Space Vector Control Strategy Research Articles

A novel dual power-driven electric power steering system for electric commercial vehicles

To solve the power limitation problem faced by the development of EPS system for commercial vehicles and achieve the high-performance steering, this article presents a novel dual power-driven electric power steering system (DPEPS) for commercial vehicles by using the open winding permanent magnet synchronous motor (OPMSM) fed by dual inverter with high and low DC voltage supplies. First, the two-level control strategy is introduced for the developed DPEPS system, where the upper control is designed to make the actual steering follow the expected steering performance as determined by the assistant torque curve and to generate the appropriate target current according to the vehicle speed and steering torque. And then the lower control consists of the synthetical space vector control scheme and dual PI control loop is used to execute commands from the upper control, which can make the motor execute the appropriate power supply method according to the steering torque and assist current. Finally, a co-simulation model is carried out for an electric bus, and based on which the proposed DPEPS system is validated.

Indirect Space Vector Modeling of Asynchronous Motor for High-Speed Electric Vehicle Propulsion

This paper presents a high performance squirrel-cage asynchronous motor (ASM) drive, proposed for high-speed electric vehicle (EV) propulsion. This is an indirect space vector control (IDSVC) scheme in the rotor flux frame of reference, in which the modeling is based on synchronously rotating coordinate system transformation. Space vector pulse width modulation (SVPWM) inverter fetches the controlled stator direct and quadrature axis responses from the speed and current controllers and supply necessary voltages to stator of ASM. The output voltage waveforms of SVPWM inverter are not sinusoidal in nature, which allows undesired harmonics at high frequency of operation. This due to inconsistent switching frequency. A second-order low-pass (SOLP) RLC filter with Butterworth approximation and was designed and connected in series with SVPWM inverter to grab harmonic free speed and torque profile during high speed operations. Similarly, another SOLP with a quality factor equal to 2 is designed and speed profiles of both filters are compared. The system is developed and simulated in MATLAB/SIMULINK to observe the speed and torque tracking capabilities. Simulation results show that the performance of drive under steady and dynamic states were good with Butterworth filter approximation with robust IDSVC scheme adopted over wide range speed-drive curve.

Performance Analysis of Dual Space Vector Modulation Technique-Based Quasi Z-Source Direct Matrix Converter

—This article proposes a dual space vector control strategy for quasi Z-source direct matrix converter (QZSDMC) which is made up of quasi Z-source network coupled to a matrix converter (MC). It ensures effective regulation of voltage regulation range and overpowers the voltage transfer ratio restrictions of conventional matrix converter. The QZSDMC can afford buck boost operation by observing the bidirectional operation capability and shoot through duty ratio. Also, it provides continuous input current and eliminates the need for input LC filter. First, the principle of operation of the proposed QZSDMC is presented in detail. Then, a dual space vector pulse width modulation technique for QZSDMC has been analyzed along with the distribution of shoot through time in the zero vector. The proposed topology with the control strategy has been simulated in MATLAB/SIMULINK and the simulation results are verified with the experimental results from the basic prototype machine controlled by FPGA.

Optimal Space Vector Modulation of Current-Source Converter for DC-Link Current Ripple Reduction

DC-link current ripple is one of the important factors for operating the current-source converter. In practice, the dc-link current ripple can be reduced by increasing the switching frequency or inductance. However, it may result in the higher switching losses, larger size, or higher cost. In order to deal with this problem, the inherent limitation of the conventional solution is discussed in this paper. The time-domain equation of the dc-link current is established for the first time. And then, a new space vector control strategy is proposed to reduce the ripple with no need of increasing the switching frequency or inductance. The space vector is divided into 12 sectors, where the dc-link current ripple can be effectively reduced by the optimal vector sequence. Finally, the proposed method is implemented on the TMS320F28335DSP + XC3400FPGA digital control hardware platform. The experimental results verify the effectiveness of the proposed strategy.

Comparative Analysis of Two Level VSI and Three Level Neutral Point Clamped Inverter for Torque Ripple Reduction in Induction Drive

This paper presents the comparative analysis of various level of multilevel inverter for induction motor torque ripple minimization. The neutralpoint clamped (NPC) inverter is used an adequate solution in AC drives application. The Conventional inverters compared to multilevel inverters have many limitations in high-voltage and high-power applications like poor power quality, high voltage stress, EMI/EMC issue etc. Also proposed the Space Vector neutral point clamped inverter for Torque ripple reduction in induction drive. The Simple Space vector control scheme is applied to neutral point clamped inverter by reference torque estimation. In this proposed topology offer an improved performance in the form of torque ripple reduction scheme. The Classical direct torque control of two-level VSI scheme is compared with proposed three-level NPC scheme. The main aim of this paper to provide a significant method and control scheme to obtained torque ripple reduction in induction motor Drive. The result shows the performance of neutral point clamped inverter using CB-PWM on induction drive. In this paper three levels VSI based Neutral Point Clamped (NPC) multilevel inverter fed induction motor drive is simulated, analyzed and compared with two levels VSI based NPC inverter drives. Torque of the motor is controlled by using space vector based direct torque control (DTC) method. The simulation results are carried out by using MATLAB/SIMULAINK environment.

