Generalized Scalar PWM Algorithm for VSI Fed Induction Motor Drives with Reduced Complexity

The aim of this paper is to obtain the AC voltage from DC source with the help of Space vector based Inverter. In a space-vector PWM (Pulse Width Modulation) inverter, which is widely used, the voltage utilization factor can be increased to 0.906, normalized to that of the six step operation. Three phase voltage-source pulse width modulation inverters have been widely used for dc/ac power conversion since they can produce a variable voltage and variable frequency power. However, they require a dead time to avoid the arm-short and snubber circuits to suppress the switching spike. Apart from these ancillary aspects, the PWM inverters have an essential problem that they cannot produce voltages as large as the six-step inverters can. That is, the dc bus voltage cannot be utilized to the maximum. To increase the voltage utilization of the sinusoidal PWM inverter, a method of the addition of the third harmonics to the reference voltage was proposed by which the fundamental component can be increased by 15.5%. In a space-vector PWM inverter, which is widely used, the voltage utilization factor can be increased to 0.906, normalized to that of the sixstep operation. On the other hand, different discontinuous PWM strategies were analyzed, where the modulation waveform of a phase has at least one segment of 60 which is clamped to the positive and/or negative dc bus for, at most, a total of 120 in a fundamental period during which no switching in either inverter arm occurs. Recently, it is shown that discontinuous PWM schemes and the space-vector PWM can be obtained by properly adding a zero-sequence voltage to the original modulation waveform.

In this paper, a pulse width modulation (PWM) generator based on a switched capacitor for LCD backlight brightness control is described. The proposed scheme uses a simple RC network along with a clocked-comparator which samples the output of the ambient light sensor, and generates a PWM signal corresponding to the light level. Furthermore, by using a switched-capacitor resistor with variable clock frequency, the RC time constant is programmable and less sensitive to process variations with respect to passive resistors. In addition, it is shown that the linearity of the proposed PWM generator can be enhanced by replacing the RC network resistor with a constant current source. The operation of the PWM generator is verified through circuit level simulations, and the prototype circuit is fabricated using CMOS 0.18um technology.

This paper presents a control for a three-phase an eleven-level cascaded H-bridge inverter for photovoltaic (PV) system. The maximum power point tracking (MPPT) is capable of extracting maximum power from the PV array connected to each DC link voltage level. The MPPT algorithm is solved by fuzzy logic controller. Space vector pulse width modulation (SVPWM) algorithm uses a simple mapping to generate gate signals for the inverter. This is done to achieve high dynamic performance with low total harmonic distortion (THD). The validity of the system is verified through MATLAB/Simulink and results are compared with three-phase three-level, five-level, seven-level and nine-level cascaded H-bridge inverter for PV system in terms of THD. Finally, simulation results are presented to verify the effectiveness and accuracy of the proposed system.

In order to improve the control result of three phase motor with power supplied by battery, it uses voltage vector control technology to control the three-phase motor excitation current and the torque current respectively. At the same time, according to the principle of rotor flux oriented, it get the aim of measuring and controlling the vector of three phase motor stator current. The research on the way of achieving the algorithm of the voltage space vector pulse width modulation is detailed introduced. By building the simulating model of three-phase asynchronous motor, it simulates the algorithm. As a result, it shows that the algorithm is reasonable, the control performance is better and application requirements of control for three-phase asynchronous motor with power supplied by battery is satisfied.

The first fully integrated GaN pulse width modulation (PWM) generator for power conversion applications is presented in this paper. The solution is implemented in a 0.5-μm technology, avoiding additional pins and external capacitors for sawtooth signal generation while providing high accuracy. Indeed, the large GaN process spreads are addressed through an innovative dynamic offset compensation approach whose clock signal takes advantage of the PWM signal itself. The proposed PWM generator adopts a 6-V power supply and includes a 25 digital divider to set the PWM frequency at 500 kHz and the minimum and maximum duty cycles at 6% and 94%, respectively. Experimental results on integrated prototypes validated the correct circuit functionality over the temperature range from -40°C to 120°C. As a main achievement, this work demonstrates effective all-GaN integration of complex mixed analog and digital circuits, thus representing a significant advancement in the approaches to overcome the main limitations of GaN devices and enable fully integrated signal processing implementation.

