PULSE WIDTH MODULATION OBJECTIVE AND SIGNIFICANCE In this project, we would like to study more on

This chapter deals with the classification and basic operation of electric variable speed drive system and scope, merits and demerits of DC and AC drives. Then AC induction motor drive is selected for complete description. Here AC drive system is presented with its components like inverters, position sensors and current controller.

A phase-locked loop (PLL) generates a signal that has a fixed relation to the phase of a reference signal and is given in Fig. 4. A phase locked loop responds to both the frequency and the phase of the input signals, automatically raising or lowering the frequency of the controlled oscillator until it is matched to the reference in both frequency and phase. Here three phase PLL was implemented with three basic functional blocks: the phase detector, a PI controller and a voltage controlled oscillator. The phase detector is a circuit capable of delivering an output signal that is proportional to the phase difference between its two input signals. The PI controller is a low pass filter and used to suppress high frequency component and provide dc controlled signal to voltage controlled oscillator which acts as an integrator. The output of the PI controller is the inverter output frequency that is integrated to obtain inverter phase angle θ. When the difference between grid phase angle and inverter phase angle is equal, Vq =

Fig. 11 shows a comparison of DPWM2O, DPWMLPF2 and GDPWMO at 0.4 modulation index. The inverter is operating with 160 Hz fundamental frequency and 7.68 kHz switching frequency. The output power factor angle is 45°. It can be seen that each strategy produces 32 pulses in one cycle. However, the clamping interval of the GDPWMO strategy is perfectly aligned with the line current peaks, whereas the DPWM2O and DPWMLPF2 strategies incurs switching instances around the current peaks.

Single loop control methods allowed a single voltage control loop to regulate the output voltage. The input current shaping is accomplished in an open loop manner, the duty cycle patterns are predefined by considering in ideal PFC operation. One example in this control method is the duty phase control (DPC) proposed by Chen [42]. In this method, a phase shift is willingly introduced to the stored duty cycle patterns. The output voltage is regulated by adjusting this phase shift by using the output of the voltage error amplifier, which is named “the duty phase”. This approach simplified the control structure and eliminated the current loop, without the need to

Space Vector PWM (SVPWM) refers to a special switching sequence of the upper three power transistors of a three-phase power inverter. It has been shown to generate less harmonic distortion in the output voltages and or currents applied to the phases of an AC motor and to provide more efficient use of supply voltage compared with sinusoidal modulation technique. The biggest difference from other PWM methods is that the SVPWM uses a vector as a reference. This gives the advantage of a better overview of the system.

Nowadays, because of the fast evolution of electronic device, The recent developments in permanent magnet materials, solid state devices and microelectronic have led to the appearance of a new energy efficient drives using permanent magnet brushless direct current motors (PMBLDCM).

Keywords: CUK Bridgeless Topology, Fuzzy Logic Controller (FLC), Power Factor Correction (PFC), Proportional- Integral (PI) Controller.

They are distinguished by their structure and their control strategy in order to constrain the shape of the wave of the absorbed currents. They can be divided into three classes: single phase diode rectifier followed by a PFC (Power Factor Correction), rectifier with current injection (composed of a three-phase diode rectifier equipped with a modulation circuit and d A distribution circuit for the injection of currents required in the network), and the Boost PWM Rectifier using a voltage inverter bridge[5][6] [7].

Output Voltage of the Inverter can be modified or controlled by controlling or modifying switching current, or in case of Power Switches, by controlling or modifying Gate current. This control is achieved by PWM control. In one of the methods of controlling inverter output voltage, a fixed DC voltage is given to the inverter and by varying the ON and OFF time of power switches we get a controlled or modified AC output voltage. This method is popularly called as Pulse Width Modulation (PWM) method. The features of PWM inverter can be summarized as follows

ABSTRACT: Power flow control in a long transmission line plays a vital role in electrical power system. This paper uses the shunt connected STATCOM for the control of voltage and power flow. The proposed device is used in different locations such as sending end, middle and receiving end of the transmission line. The PWM control is used to generate the firing pulses of the controller circuit. Simulation modeling of the system is carried out using MATLAB/SIMULINK. Based on a voltage-source converter, the STATCOM regulates system voltage by absorbing or generating reactive power. This paper deals with a cascaded multilevel converter model, which is a 48-pulse (three levels) GTO converter. The simulation studies are carried for sending end, middle and receiving end of the transmission line. The objective is to define the reactive power generated and voltage control at different locations (at sending end, middle, receiving end) of transmission line using STATCOM. KEYWORDS: FACTS device, STATCOM, SVC, PWM, MATLAB /Simulink.

Student: Vishal Kasotia Project Guide: Mr Ajay Sharma. College: Indian Institute of Technology Roorkee Course: Electrical Engineering with Specialization in Power Electronics (EPE) Enrolment Number: 12212014 Internship Period: May 11, 2015 – July 3, 2015

Key words – i) Effect of series resistance ii) i-v characterstics iii) Power region iv) Power Plane Analysis v)Maximum Power Point Tracking.

Abstract— This paper presents study and comparison of Maximum Power Point tracking(MPPT) for photovoltaic applications. Comparison based on the output power from the Photovoltaic panel(PV),ripple in PV voltage,Tracking Efficiency and oscillations around the MPP. Using Power Simulation(PSIM) platform, the conventional MPPT algorithms and proposed MPPT algorithm is compared with boost converter. The simulation results for conventional MPPT algorithms and proposed MPPT algorithm named power plane analysis technique with and without using Proportional Integral(PI) controller are computed.

Automatic Power factor correction device reads the power factor from voltage and current, calculating the compensation requirement switch on different capacitor banks. So in our work we are going to design a control panel which will provide a nearer unity Power Factor When Plant

This project has been carried out at the department of the electrical engineering at S.V.I.T. Vasad. It has been great opportunity to work with this project and get knowledge about this area of the power electronics.