共查询到20条相似文献,搜索用时 46 毫秒
1.
Griva G. Habetler T.G. Profumo F. Pastorelli M. 《Power Electronics, IEEE Transactions on》1995,10(4):464-471
This paper investigates the operation of a direct torque controlled drive when operating under transient conditions and when operating in overmodulation conditions or in the “transition region” to six-step operation. The direct torque control is a dead-beat control of the torque and flux magnitude. In the steady-state, the stator voltage vector which drives the torque and flux to the reference value is calculated during each fixed switching period. Under transient or overmodulation conditions, an alternative switching algorithm must be used since dead-beat control is no longer possible. Two alternatives are presented for operation in overmodulation. The first involves a determination of the switching state a priori, and calculating the duty cycle for each phase based on the torque and flux error. A much simpler scheme is presented which utilizes the voltage reference vector from the direct torque control algorithm. This scheme, although not resulting in dead-beat control, is shown to provide very satisfactory performance in overmodulation. The direct torque control method shows great promise for light traction applications where a large quasi-constant power region is required. The scheme operates very satisfactorily in overmodulation, compared with existing current regulated PWM-based schemes, due to the fact that the voltage space vectors are directly controlled. A complete experimental evaluation of the proposed scheme operating in the transition region is also given 相似文献
2.
Bojoi R.I. Griva G. Bostan V. Guerriero M. Farina F. Profumo F. 《Power Electronics, IEEE Transactions on》2005,20(6):1402-1412
In this paper, a current control scheme, based on proportional-integral regulators using sinusoidal signal integrators (SSIs), is proposed for shunt type power conditioners. The aim is to simplify the implementation of SSI-based current harmonic compensation for industrial implementations where strict limitations on the harmonic distortion of the mains' currents are required. To compensate current harmonics, the SSIs are implemented to operate both on positive and negative sequence signals. One regulator, for the fundamental current component, is implemented in the stationary reference frame. The other regulators, for the current harmonics, are all implemented in a synchronous reference frame rotating at the fundamental frequency. This allows the simultaneous compensation of two current harmonics with just one regulator, yielding a significant reduction of the computational effort compared with other current control methods employing sinusoidal signal integrators implemented in stationary reference frame. A simple and robust voltage filter is also proposed by the authors to obtain a smooth and accurate position estimation of the voltage vector at the point of common coupling (PCC) under distorted mains' voltages. The whole control algorithm has been implemented on a 16-b, fixed-point digital signal processor (DSP) platform controlling a 20-kVA power conditioner prototype. The experimental results presented in this paper for inductive and capacitive loads show the validity of the proposed solutions. 相似文献
3.
Overmodulation strategy for high-performance torque control 总被引:1,自引:0,他引:1
Jul-Ki Seok Joohn-Sheok Kim Seung-Ki Sul 《Power Electronics, IEEE Transactions on》1998,13(4):786-792
In the overmodulation region, the operation of the electrical drive system with a current controller is characterized by a rapid deterioration of motor torque and speed. It is desirable to use the overmodulation strategy, which guarantees the fast response even in transient state and satisfies the overall closed-loop control performance. In this paper, in order to improve the dynamic characteristics of the electrical drive, a new overmodulation technique is proposed. Considering the current transition characteristics, an efficient overmodulation strategy is introduced to achieve better transient performance through an adequate voltage selection. With the help of a new overmodulation strategy, required electrical torque can be directly produced as quickly as possible, and stable drive characteristics can be achieved in the transient condition. The proposed method has been implemented on an actual inverter system and thoroughly tested on a 900-W interior permanent magnet synchronous machine (IPMSM) to confirm its feasibility 相似文献
4.
Full Utilization of the Inverter in Split-Phase Drives by Means of a Dual Three-Phase Space Vector Classification Algorithm 总被引:2,自引:0,他引:2
《Industrial Electronics, IEEE Transactions on》2009,56(1):120-129
A simple and effective space vector pulsewidth-modulation technique for six-phase voltage-source-inverter-fed split-phase induction motors is presented in this paper. The approach employs dual three-phase space vector modulators equipped with overmodulation schemes that compensate for the voltage gain reduction due to the use of two independently controlled three-phase inverters. It secures full control of the voltage gain up to the maximum achievable gain with negligible low-order harmonics and utilizes a simple classification algorithm for the implementation of the space vector modulation (SVM) in both linear and overmodulation modes. Experimental results are provided to verify the validity of the proposed SVM split-phase approach. 相似文献
5.
6.
