A novel approach implementing AC position servo 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.

This chapter describes the sliding-mode control of permanent magnet synchronous motor (PMSM) servo systems. The typical structure of the systems consists of the position, velocity, and current control loops. The design of three controllers, position controller, speed controller, and current controller, and a filter in speed loop has been described respectively, aimed at reaching high-performances of PMSM servo systems, such as fast response, strong robustness, and high precision. The digitization of terminal sliding-mode (TSM) controllers of PMSM servo system has been discussed for the purpose of practical implementation.

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.

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.

Field programmable gate array (PFGA) has advantages of parallel processing, fast operation, and high reliability. Therefore, it has broad application prospects in high-performance servo drives. As an indispensable operation in the space vector pulse width modulation (SVPWM) algorithm for permanent magnet synchronous motor (PMSM), division is the most complex among the four operations. When implemented in FPGA, it will consume the most logic resources and generate the longest latency. According to the characteristics of the division algorithm in SVPWM, this paper proposes an improved design method for the universal divider. Through the improvement of the division design, less resource consumption and shorter latency are realized.

Permanent magnet synchronous motor (PMSM) is the most widely used motor in electric vehicles (EV) due to its high power density and high efficiency. Conventional direct torque control (DTC) is developed to improve the performance of speed response of the PMSM drive but it suffers from higher torque ripples. Therefore a space vector modulation (SVM) based DTC has been developed to enhance the speed response. Due to the use of flux comparator and torque comparator conventional DTC has disadvantages such as higher torque and current ripples at steady state. To improve the performance of PMSM drive a space vector pulse width modulation is used with 3 level NPCI. To improve the performance of 2 level inverter in the PMSM drive is replaced with a neutral point clamped inverter (NPCI). Also, the switching selection strategy of SVM is modified using nearest three space vector pulse width modulation to reduce the total harmonic distortion (THD) in the inverter output. The simulation outcome proves that the SVM technique implementation in DTC for 3 level NPCI yields good performance for PMSM.KeywordsElectric vehicles (EV),voltage source inverter (VSI)Direct torque control (DTC)Neutral point clamped inverter (NPCI)Permanent magnet synchronous motor (PMSM)Space vector modulation (SVM)Total harmonic distortion (THD)

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.

Permanent magnet synchronous motors (PMSMs) have dominated the motion control industry to the present, and, according to the current trend, there seems to be no end for it Induction motors have always been a minority in the motion control, and they are mainly used in applications, where the field weakening can be utilized to avoid the over-sizing of the drive, which would be the case with PMSMs. There is an increasing trend of using Space vector pulse width modulation (SVPWM) because of their easier digital realization and better dc bus utilization. In this paper both Sinusoidal PWM and space vector PWM feeding a PMSM motor are considered. These techniques are studied through simulation using MATLAB/SIMULENK software and the performance of both the techniques are compared. It is shown through simulation that Space vector PWM effectively utilize dc line voltage and generates reduced THD when compared with Sinusoidal PWM.

This paper presented a vector controlled drives of permanent Magnet Synchronous Motor (PMSM) by using Proportional-Integral (PI) Speed controller based dSPACE implementation. The concept of vector control is applied to PMSM to obtain linear dynamics similar to that of a DC motor. The model consist of two control loops, hysteresis current controller is used for inner loop current control and PI controller for outer loop speed control. PI speed controller selected due to simplicity compare to fuzzy, neutral etc. to make sure dSPACE DS1103 successfully implemented. The PMSM vector control algorithm for a theoretical basic has been verified by experimental results and created a rapid control prototype environment by using MATLAB/ Simulink and the DS1103 DSP of dSPACE.

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.

<div class="section abstract"><div class="htmlview paragraph">This paper presents a proposed space vector pulse width modulation (SVPWM) controller for permanent magnet synchronous motor (PMSM). The Space vector pulse width modulation controller is used for power loss, torque ripple minimization of this type of motors. The proposed controller is a newly applied of Belt starter generator (BSG). The dynamic response of the BSG with the proposed controller is studied during the starter and generator modes with desired torque and speed with the optimal I<sub>d</sub>, I<sub>q</sub> current input. The effectiveness of the proposed space vector pulse width modulation is then analyzed with Field oriented control (FOC) characteristics in the BSG operating system. The analysis results are presented to demonstrate the characteristics and effectiveness of the proposed control techniques.</div></div>

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.

The dc bus current sampling technology with the traditional space vector pulsewidth modulation (SVPWM) scheme imposes several challenges, particularly at the low-modulation region and sector boundaries, where the duration of a nonzero vector may be so short that the phase current cannot be measured reliably. A new dc bus current sensed SVPWM (SSVPWM) method is proposed, in this article, to overcome shortcomings of the traditional algorithm. By introducing the concept of minimum sampling time, the unobservable area of the dc bus sampling system is divided accurately. Then, the SSVPWM and associated current reconstruction strategy are proposed by inserting the measurement vector and the compensation vector. Finally, experiments were performed on a 2.7-kW permanent magnet synchronous motor (PMSM), and the experimental results showed that the current sampling error of the proposed SSVPWM is less than 2% and the THD of three-phase current is less than 4.9%, which provides accurate current feedback for high-performance vector control.

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.

Permanent magnet synchronous motor (PMSM) servo system requires a high dynamic performance of speed. The control object of speed loop, which can be described using a two-order transfer function, is the PMSM regulated by current loop. PI controller is generally used in speed control, in which the performance improvement is limited by the strong coupling and nonlinearity of the system. In this paper, an adaptive model following speed controller (AMFC) with state feedback control and model following methods is designed based on the Popov hyperstability theory and modeled in the MATLAB. The simulation results show that, compared with PI control, AMFC raises the speed loop dynamic performance of PMSM by compensating the influence of coupling and nonlinearity, so it is more suitable for servo system.