Description Of The Reference Voltage Vector

Pulse width modulation or PWM is the basic analysis for control modulation in the power electronics. PWM is a powerful and commonly used technique for controlling the analog circuits or power to electrical devices and made practical by a processor’s digital output such as the modern electronic power switches. Theoretically, the zero rise time and fall time of an ideal PWM, waveform represents a way of driving latest semiconductor power devices. Except for the resonant converters, majority of power electronics circuits are controlled by PWM signals of several forms.

To measure the similarity of each two successive cycles for the same electrical signal (current/voltage/power), the author proposes to apply the correlation concept [21-24]. The correlation coefficient (r) is computed between a window with a certain number of samples (m) in a signal (X) and another window with the same number of samples in the same signal but shifted from each other by a time interval of hΔt, where m is the number of samples per window, h is the number of samples between the two windows which are shifted from each other and Δt is the sampling interval time. Equation (1) shows the correlation coefficient (r) for signal X. When hΔt = 0, then h =0 and the correlation function (r) calculated between the two same windows of signal Xk is unity.

[2] E. H. Kim and B. H. Kwon, “Zero-voltage- and zero-current-switching full-bridge converter with secondary resonance,” IEEE Trans. Ind.Electron., vol. 57, no. 3, pp. 1017–1025, Mar. 2010.

To further explore possible outcomes, Case 1 was repeated while varying the load modeling. The first modification that was made was to model all the loads as constant current. The resulting voltage profile is shown in Figure 3.5.1. Unexpectedly, the number of iterations required to achieve the minimum error specification for this load model was much higher than initially predicted. One possible explanation for the increase in iterations is an error in the load modeling portion of the simulation, though one could not be found. Regardless of error, the results have changed from the first case shown in Figure 3.1.1. From this, it can be concluded that the load modeling affects the voltage profile.

switch allows rail-to-rail swings. The transconductance of TG gate switch is expressed by the following

Power electronic circuits that convert a dc voltage to difference dc voltage level are known as the DC-DC converters. It uses semiconductor devices to perform its operations by controlling or modifying a voltage current. There are different types of conversion method such as electronic, linear, switched-mode, and so on. Whenever we want to change DC electrical power from one level to another level, switched-mode DC-DC converter has been chosen because is much efficient due to the reduced losses in the electronic switch. Switched-mode DC-DC converters is also known as switching power supplies or switchers.

As per references [2], [6], [7], [9] any device with nonlinear characteristics which derive their input power from a sinusoidal electrical system may be responsible for injecting harmonic currents & voltages into the electrical system [2, 6, 7, 9 ]. Francisco C. De la rossa [2] have described ,all possible nonlinear loads . Among them few are Power converters such as Variable frequency drives, DC motor controllers, Cycloconverter, Cranes, Elevators ,Steel mills, Power supplies, UPS,Battery chargers, Inverters & ARC devices such as Fluorescent lighting, ARC furnaces, Welding machines. According to authors [2] ,[7] Even linear loads like power transformers can act nonlinear under saturation conditions. This occurs beyond the so-called saturation knee of the magnetizing curve of the transformer. [2],[7].

The switching component of power is independent of the rise and fall time of the logic gates. However, the finite rise and fall times of the input waveforms result in a direct current path between VDD and GND for a short period of time and both PMOS and NMOS devices are ON. Such kind of behaviour leads to incorrect evaluations.

where d0 is a reference distance at which or closer to the path loss inherits the characteristics of

In this method three modulating signals ( mR for R-phase, mY for Y-phase, mB for B-phase) with 120 degree phase shift when compared with high frequency carrier triangular signal it generates switching pulse.

turn-OFF, and DCM. Three modes are shown in Fig. 2 and their associated waveforms are shown in Fig. 3. These

Also equation for instructions using immediate data is developed. R2 value of 0.9 is obtained.

and high-power applications. For closed loop speed control operation, in current control loop, three phase stator current information is required. The current sensors and the associated accessories increase the complexity of the system, cost and size of the motor drives and decrease the reliability of the system and also more number of power electronics switches means more switching losses and costly. Therefore to overcome this problem a new drive system is proposed which uses four switches and two current sensor, less switches and less current sensors means less switching losses and low cost. In this paper, the PWM technique is therefore proposed to minimize the torque ripple and designed to overcome the disadvantages from other torque ripple

1Department of Electronics and Telecommunications, Symbiosis Institute of Technology, Symbiosis International University, Pune 412115, Maharashtra, India

Abstract—This paper proposes direct torque control of induction motor simulation using conventional method and space vector pulse width modulation technique for ripple reduction. Direct Torque Control (DTC) is a control technique used in AC drive systems to obtain high performance torque control and thereby controlling the speed of induction motor. The