Bor-Ren Lin Yi-Lang Hou 《Industrial Electronics, IEEE Transactions on》2002,49(1):173-185
A control scheme of an integrated power quality compensator, which employs an active rectifier to work simultaneously as an active power filter (APF) to decrease current harmonics, is proposed. The employed rectifier is based on a capacitor-clamped configuration to produce multilevel pulsewidth modulation waveforms which result in low voltage stress and low conduction loss on the power switches. The proposed active rectifier is controlled to track the supply current to be a sinusoidal wave with low current harmonics. The advantages of the proposed control scheme are high power factor, low current harmonics, no complicated calculations for current harmonics elimination, and no dedicated APF needed for harmonic elimination. The experimental results are used to verify the validity and effectiveness of the proposed control scheme 相似文献
7.
Chatterjee K. Fernandes B.G. Dubey G.K. 《Industrial Electronics, IEEE Transactions on》2000,47(3):542-548
A high-power low-distortion static VAr compensator based on a synchronous link converter has been proposed, where the harmonics are eliminated by incorporating a low-power insulated-gate-bipolar-transistor-based controlled current auxiliary converter in conjunction with a high-power gate-turn-off-thyristor-based converter. In this paper, a new load compensator based on this topology is proposed which does not require the information of the voltampere required by the load. As the requirement of the reactive voltampere calculator is eliminated, the scheme becomes insensitive to system frequency variations, temperature, and component aging. The control scheme required for the compensator is developed. The operation of the scheme is validated through extensive simulation studies. Experimental results obtained from a laboratory prototype are provided to demonstrate the viability of the scheme 相似文献
8.
Shrivastava Y. Sathiakumar S. Hui S.Y. 《Power Electronics, IEEE Transactions on》1998,13(6):1038-1045
The authors present a statistical approach to the analysis of random pulsewidth modulation (RPWM) methods which generate PWM signals by comparing a reference modulating function with random numbers or signals. Such an approach is used to analyze and optimize a new weighted RPWM (WRPWM) method and also a standard trapezoidal RPWM method. The WRPWM scheme combines the advantages of the nondeterministic and deterministic PWM methods by adding some deterministic nature into the nondeterministic RPWM method. Both theoretical and experimental results confirm that the optimized WRPWM method has better spectral performance over the standard RPWM schemes and has attractive features such as the potential of third-harmonic boosting, reduced acoustic noise, and minimal low-order harmonics under an overmodulation condition for electronic drive applications 相似文献
9.
Jung-Min Kwon 《International Journal of Electronics》2013,100(3):419-433
This paper discusses and analyses a simple on-line compensation scheme for dead-time and inverter nonlinearity in the pulse width modulated (PWM) voltage source inverter (VSI). Dead-time effect and voltage drop in switching devices cause nonlinearity between reference and output voltage. In a conventional three-phase six-switch inverter, this nonideal condition adds extraneous harmonics that badly disturb voltage characteristics. In its turn, voltage disturbance causes distortion of the current waveform and degrades performance. In this paper, an on-line dead-time compensation method based on inverse dynamics control is proposed, and it is much simpler than conventional full/reduced order observation methods adopted in dead-time compensation. Disturbance voltages are observed on-line with no additional circuitry or off-line measurements. The observed disturbance voltages are fed back to the voltage reference for compensation. Stability problem of the proposed observer arisen from inverter delay and parameter mismatch was analysed. The proposed method is applied to a surface-mounted permanent-magnet synchronous motor (SPMSM) drive. The effectiveness of the proposed scheme is validated by the experimental results. 相似文献
10.
HongZhe Jin JangMyung Lee 《Industrial Electronics, IEEE Transactions on》2009,56(1):169-177
A new robust model reference adaptive control (RMRAC) scheme for the current regulation of a permanent-magnet synchronous motor (PMSM) is proposed in a synchronous frame, which is completely free from the control performance degradation caused by parameter uncertainties. The current regulator of the PMSM is the innermost loop of its electromechanical driving system and plays an important role in the control hierarchy. When the PMSM runs precisely at high speeds, the cross-coupling terms must be compensated for. In the proposed RMRAC, the input signal is composed of the control voltage obtained by the model reference adaptive control (MRAC) law and the output of the disturbance estimator. The gains of the feedforward and feedback controllers are estimated by the proposed modified gradient method, where the system disturbances are filtered out by the estimated current regulation error. A voltage corresponding to the estimated system disturbances is fed forward to the control input in order to filter out the disturbances. The proposed method compensates the cross-coupling terms in a synchronous current model regardless of parameter variations. It also shows a good real-time performance due to the simplicity of control structure. Through simulations and real experiments, the efficiency of the proposed method is verified. 相似文献
11.
