Research on an Improved Three-Level SVPWM Modulation Algorithm Based on ID-NPC Topology

The Space Vector Pulse Width Modulation (SVPWM) is possibly the best among all the PWM techniques for variable frequency drive applications. Unfortunately, the modulation algorithm is mainly implemented with software based on microcontroller or digital signal processors (DSP). These are software-based technique purely and obviously not an ideal solution. Employing Field Programmable Gate Array (FPGA) to realize SVPWM strategies provides advantages that it is considered as an appropriate solution to boost system performance of an SVPWM algorithm. Moreover, although in the literatures the implementation for three-phase SVPWM based on FPGA is not lacking, however all these designs are based on the conventional SVPWM without considering hardware-resource saving and not simple. This paper present a simple realization of 5-segment discontinuous SVPWM with a difference approach based on FPGA, in which the judging of sectors and the calculation of the firing time to generate the SVPWM waveform is simple, and also the switching losses is low. The proposed discontinuous SVPWM has been designed and successfully implemented by using APEX20KE Altera FPGA considering hardware-resource saving and has successfully driven a three phase inverter system with induction machine 1.5 kW as load.

A new instantaneous torque-control strategy is presented for high-performance control of a permanent magnet (PM) synchronous motor. In order to deal with the torque pulsating problem of a PM synchronous motor in a low-speed region, new torque estimation and control techniques are proposed. The linkage flux of a PM synchronous motor is estimated using a model reference adaptive system technique, and the developed torque is instantaneously controlled by the proposed torque controller combining a variable structure control (VSC) with a space-vector pulse-width modulation (PWM). The proposed control provides the advantage of reducing the torque pulsation caused by the nonsinusoidal flux distribution. This control strategy is applied to the high-torque PM synchronous motor drive system for direct-drive applications and implemented by using a software of the digital signal processor (DSP) TMS320C30. The simulations and experiments are carried out for this system, and the results demonstrate the effectiveness of the proposed control.

In order to solve the problem that the third harmonic current of Five phase Permanent Magnet Synchronous Motor (FPMSM) cannot be closed-loop controlled in the single-plane vector control of the five-phase permanent magnet synchronous motor, the two-plane vector Space Vector Pulse Width Modulation algorithm (SVPWM) algorithm is studied in this paper. The first to establish the mathematical model of dual dq plane, expand Park &#x0026; Clark transformation, changed the traditional SVPWM, the asymmetry problem of the double dq plane treated by the normalization method. The SVPWM control is simplified, then set i<inf>q3</inf> = ki<inf>q1</inf> and the Speed&#x0026;Current double closed-loop experiment is conducted to verify the correctness of the algorithm. Finally, through the Fast Fourier Transform (FFT) of the output current, amplitude and effective value of the current after the injection of the thirdharmonic are within the allowable range, the output torque pulsation is stable, it constitutes the dual dq plane drive control system of FPMSM.

The development of electric and hybrid vehicles has gained increasing attention in recent years. This paper proposes an Electric drive for Hybrid vehicles application and its control strategy to achieve a wide speed range. In these vehicles, important requirements for the electric drive are low weight, small volume, high efficiency and low cost. When choosing the motor for the vehicle drive, the induction motor is an obvious alternative but a permanent magnet synchronous motor (PMSM) can offer advantages in terms of higher efficiency and specific power. In this paper a permanent magnet synchronous machine (PMSM) is used as an electric drive machine. The operation of a PMSM above the base speed is possible by weakening the permanent-magnet excitation by a demagnetizing field component supplied by the stator winding. This can be done by closed loop operation of PMSM. The speed and torque control of the PMSM drive used as hybrid vehicle is controlled by proper tuning the PI controllers. A three level diode clamped inverter using IGBT's has simulated, whose switching sequences are controlled by Space Vector Pulse Width Modulation (SVPWM). A mathematical model of PMSM drive suitable for hybrid vehicle has simulated and proper closed loop control is established by field oriented control method. The entire work is done in MATLAB/SIMULINK.

