors. An experimental system has been built and tested to verify the effectiveness of the proposed strategy.

본 논문은 공간벡터 변조 방법에서부터 Six-step 동작까지의 새로운 과변조 방법을 제시하였다. 극전압을 푸리에 시리즈를 이용하여 분석하였고 지령 상전압에서부터 펄스 폭 변조 스위칭 신호까지의 알고리즘을 제안하였다. Matlab 시뮬레이션을 통해 검증하였다.

The space vector pulse width modulation (SVPWM) technique is a popular PWM method for medium voltage drive applications. Conventional SVPWM (CSVPWM) and bus clamped SVPWM (BCSVPWM) are the most common SVPWM techniques. This paper evaluates the performance of various advanced BCSVPWM strategies in terms of their harmonic distortion and switching loss based on a uniform frame work. A uniform frame work, pulse number captures the performance parameter variations of different SVPWM strategies for various number of samples with heterogeneous pulse numbers. This work compares different advanced BCSVPWM techniques based on the modulation index and location of the clamping position (zero vector changing angle ) of a phase in a line cycle. The frame work provides a fixed fundamental frequency of 50Hz. The different BCSVPWM switching strategies are implemented and compared experimentally on a 415V, 2.2kW, 50Hz, 3-phase induction motor drive which is fed from an IGBT based 2 KVA voltage source inverter (VSI) with a DC bus voltage of 400 V. A low cost PIC microcontroller (PIC18F452) is used as the controller platform.

Two major obstacles in the utilization of electrical vehicles are their price and range. The collaboration of direct torque control (DTC) with induction motor (IM) is preferred for its low cost, easy implementation, and parameter independency. However, in terms of edges, the method has drawbacks, such as variable switching frequency and undesired current harmonic distortion. These drawbacks result in acoustic noise, reduced efficiency, and electromagnetic interference. A feed-forward approach for stator-flux-oriented DTC with space vector pulse-width modulation is presented in in this paper. The outcome of the proposed method is low current harmonic distortion with fixed switching frequency while preserving the torque performance and simple application feature of basic DTC. The method is applicable to existing and forthcoming IM drive systems via software adaptation. The validity of the proposed method is confirmed by simulation and experimental results.

In this paper, space voltage vector pulsewidth modulation for 2-phase inverter is proposed. When this method is appled to 2-phase induction motor, the phase difference of voltage between phase A and B is fixed at $90^{\circ}$and amplitude of voltage of phase Ais same with that of phase B. This method have advantages over low-power servo system because this is simple method comparing to 3-phase space vector method which requires d-q transform.