Sung-Chan Ahn Dong-Seok Hyun 《Power Electronics, IEEE Transactions on》2002,17(5):616-622
In general, three-phase PWM AC/DC power converters have been implemented in the synchronous frame model to eliminate steady state errors effectively and to obtain fast transient response characteristics. However, controllers designed in such way would have input current harmonics and DC-link voltage ripples under the unbalanced input voltage conditions due to the assumption of the balanced input voltage conditions. This paper describes a new control scheme to minimize harmonic distortions of the input current and DC-link voltage in the converter under the unbalanced input voltage. conditions. The synchronous frame input voltage, which is considered as the input side back-EMF component, is regulated pertinently according to the input voltage conditions. The current command is selected to eliminate the reactive power and the second order harmonic component of active power. In this case, the analysis of the input voltage is implemented in the synchronous frame without detecting the phase angle and magnitude of each phase voltage. The proposed control scheme is simple and effectively minimizing the harmonic distortions in the input and output system under the unbalanced input voltage conditions. 相似文献
12.
A Method for Extracting the Fundamental-Frequency Positive-Sequence Voltage Vector Based on Simple Mathematical Transformations 总被引:1,自引:0,他引:1
de Souza H.E.P. Bradaschia F. Neves F.A.S. Cavalcanti M.C. Azevedo G.M.S. de Arruda J.P. 《Industrial Electronics, IEEE Transactions on》2009,56(5):1539-1547
In this paper, a novel scheme for obtaining the fundamental-frequency positive-sequence grid voltage is proposed. The method is based on four simple mathematical transformations; two of them are in the stationary reference frame, which are able to eliminate odd harmonics from the original signals. The other two transformations are implemented in a synchronously rotating reference frame in order to eliminate even harmonics. The output of the last transformation block is the input to a synchronous reference-frame phase-locked loop for detecting the frequency and position of the positive-sequence voltage vector. The proposed algorithm was verified through simulations and experiments by applying distorted and unbalanced signals, containing positive and negative-sequence components. The results are in agreement with those theoretically predicted and indicate that the proposed scheme has a great potential for use in grid-connected converter synchronization algorithms. 相似文献
13.
A General Space Vector PWM Algorithm for Multilevel Inverters, Including Operation in Overmodulation Range 总被引:2,自引:0,他引:2
This paper proposes a simple space vector pulsewidth modulation algorithm for a multilevel inverter for operation in the overmodulation range. The proposed scheme easily determines the location of the reference vector and calculates on-times. It uses a simple mapping to generate gating signals for the inverter. A five-level cascaded inverter is used to explain the scheme. The scheme can be easily extended to a n-level inverter. It is applicable to neutral point clamped topology as well. Experimental results are provided for five-level and seven-level cascaded inverters 相似文献
14.
Bor-Ren Lin Shuh-Chuan Tsay Mu-Shan Liao 《International Journal of Electronics》2013,100(11):1189-1204
A simple strategy and low cost control for the switching mode rectifier to work simultaneously as a power factor corrector and an active power filter (APF) to reduce current harmonics drawn from the nonlinear load are analysed and presented in this paper. The principal component of the control circuit is an Intel 80196MC microcontroller that performs the dc bus voltage and line current control. The sliding mode control is used in the current loop to achieve fast line current dynamics. The source currents only are measured in the proposed control scheme instead of both the source and load currents needed in the conventional control approach. A simple proportional-integral control is adopted in the voltage loop to achieve slow dc bus dynamics. The proposed control strategy can achieve a high power factor and low current harmonics. No dedicated APF is needed in the proposed control strategy. To demonstrate the effectiveness of the integrated power factor compensator for elimination of reactive power and current harmonics, software simulation and hardware tests are performed. 相似文献
15.
Yasser Abdel-Rady Ibrahim Mohamed 《Industrial Electronics, IEEE Transactions on》2007,54(5):2491-2499
This paper describes a novel instantaneous torque control scheme for a high-performance direct-drive permanent-magnet synchronous motor. The scheme consists of a robust adaptive instantaneous torque observer and a hybrid-type variable-structure instantaneous torque controller. First, to robustly obtain the instantaneous electromagnetic torque information, a robust adaptive torque observer is designed by considering all possible current model uncertainties. The observation gains and uncertainties prediction rules are derived in the sense of Lyapunov theory so that the stability of the proposed estimation scheme is fulfilled. Second, to ensure perfect tracking of the output torque and providing means in eliminating torque ripples, the frequency modes of the disturbances to be eliminated should be included in the stable closed-loop system. To achieve this objective, a hybrid-type variable-structure controller with internal model, for the flux harmonics and system uncertainties, is adopted. The hybrid controller shows better disturbance rejection without control chattering. Comparative evaluation results are presented to demonstrate the validity and effectiveness of the proposed instantaneous torque control scheme. 相似文献
16.