The direct torque control theory has achieved great success in the control of permanent magnet synchronous motor. A Direct Torque Control (DTC) scheme of Permanent Magnet Synchronous Motor (PMSM) is presented. Based on in-depth analysis of PMSM mathematical model in abc frame and  frame are established and the operation principle of DTC-SVPWM system, the relationships between the torque and fundamental components. A novel space vector pulse width modulation (SVPWM) method which has a feature of low harmonic is proposed. The proposed method is adopted to implement the direct torque control (DTC) of a three-phase PMSM. A large number of simulation results show that the DTC System of PMSM has fast response and good dynamic performance. Aiming at the direct torque control in PMSM Drives, in this paper explained the theoretical basis of the direct torque control (DTC) for PMSM firstly. Then explained the difference between the applications of DTC-SVPWM to PMSM. Finally the MATLAB/Simulink models were developed to examine the DTC- SVPWM for PMSM. The simulation results is presented in this paper.

In order to improve the Direct Current (DC) bus utilization ratio and realize harmonic suppression of a five-phase induction motor, the SVPWM (Space Vector Pulse Width Modulation) algorithm was researched in depth. Based on an analysis of the present SVPWM algorithm and the volt-second balance principle, a dynamic and adjustable new pattern four-vector SVPWM algorithm was proposed. The algorithm uses the modulation index and zero vector to improve the characteristics of the inductor motor, the function relationship with real-time dynamic ratio between the action–time ratio of the space voltage vector and the modulation index was proposed to maximize DC bus utilization ratio, and the random zero-vector dynamic modulation mode was used to reduce harmonic influence, being able to spread harmonics concentrated around certain frequencies across a wider frequency band and thus produce a more continuous and uniform power spectrum. The new algorithm model was built using Matlab/Simulink, and the simulation and experimental results demonstrated that the algorithm is effective and feasible.

Permanent magnet synchronous motor (PMSM) now is widely used in hybrid vehicle drive area. When the space vector pulse width modulation (SVPWM) is used in PMSM control, the stator three phase currents must be collected for its control calculation. In this paper, a PMSM stator current collection system based on C8051F500 and AD7865 is designed, and proved to be effective with experiments.

Conventional Space Vector Pulse Width Modulation (CSVPWM) uses conventional switching sequence in which near about 15 percent increment can be obtained in voltages compared to Sine Pulse Width Modulation (SPWM). But this method can be further modified into other advanced bus clamping methods called as Bus Clamping Pulse Width Modulation (BCPWM). One of those bus clamping methods is 30-Degree Split Clamp PWM method. It has all the advantages of Conventional Space Vector Pulse Width Modulation (CSVPWM) and it eliminates some disadvantages of traditional technique. In CSVPWM there are only 6 sectors and in 30Degree Split Clamping PWM these 6 sectors are further divided into sub-sectors (12) which allows for a new switching pattern. One of the major disadvantages of 3 phase CSVPWM is that the lower order harmonics of voltages and currents are comparably higher with respect to 30-Degree Split Clamp PWM. Filters can be easily designed for 30-Degree Split Clamp PWM. Even the switching losses are high in case of CSVPWM as switching occurs when the current is maximum depending on the power factor.

This paper investigates the design and validation of a new space vector pulse width modulation (SVPWM) algorithm for thermal protection of T-type three-level inverters. Thermal overheating is the main cause of shortened-lifetime and open-circuit faults of power devices. Power devices are subjected to thermal overheating due to degradation of power devices due to continuous overloading and power cycling, and degradation and faults in cooling systems. When a thermal overheating is detected in one of the switching devices, the proposed algorithm is applied to protect the thermally-overheated switch from being short/open-circuited and hence preventing the total system from malfunction. The lifetime and the reliability of the inverter have been enhanced considerably by a simple modification of the conventional SVPWM algorithm and without adding any additional hardware or complex calculations. In addition to that, the proposed algorithm does not deteriorate the inverter's output current. The proposed thermal protection SVPWM algorithm has been designed, simulated, and experimentally validated at different operating conditions.

