scholarly journals Model predictive control of high power current-source converter for medium-voltage induction motor drive

2021 ◽  
Author(s):  
Hang Gao
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
High Power ◽  
Current Source ◽  
Dynamic Responses ◽  
Motor Drive ◽  
Switching Frequency ◽  
Medium Voltage ◽  
Pattern Control ◽  
Motor Drive System

As a crucial player in medium-voltage (MV) applications, high power current-source converters (CSCs) feature some distinct advantages in contrast to their voltage-source counterparts. However, the traditional control techniques, based on linear proportional-integral (PI) regulators and low band-width modulation, impose several technical issues during low switching frequency operation. In order to meet more and more stringent performance requirements on industrial drives, various high performance finite control-set model predictive control (FCS-MPC) schemes are proposed in this thesis to control CSCs employed in MV induction motor (IM) drives. The continuous-time and discrete-time dynamic models of high power CSC-fed MV IM drive are deduced, which are used to predict the evolution of state variables in the system. Issues related to MPC approach, such as prediction horizon, weighting factor selection, control delay compensation, accurate extrapolation of references, and nature of variable switching frequency are addressed as well. Model predictive power factor control (MPPFC) is proposed to accurately regulate the line power factor of CSR under various operating conditions. Meanwhile, an active damping function is incorporated into MPPFC to suppress the possible line-side LC resonance. Moreover, an online capacitance estimation method is designed in consideration on the perturbation of the filter parameters of CSR. In order to keep fixed switching frequency of CSC and improve its dynamic responses, model predictive switching pattern control (MPSPC) and model predictive space vector pattern control (MPSVPC) are proposed, in which MPC technique is combined with selective harmonic elimination (SHE) modulation and space vector modulation (SVM), respectively. In steady state, the PWM waveform of CSC follows the pattern of traditional modulation schemes, whereas during transients CSC is governed by MPC approach for the purpose on dynamic performance improvement. A common-mode voltage (CMV) reduced model predictive control (RCMV-MPC) is studied, with which the peak value of CMV in high power CSC-fed MV IM drive can be further reduced in comparison with the traditional RCMV modulation schemes. The dynamic responses of the motor drive system are further improved as well. The simulation on a megawatt motor drive system and experimental results on a low power prototype, validate the effectiveness of the proposed various control schemes.

scholarly journals Model predictive control of high power current-source converter for medium-voltage induction motor drive

2021 ◽  
Author(s):  
Hang Gao
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
High Power ◽  
Current Source ◽  
Dynamic Responses ◽  
Motor Drive ◽  
Switching Frequency ◽  
Medium Voltage ◽  
Pattern Control ◽  
Motor Drive System

As a crucial player in medium-voltage (MV) applications, high power current-source converters (CSCs) feature some distinct advantages in contrast to their voltage-source counterparts. However, the traditional control techniques, based on linear proportional-integral (PI) regulators and low band-width modulation, impose several technical issues during low switching frequency operation. In order to meet more and more stringent performance requirements on industrial drives, various high performance finite control-set model predictive control (FCS-MPC) schemes are proposed in this thesis to control CSCs employed in MV induction motor (IM) drives. The continuous-time and discrete-time dynamic models of high power CSC-fed MV IM drive are deduced, which are used to predict the evolution of state variables in the system. Issues related to MPC approach, such as prediction horizon, weighting factor selection, control delay compensation, accurate extrapolation of references, and nature of variable switching frequency are addressed as well. Model predictive power factor control (MPPFC) is proposed to accurately regulate the line power factor of CSR under various operating conditions. Meanwhile, an active damping function is incorporated into MPPFC to suppress the possible line-side LC resonance. Moreover, an online capacitance estimation method is designed in consideration on the perturbation of the filter parameters of CSR. In order to keep fixed switching frequency of CSC and improve its dynamic responses, model predictive switching pattern control (MPSPC) and model predictive space vector pattern control (MPSVPC) are proposed, in which MPC technique is combined with selective harmonic elimination (SHE) modulation and space vector modulation (SVM), respectively. In steady state, the PWM waveform of CSC follows the pattern of traditional modulation schemes, whereas during transients CSC is governed by MPC approach for the purpose on dynamic performance improvement. A common-mode voltage (CMV) reduced model predictive control (RCMV-MPC) is studied, with which the peak value of CMV in high power CSC-fed MV IM drive can be further reduced in comparison with the traditional RCMV modulation schemes. The dynamic responses of the motor drive system are further improved as well. The simulation on a megawatt motor drive system and experimental results on a low power prototype, validate the effectiveness of the proposed various control schemes.