An analytical evaluation method for output waveform quality of space vector pulse width modulation (PWM) strategies applied in neutral-point-clamped three-level converter (3L-NPC) is proposed in this paper. Low frequency error caused by neutral point voltage ripple and high frequency error introduced by space vector synthesis were both taken into account, and the unified error model of output current ripple was established. By taking continuous and discontinuous modulation strategies as examples, the unified error model was validated through Fourier analysis of the experimental results. The proposed evaluation method will be helpful for the switching sequence optimization and the modulation strategy selection.

Recently, The necessity of renewable energy be on the rise in as fossil fuel is depleted. Study of offshore wind power generation is being carried out as part of the renewable energy business. The 3-level inverter for use in the offshore wind power system studied is increasing as high capacity about offshore wind power. The 3-level inverter had an advantage that make reference voltage higher than 2-level reference voltage. Also, study of the 3-phase inverter has increased nowadays. However, 3-level NPC (Neutral-Point-Clamped) inverter, two capacitors and the neutral point are connected in series, it can lead to problems reduces stability of the system and unbalance voltage. It is SVPWM (Space Vector Pulse Width Modulation) method. Because DPWM (Discontinuous Pulse Width Modulation) method didn't neutral point control as same method from SVPWM, each DPWM method need a method of neutral point control. This paper proposed a method of applying the offset voltage attem pts to resolve the difficulties of the neutral point voltage control. The equation for the offset voltage to be applied to the system of each DPWM was determined. The proposed method is implemented by comparison of block diagram. The proposed algorithm is verified by the simulation.

This paper presents a comparison of two chaoized PWM algorithms for motor drives in the electric vehicle (EV), which are the chaotic sinusoidal pulse width modulation (SPWM) and the chaotic space-vector pulse width modulation (SVPWM). The SPWM scheme can be chaoized by three modulation methods, including the chaotically amplitude-modulated frequency modulation (CAFM), the chaotically position-modulated position modulation (CPPM), and the hybrid chaotic frequency modulation (HCFM), while the chaotic SVPWM can be fulfilled by the chaotically frequency-modulated frequency modulation (CFFM) and the CAFM methods. The performance indexes used in the comparative analysis are the electromagnetic interference (EMI) and the mechanical resonance (MR). The chaotic PWM algorithm is designed and implemented to increase the electromagnetic compatibility (EMC) and the mechanical performance for EV motor drives, and the aforementioned performance indexes are compared for the practical applicability.

Induction motors run at rated speed and are used widely in the applications of conveyors, pumps, cranes, compressors, etc. Some applications need variation in speed of operation. Speed control can be achieved by various control methods and also by designing suitable controllers. Moreover, many control strategies dealt with the control of speed regulation, flux optimization, power factor correction in induction motor drive. Hence proposed system is designed by the Space Vector Pulse Width Modulation (SVPWM) technique using a PID controller where the performance of the system has been improved. In Sinusoidal Pulse Width Modulation (SPWM) oscillations are more in torque waveform when compared to SVPWM. When torque increases speed will be decreased. This is the main drawback of the closed system of SPWM. Hence the performance is predicted by using voltage source inverter fed by three-phase induction motor drive using the PID controller. Simulation results are obtained using MATLAB/SIMULINK.

This thesis presents design and implementation of a 20 kVA division-summation (D-Σ) digital controlled three-phase four-wire multi-function inverter system. The in-verter can be operated in grid-connected or stand-alone mode to act as a renewa-ble-energy ac power-supply system. In the stand-alone mode, the control of this in-verter uses the D-Σ digital control law for voltage tracking which includes load im-pedance estimation and repetitive control, causing the inverter can stabilize sinusoidal output voltage for unbalanced load and nonlinear load. For the grid-connected mode, in order to achieve a specific PF and stabilize grid voltage and frequency, the control is the D-Σ digital control law for current tracking which supplemented by a droop control based linear P-Q compensation. Moreover, the D-Σ digital control law in this research is based on Two-Phase Modulation (TPM) scheme and associated with the switching sequence transformed from space vector pulse width modulation (SVPWM) scheme, and thus, the inductance variation can be taken into account, reducing core size significantly. Finally, the control laws are verified with measured results from a 20 kVA three-phase four-wire inverter system.

