Sinusoidal Pulse Width Modulation (spwm)

4. SINUSOIDAL PULSE WIDTH MODULATION The main goal of this control technique is to maintain constant voltage magnitude at the point where the sensitive load is connected, under the system disturbances. The control technique measures the rms voltage at the load point. The VSC switching technique is based on SPWM control which gives simplicity as well as good response.

Romli, M. S. N., Idris, Z., Saparon, A.(2008). An area-efficient Sinusoidal Pulse Width Modulation (SPWM) technique for Single Phase Matrix Converter (SPMC). 3rd IEEE Conference on Industrial Electronics and Applications, 2008. ICIEA 2008. Singapore: IEEE, 1163–1168.

STATCOM (DSTATCOM)[1] for power quality problems, like voltage sag and swell based on Sinusoidal Pulse Width Modulation (SPWM)[4] technique. A three-phase four-wire DSTATCOM (distribution static compensator) based on three-leg VSC (voltage source converter) and a star/delta transformer is proposed for power quality improvement. A harmonic current, reactive power and balances the load. Three single phase transformers are connected as star/delta transformer for interfacing to a three phase four-wire power distribution system and the required rating of the VSC [2] is reduced. However, a 4-leg VSC (voltage source converter[5]) based DSTATCOM (Distribution Static Compensator) is used for the load compensation and neutral current compensation in 3-phase 4-wire distribution system Power quality is an occurrence manifested as a nonstandard voltage, current or frequency that results in a failure of end use equipments. The major problems dealt here is the voltage sag and swell. To solve this problem, custom power devices are used. One of those devices is the Distribution STATCOM (D- STATCOM), which is the most efficient and effective modern custom power device used in power distribution networks. D- STATCOM injects a current in to the system to correct the voltage sag and swell. The control of the Voltage Source Converter (VSC) is done with the help of SPWM. The proposed D-STATCOM [11] is modelled and simulated using MATLAB/SIMULINK software [13].

This paper presents the design of a high-performance sinusoidal pulse width modulation (SPWM) controller for three phase uninterruptible power supply (UPS) systems that are operating under highly nonlinear loads. The classical SPWM method is quite effective in controlling the RMS magnitude of the UPS output voltages. However, it is not good enough in compensating the harmonics and the distortion caused specifically by the nonlinear currents drawn by the rectifier loads. The distortion becomes more severe at high power where the switching frequency has to be reduced due to the efficiency concerns. This study proposes a new design strategy that overcomes the limitations of the classical RMS control. It adds inner loops to the closed-loop control system effectively that enables successful reduction of harmonics and compensation of distortion at the outputs. Simulink is used to analyze, develop, and design the controller using the state-space model of the inverter. The controller is implemented in the TMS320F2808

This paper presents the implementation of sinusoidal pulse width modulation for a three phase Bridge inverter. Basically three sinusoidal reference signals which are phase shifted by120 degree apart from each other and compliment of these three sinusoidal signals are compared with the carrier signal to generate six different PWM signals for six switches of three phase inverter.LC filter is employed to reduce higher order harmonics in the three phase inverter output voltage. Closed loop operation is carried out. Hardware is implemented for open loop system where the SPWM algorithm is implemented in DSPIC30F2010. The efficiency of the inverter is high and offers less harmonic distortion. The proposed technique is simulated using MATLAB- Simulink model and THD is measured.

The performance of the conventional Multilevel Inverter topologies like Neutral- Point clamped Multilevel Inverter, Flying Capacitor Multilevel Inverter, Cascaded Multilevel Inverter have been checked with carrier based sinusoidal pulse width modulation. The extended version of flying capacitor Multilevel Inverter the Stacked Multicell Converter have also been examined to the carrier based sinusoidal pulse width modulation. The quality of the spectrum performance of the output waveform is checked by THD and utilization of the input DC voltage is checked by fundamental values of the output AC voltage. In level shifted modulation techniques that is PD, POD, and APOD the THD for out of three, the THD is found to be least with PDPWM. The fundamental value of phase voltage is found maximum in Stacked Multicell Converter Configuration.