Simulation and Analysis of PMSM Based on Space Vector Control Strategy

Permanent magnet synchronous motor (PMSM) vector control strategy is studied deeply in the paper based on the analysis of the operation principle of permanent magnet synchronous motor (PMSM). Permanent magnet synchronous motor (PMSM) speed-current double closed loop control system was built by Matlab/Simulink. The simulation results showed that the system had fast response speed, high accuracy and strong anti-interference ability and so on. It also proved that Permanent magnet synchronous motor (PMSM) vector control system had good dynamic and static performances.

An Optimized Strategy Based on Hysteresis Space Vector Control of Three-Phase VSR

In order to reduce the vast total harmonic distortion (THD) caused by hysteresis loop space vector control strategy in three-phase Voltage Source Rectifier (VSR), an optimized strategy based on fuzzy rules is proposed in the paper. In the new strategy, a current error vector threshold value was pre-set. When the actual current error value is less than the threshold, the hysteresis loop space vector control strategy will be adopted to reduce the switching frequency and loss. However, when the current error value is larger than the threshold, the optimized hysteresis loop control strategy based on fuzzy rules will be adopted to achieve the fast current tracking. Based on the new strategy, the simulation model has been established and simulated by matlab/simulink. And the results show that the optimized control strategy not only ensures the fast dynamic response with low switching frequency, but also reduces the current THD significantly. Finally, the feasibility and the superiority of the optimized strategy based on fuzzy rules have been further verified under a 1kW experiment system.

Space Vector Control Scheme of Three Level ZSI Applied to Wind Energy Systems

In this paper the Space Vector Control Scheme is implemented for a Wind Energy System using Three Level Impedance Source Inverter (ZSI). The wind energy system uses a Self Excited Induction generator (SEIG) which is the most emerging application in the field of Wind Energy Conversion System (WECS). The proposed system is modelled with a generator-side Diode Bridge Rectifier and a Stand-Alone side ZSI. This employs as a bridge between the generator and the stand-alone application. The model has been simulated through MATLAB/SIMULINK using the components for Diode Bridge, Impedance Network and Induction Motor Load and the SEIG is modelled analytically. The control strategy for the proposed topology is developed from Space Vector Modulation (SVM) and Z-source Network operation principles. The maximum power from the wind turbine generator and the power is transferred to the stand alone system is achieved by adjusting the shoot-through duty cycles of the Z-source network. The performances of the SEIG based WECS has been analysed and the results are tested.

Simulation Model of Traction Systems for CRH2 EMU Based on PSCAD/EMTDC

The high-speed railway based on electromechanical integration develops rapidly in China in recent years. In order to improve research for electrified railway, a model of AC-DC-AC electric locomotive is established using electro- magnetic transient software PSCAD/EMTDC. In this paper, a single-phase tri-level rectifier of unit power factor and its control strategy of direct transient current control method are introduced at first. And then the working principles of the voltage space vector control strategy of inverter and the vector control strategy of cage motors are analyzed. The inverter and the motors must be as a whole because of the realization of motor vector control based on SVPWM inverter. At last, a model is established and the correctness and effectiveness of the model can be verified by the corresponding theory results. The simulation model is useful for the analysis of low frequency resonance in locomotives. The results will be applied in the research of mechanics and electric coupling in high speed electrified railway.

Performance evaluation of doubly-fed twin stator induction machine drive with voltage and current space vector control schemes

The doubly-fed twin stator induction machine (DFTSIM) is of interest as an adjustable speed drive (ASD) and a variable speed generator (VSG), as it combines the advantages of a brushless drive with the potential for high-voltage, high-power, and limited speed range applications. Previous work on the DFTSIM (or its equivalent brushless doubly-fed machine) has considered steady state performance with open loop control or dynamic performance with closed loop control, but has not considered an overall peformance evaluation with an appropriate closed loop speed control. The comparative dynamic and steady state performance of a laboratory DFTSIM drive using ‘voltage space vector control’ and ‘current space vector control’ schemes is discussed. While the magnitude of the control winding voltage (or current) space vector is dynamically controlled to obtain the desired torque in a speed control loop, its position is regulated to operate the machine in synchronous mode. Results show that the maximum efficiency for the voltage space vector control is slightly higher than that for the current space vector control scheme, but the current space vector control offers better dynamic response and minimum converter voltampere requirement. Although the reduction in the converter VA rating with the DFTSIM drive is similar to that achievable with a slip power recovery drive, the brushless DFTSIM drive has a greater potential for applications requiring high reliability and low maintenance. Further, the DFTSIM is a viable alternative in the context of non-conventional power generation such as wind and small hydro.

Multiple space vector control for self-commutated power converters

This paper proposes a multiple space vector control strategy for self-commutated power converters. The strategy makes it possible to realize a significant reduction in power losses with the lowest possible switching frequency in the steady-state, continuous operation with high speed tracking of commands in the transient state and flexible controls with the utilization of degrees of freedom in the assignment of voltage vectors to the power converters. High efficiency of the strategy is confirmed by experiments in which two pulse switching mode and the speed of response in 5(ms) with one side model of the power converter terminals of self-commutated HVDC (high voltage direct current). The continuous operation is verified by simulations in a one-line ground fault. Another simulation based on the unbalanced DC voltages shows the balance control of DC voltages to be effective in HVDC transmission with self-commutated power converters connected in series on the AC and the DC sides.