SVPWM control strategy for a three phase five level dual inverter fed open-end winding induction motor

Multilevel inverters are increasingly being used in high-power medium voltage industrial drive applications due to their superior performance compared to conventional two-level inverters. Thre are a number of Pulse width modulation (PWM) techniques applied in recent years. The most widely applied PWM techniques are Sine Pulse Width Modulation (SPWM) and Space Vector Pulse Width Modulation (SVPWM). SPWM is the most simple modulation technique that can realize easily in analog circuit. However, it has some drawbacks such as higher total harmonic distortion (THD), lower effective DC utilization and lower switching frequency. Space vector pulse width modulation (SVPWM) is widely used because of their easier digital realization and better DC bus utilization and lower THD. The complexity is due to the difficulty in determining the reference vector location, on times calculation, and switching states selection. This paper presents a simple SVPWM algorithm for diode clamped three level inverters based on standard two-level SVPWM which can easily determine the location of reference vector, calculate the on-times, the selection of switching states. Three level diode clamped inverter (3LDCI) using space vector modulation technique has been modeled and simulated using MATLAB/SIMULINK and Origin 6.1 with a passive R-L load that can be extended to any level. Simulation results are presented to verify the proposed SVPWM control in terms of THD. The results are compared with conventional sinusoidal pulse width modulation (SPWM) where SVPWM shows better performance than SPWM in terms of THD. DOI: http://dx.doi.org/10.11591/ijpeds.v5i1.6038

In this paper, a novel approach to realize the carrier-based pulse width modulation (CBPWM) method for indirect matrix converter (IMC) is presented. The advantage of the proposed CBPWM method is that only one triangular carrier signal with constant gradient falling and rising edges is used to generate the PWM to the power switches in both the rectifier and the inverter stages of IMC. The analysis of the proposed CBPWM method is based on the space vector approach and the relationship between CBPWM and space vector pulse width modulation (SVPWM) methods is provided. In this paper, four CBPWM methods called: sinusoidal PWM, third harmonic injection PWM, symmetrical PWM and discontinuous PWM are presented. These different CBPWM schemes are established according to the distribution of zero vectors and the switching pattern of the SVPWM method. The comparison of output voltage performance with different CBPWM schemes are investigated. Compared to the conventional method the calculation time of the proposed method is reduced around 50%. Concretely, the calculation time of the SVPWM method is 45 μs, while the calculation time of the proposed method is 22 μs. The experiments have been carried out to show the effectiveness of the proposed method.

One of the main reasons for adopting the field oriented controlled (FOC) induction machine for high performance application is its capability for easy implementation in field weakening. In a sensorless FOC induction machine, the speed estimation in Field Weakening (FW) region and the sensitivity to parameter error of the motor is a major problem. Model Reference Adaptive System (MRAS) approach is one of the best techniques to estimate the rotor speed due to its straight forward stability approach. Space vector pulse width modulated (SVM) voltage source inverter is preferred to feed the FOC induction machine rather than the traditional sinusoidal pulse width modulated (SPWM) inverter due to the full utilization of voltage and current rating of the inverter. In this paper, a sensorless FOC induction machine with MRAS scheme based on sliding mode (SM) technique to estimate the rotor speed in the FW region using SVM fed inverter is modeled. The drive system is simulated by MATLAB/Simulink and the performance of the technique is evaluated by comparing the model with FOC induction machine with sensor using SVM inverter.

Pulse width modulation (PWM) techniques involving different switching sequences are used in space vector-based PWM generation for reducing line current ripple in induction motor drives. This study proposes a hybrid PWM technique employing five switching sequences. The proposed technique is a combination of continuous PWM, discontinuous PWM (DPWM) and advanced bus clamping PWM methods. Performance of the proposed PWM technique is evaluated and compared with those of the existing techniques on a constant volts per hertz induction motor drive. In terms of total harmonic distortion in the line current, the proposed method is shown to be superior to both conventional space vector PWM (CSVPWM) and DPWM over a fundamental frequency range of 32–50 Hz at a given average switching frequency. The reduction in harmonic distortion is about 42% over CSVPWM at the rated speed of the drive.