High-frequency signal injection methods have been widely used in sensorless control of permanent-magnet synchronous motor (PMSM) drives. However, the acoustic noise and torque ripples caused by the injected high-frequency signal limit the application of the methods. To avoid these drawbacks, this paper proposes a position estimation method that combines derivative calculations of current and zero-voltage-vector (ZVV) injection, which is especially effective for zero- and low-speed operation of sensorless PMSM drives. This investigation mainly focuses on the extraction of rotor position from ZVV period and the improvements of the accuracy of estimated position. The PMSM equation is developed in the stationary frame when ZVV is applied. The proposed d-axis current allocation scheme ensures the application of the proposed method from no load to rated load. A modified space vector pulse width modulation (SVPWM) control strategy and a ZVV extension scheme are employed to improve the accuracy of estimated position, which also makes the method more realizable. Further, a novel current sampling method that selects two suitable phase currents for derivative calculation according to the voltage sector location is proposed, which can help reduce current derivative ripples and decrease position estimation errors. Finally, the effectiveness of the proposed position estimation strategy is verified on a 1.0-kW interior PMSM (IPMSM) drive platform.

In this paper, a new model for a PMSM (permanent magnet synchronous motor) driver is proposed. The proposed model is envisioned as a better modulating drive current waveform. In the proposed system the modulating drive motor current waveform is more similar to ideal sinusoidal waveform. Advanced IGBTs and snubber circuits can be employed in the design of the driver to obtain high performance with a simultaneous reduction in THD (total harmonic distortion) and torque ripple of the motor. The proposed concept offers a significant decreasing for driver harmonics compared to classical SVPWM used. The inverter can be operated in 3-phase and 20 kHz switching frequency. A PMSM motor is operated at 3kW and 48V with the proposed model is evaluated via simulation with a corresponding SVPWM (space vector pulse width modulation) method. Results of torque ripple and THD of the motor currents on the model are discussed.

Based on the equation of small pure electric vehicle (PEV) and the mathematic model of permanent magnet synchronous motor (PMSM), synchronous motor (PMSM), the dynamic model is presented for small PEV driven by PMSM. With space vector pulse width modulation (SVPWM) algorithm, a velocity and current double closed-loop simu- lation model of PMSM control system is build in Matlab7.6/Simulink environment. Simulation results show that: the sys- tem has the advantages of fast response, high precision, strong anti-interference ability, and this novel method offers a new thought way for designing and debugging driving system of PEV.

The main drawbacks of traditional finite set model predictive control are high computational load, large torque ripple, and variable switching frequency. A less complex deadbeat (DB) model predictive current control (MPCC) with improved space vector pulse-width modulation (SVPWM) under a single-phase open-circuit fault is proposed. The proposed method predicts the reference voltage vector in the α-β subspace by employing the deadbeat control principle on the machine predictive model; thus, the exhaustive exploration procedure is avoided to relieve the computational load. To perform the constant switching frequency operation and achieve better steady-state performance, a modified SVPWM strategy is developed with the same conventional structure, which modulates the reference voltage vector. This new approach is based on a redesigned and adjusted post-fault virtual voltage vector space distribution that eliminates the y-axis harmonic components in the x-y subspace and ensures the generation of symmetrical PWM pulses. Meanwhile, the combined merits of the DB, MPCC, and SVPWM methods are realized. To verify the effectiveness of the proposed control scheme, comparative experiments are performed on a five-phase permanent magnet synchronous motor (PMSM) drive system.

One of the popular AC motor drive available in drive industry is permanent magnet synchronous motor (PMSM) drive. A novel approach of PMSM drive control using space vector pulse width modulation (SVPWM) technique is proposed based on the principle of field oriented control (vector control). In MATLAB / Simulink platform the whole system is implemented in which two control loops are used-inner current loop and outer speed loop. Beside continuous-time control, digital control using shift operator and delta operator is also presented. It is shown that the delta operator control scheme provides a unified frame-work and converges to the continuous-time control at high sampling frequency. However, the shift operator based control scheme does not leads to satisfactory result as the sampling speed increases. Simulation results verified the above facts.

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