scholarly journals Very Low Sampling Frequency Model Predictive Control for Power Converters in the Medium and High-Power Range Applications

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 199
Author(s):  
Jaime A. Rohten ◽  
Javier E. Muñoz ◽  
Esteban S. Pulido ◽  
José J. Silva ◽  
Felipe A. Villarroel ◽  
...  
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
High Power ◽  
Sampling Frequency ◽  
Power Converter ◽  
Switching Frequency ◽  
Nonlinear Feedback ◽  
Space Vector ◽  
Frequency Model ◽  
Linear And Nonlinear

Several control strategies have been proposed with the aim to get a desired behavior in the power converter variables. The most employed control techniques are linear control, nonlinear control based on linear and nonlinear feedback, and predictive control. The controllers associated with linear and nonlinear algorithms usually have a fixed switching frequency, featuring a defined spectrum given by the pulse width modulation (PWM) or space vector modulation (SVM) time period. On the other hand, finite set model predictive control (FS-MPC) is known to present a variable switching frequency that results too high for high power applications, increasing losses, reducing the switches lifetime and, therefore, limiting its application. This paper proposes a predictive control approach using a very low sampling frequency, allowing the use of predictive control in high power applications. The proposed method is straightforward to understand, is simple to implement, and can be computed with off-the-shelf digital systems. The main advantage of the proposed control algorithm comes from the combination of the model predictive control and the SVM technique, drawing the principal benefits of both methods. The provided experimental results are satisfactory, displaying the nature of space vector-based schemes but at the same time the fast response as expected in predictive control.

scholarly journals Sensorless Current Source-Fed PM Drive System For Low Speed Operations

2021 ◽  
Author(s):  
Ehsan Al-Nabi
Keyword(s):  
Permanent Magnet ◽  
High Power ◽  
Permanent Magnet Synchronous Motor ◽  
Current Source ◽  
Drive System ◽  
Switching Frequency ◽  
Low Speed ◽  
Pulse Width Modulated ◽  
Medium Voltage ◽  
Current Source Converter

In this thesis, a sensorless method for low and zero speed operation is proposed for a high-power medium-voltage pulse-width-modulated Current–Source-Converter (CSC)-fed Interior Permanent Magnet Motor (IPM) drive system. The proposed method is based on injection of a high-frequency (HF) pulsating sinusoidal signal into the estimated synchronous reference frame of the drive’s Field Oriented Control (FOC) scheme. The conventional FOC control scheme, low switching frequency, dc-link inductor and the inverter output three-phase filter capacitor of the medium-voltage high-power current-source drive present some challenges in the generation and design of the HF injection signal. To overcome the challenges, the FOC scheme is modified by introducing a modulation index control with a suitable dc-link current compensation to enhance the dynamic response of the injected signal and prevent any clamp in the injected signal. In addition, a Multisampling Space Vector Modulation (MS-SVM) method is proposed to prevent the distortion in the HF signal due to a low switching frequency to injected signal ratio. It is found that by using the proposed FOC scheme and multisampling modulation scheme, and proper design of the HF signal, an accurate rotor flux angle can be estimated for sensorless zero/low speed operation. Moreover, a novel input power factor compensation method is proposed for a high-power pulse-width-modulated Current-Source-Converter (CSC)-fed Permanent Magnet Synchronous Motor (PMSM) drive system. The proposed method is based on controlling the d-axis stator current component in the field-oriented control scheme of the drive system. The main feature of the proposed scheme is to compensate for the line-side power factor without the need for modulation index control in either the rectifier or the inverter. Simulation and experimental verification for various objectives are provided throughout the thesis. The results validate the proposed solutions for the main challenges of zero/low speed operation of sensorless Current-Source-Converter (CSC)-fed Permanent Magnet Synchronous Motor (PMSM) drive system.

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