This paper proposes a novel rotor resistance identification method for an indirect rotor flux-orientated controlled induction machine drive. The method is effectively integrated with the intermediate current control loop of the system. A decoupled synchronous voltage control scheme is used to achieve a fast, accurate current control response and indicates the relative thermal change of the rotor resistance. A model reference adaptive control scheme is then used to track the variation of the rotor resistance. Other issues, such as the nonideal characteristics of the power devices, stator resistance variation and comparison with two other parameter identification methods, are included. This method is less complex and more effective than others, and this is supported by theoretical analysis, and verified by simulation and experimental results 相似文献
17.
Kyeong-Hwa Kim 《International Journal of Electronics》2013,100(8):481-494
A model reference adaptive control (MRAC)-based nonlinear speed control strategy of an interior permanent magnet (IPM) synchronous motor with an improved maximum torque operation is presented. In most servo systems, the controller is designed under the assumption that the electrical dynamics are neglected by the field-oriented control. This requires a high-performance inner-loop current control strategy. However, the separate designs for a high-performance current regulator and a robust speed controller need considerable effort. To overcome this limitation, an MRAC-based nonlinear speed control strategy for the IPM synchronous motor is presented, considering the whole nonlinear dynamics. Nonlinear speed control is achieved by an input–output linearization scheme. This scheme, however, gives an unsatisfactory performance under the mismatch of the system parameters and load conditions. For the robust output response, the controller parameters are estimated by an MRAC technique in which the disturbance torque and flux linkage are estimated. The adaptation laws are derived from Lyapunov stability theory. In view of the drive efficiency, the motor has to provide the maximum torque for a given input. To drive the IPM synchronous motor under improved maximum torque operation, the estimated flux linkage is employed for the generation of the d-axis current command. The robustness and output performance of the proposed control scheme are verified through simulation results. 相似文献
18.
A control scheme is proposed that employs an active rectifier to work simultaneously as an active power filter to decrease current harmonics. The adopted capacitor clamped rectifier is controlled to draw a sine wave line current with low current harmonics. A voltage controller, three capacitor voltage compensators and one current controller are used in the proposed control algorithm to achieve a constant DC bus voltage, balanced capacitor voltages and line current tracking. The validity of the proposed system is proved by the results of computer simulations and experimental tests. 相似文献
19.
A simple and robust digital current control technique of a permanent magnet (PM) synchronous motor using a time delay control approach is presented. Among the various current control schemes for a voltage source inverter-fed PM synchronous motor drive, the predictive control is known to give a superior performance. This control technique, however, requires the full knowledge of machine parameters and operating conditions, and gives an unsatisfactory response under the parameter mismatch between the motor and controller. To overcome such a limitation, the disturbances caused by the parameter variations are estimated by using a time delay control approach and used for the computation of the reference voltages by a simple feedforward control. Thus, the steady-state control performance can be significantly improved in an extremely simple manner, while retaining the good characteristics of the predictive control such as the good transient response and stable inverter operation. The proposed control scheme is implemented on a PM synchronous motor using the software of DSP TMS320C30 and the effectiveness is verified through the comparative simulations and experiments 相似文献
20.
Ben-Sheng Chen Yuan-Yih Hsu 《Industrial Electronics, IEEE Transactions on》2008,55(2):655-664
In this paper, a novel controller with fixed modulation index (MI) and variable dc capacitor voltage reference to minimize voltage and current harmonics is presented for a distribution static synchronous compensator (STATCOM). The STATCOM with the proposed controller consists of a three-phase voltage-sourced inverter and a dc capacitor and is used to provide reactive power compensation and regulate ac system bus voltage with minimum harmonics. A systematic design procedure based on pole-zero cancellation, root locus method, and pole assignment method has been developed to determine proper parameters for the current regulator, the dc voltage controller, and the ac voltage controller of the STATCOM. With the proposed STATCOM controller, harmonic distortions in the inverter output current and voltage can be reduced since the MI is held constant at unity in steady state. In addition, a fast adjustment in the STATCOM output reactive power is achieved to regulate the ac bus voltage through the adjustment of the dc voltage reference during the transient period. Simulation and experimental results for the steady-state operating condition and transient operating conditions for the system subjected to a reactive current reference step change, a three-phase line to neutral fault, and a step load change are presented to demonstrate the effectiveness of the proposed controller. 相似文献