Fig. 23: Circuit Diagram for PROTEUS Simulation These four pulses are gating the four MOSFETs of the full bridge inverter through the MOSFET driver. During the pulse A and C, MOSFET Q1 and Q4 will operate and during pulse B and D, MOSFET Q2 and Q3 will operate. This combination will produce SPWM voltage across the load of 50 Hz.

The SPWM technique can be implemented using microcontroller which is completely based on SPWM using sin reference and carrier reference waveform. But there is limitation of any microcontroller is that it can generate one carrier wave at a time which cannot be shifted to implement level shifted SPWM. Therefore in digital implementation samples of sinusoidal reference is taken at certain frequency. As the result sin waveform can be considered as sample and hold signal, which can be shifted according to level of output voltages have to be generated [7]. Accordingly the level shifted SPWM techniques can be implemented as follows.

components of the power semiconductor devices and cause to increase the switches stress. The multilevel carrier based on PWM, selective harmonic elimination and multilevel SVPWM are the switching control methods and always used in industrial applications and power electronics. The multilevel carrier based on PWM method is the most popular method due to easily implemented. This method can be categories into SPWM and SVPWM. The SPWM is comparing the references wave and the carrier wave to produce the pulse. The carrier based on PWM scheme are classified into phase shifted multicarrier modulation and level shifted multicarrier modulation. The SVPWM have the constant switching time calculations for each state and can easily be changed to higher level (C.Gomathi.et.al, 2013). This project focusses the SPWM as the switching control method.

Dissimilar types of PWM reins have been investigated in the journalism in [1]. Carrier Based PWM is the majority popular categories. But, carrier based PWM is frequently used for superior voltage steps. While the SVPWM are complicated for creating pulses for additional than 5-levels due to the job loss of switching state [12-15].Therefore, carrier based PWM control is preferred as the organize system for the projected topology in this expose. Variety of carrier based PWM is used to produce switching pulses in the projected topologies. In carrier based PWM scheme, several carriers (“m” level inverter ac output need “(m–1)” carriers) are created collectively which are constantly compared with sine reference signal and generate the PWM pulse [16].

[8] Waheed Ahmed, Syed M Usman Ali. “Comparative study of SVPWM (space vector pulse width modulation) & SPWM (sinusoidal pulse width modulation) based three phase voltage source inverters for variable speed drive”. ICSICCST 2013. IOP Conf. Series: Materials Science and Engineering 51 (2013) 012027. doi:10.1088/1757-899X/51/1/012027. [9] K. Vinoth Kumar, Prawin Angel Michael, Joseph P. John and Dr. S.

as an increase to between 1.1p.u and 1.8p.u in rms voltage or current at the power frequency durations from 0.5 to 1 minute [3]. A swell can occur due to a single line-to-ground fault on the system, which can also results in temporary voltage rise on the unfaulted phases. This is especially true in ungrounded or floating ground delta systems, where the sudden change in ground reference result in a voltage rise on the ungrounded phases. On an ungrounded system, the line-to ground voltages on the ungrounded phases will be 1.73p.u during a fault condition. Swells can also be generated by sudden load decreases and switching on a large capacitor bank often causes an oscillatory transient.. To solve this problem, custom power devices are used. One of those devices is the Dynamic Voltage Restorer (DVR), which is the most efficient and effective modern custom power device used in power distribution networks. Its appeal includes lower cost, smaller size, and its fast dynamic response to the disturbance. The Dynamic Voltage Restorer (DVR) is a power electronic device that is used to inject 3- phase voltage in series and in synchronism with the distribution feeder voltages in order to compensate for voltage sag [4] and similarly it reacts quickly to inject the appropriate voltage component (negative voltage magnitude) in order to compensate voltage swell. In this work, voltage sag and swell is compensated using DVR based on Space Vector Pulse Width Modulation technique (SVPWM). It is found that DVR based on Space Vector PWM technique (SVPWM) compensates voltage sags and swells effectively compare to Sinusoidal Pulse Width Modulation technique (SPWM).

CMLI requires control to operate like Table 1 and to result output voltage like equation (1). This control called modulation. Among modulation methods, CBPWM is the most popular method. This method is easily implemented, because the principle of CBPWM is similar to a single sinusoidal pulse width modulation (SPWM), which uses a triangular carrier and sine reference to generate the trigger signal [5]. Fig. 2 shows the basic principle of SPWM [7-9]. In SPWM, sine wave (V MOD ) compare to triangle carrier wave

Abstract- Inverters inherently have the property of controlling output frequency but the output volt- age can’t be varied. Usually to vary output voltage we have to vary supply voltage which is not always possible for this reason PWM techniques gained momentum. Basic aim of PWM technique is to control output voltage and harmonic reduction. Pulse-width modulation (PWM), or pulse- duration modulation (PDM), is a commonly used technique for controlling power to inertial electri- cal devices, made practical by modern electronic power switches. Here we apply PWM techniques like Sinusoidal pulse width modulation (SPWM) and Space Vector Pulse width Modulation (SVPWM) to inverter and study its performance.

Advances in power electronics have led to an increased interest in voltage source inverters with pulse width modulation control of AC drives. A number of pulse width modulation (PWM) schemes are used to obtain variable voltage and frequency supply. The most widely used PWM schemes for three-phase voltage source inverters are carrier- based sinusoidal PWM and space vector PWM (SVPWM). There is an increasing trend of using space vector PWM (SVPWM) because of their easier digital realization and better DC bus utilization [1-3]. Moreover, it gives a higher output voltage for the same DC bus voltage, lower switching losses, and better harmonic performance in comparison to carrier based sinusoidal pulse width modulation [4-5]. The space vector pulse width modulation of a three level inverter provides the additional advantage of superior harmonic quality and larger under-modulation range that extends the modulation factor to 90.7% from the traditional value of 78.5% in sinusoidal pulse width modulation. This paper focuses on SVPWM implemented on an induction motor drive. The model of a three-phase voltage source inverter is presented based on space vector theory.

ABSTRACT: The multilevel inverter topology gives the advantages of usage in high power and high voltage application with reduced harmonic distortion without a transformer. This paper presents a comparative study of nine level diode clamped inverter for constant Switching frequency of sinusoidal Pulse width Modulation and sinusoidal Natural Pulse width Modulation with switching frequency.

This paper presents a various modulation topologies are used to improve the power quality in Distributed Generation (DG) system. When the active filter is installed at a distorted and unbalanced distribution network, the harmonic are compensated by the active filter. The main advantage in this proposed method is incorporated V/F based induction motor control with Both SPWM and SVPWM based inverter. So that the advantages in 3-level with SVPWM as increased the performance and life time of drive. These advantages allow implementing controllers for electric vehicles; because, mainly electric vehicles need high starting torque so this is produce the required torque with minimum torque ripples and in electric vehicles, operation of drive is depends on variable torque with constant speed applications as well as variable speed with constant torque application.

The input controller consists of boost inductor Lin, boost diode Dx1&switch S4 which is shared by multilevel dc-dc section. It performs PFC &regulates primary of dc bus capacitors by sending appropriate signals to S4 which is done by controlling D2& then adding the duty cycle of D2 to D1(D1&D2 are shown in fig 2). Besides regulation of dc bus voltage is done by sending gate signals to S1 to S4 by controlling duty cycle of D1.In short S4 perform two tasks (D1) participate in control of output voltage and other part (D2) regulate dc bus voltage. The switches S2 and S3 are ON for half a switching cycle, but are never ON at the same time. In the figure the diode rectifier bridge output is replaced by a rectified sinusoidal source (Vrec) and the thick lines represent the paths of current conduction.

The various pulse width modulation techniques for controlling the multilevel inverter topologies are step modulation, sinusoidal PWM, space vector modulation, selective harmonic PWM, modified sinusoidal PWM and multiple pulses PWM. Among this space vector PWM is now used in research and development areas but its algorithm is very complex having many number trigonometric functions, so this has less preference to use in the practical implementation.

The main purpose of using modulation technique for power semiconductor devices is to create the switching signals in such a way that the output fundamental voltage waveform is merely like the sinusoidal waveform. Henceforth by attaining the output voltage waveform shape same as the sinusoidal waveform, we can bring down the lower order harmonics which in turn lessen the total harmonic distortion (THD) of the entire circuit. Based upon the switching frequencies used the MLIs are categorized as given below. Fig 1 displays the various types of modulation techniques. In this paperwork we have implemented level shifting pulse width modulation (PD) modulation technique to generate the desired output waveform.