Predictive Control for Power Converters and Drives: Concept, Applications, and Trends

Ralph M. Kennel,Jose Rodriguez,Zhenbin Zhang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Predictive Control for Electrical Drives-A Survey

Ralph Kennel,Arne Linder 전력전자학회 2001 ICPE(ISPE)논문집 Vol.2001 No.10

During the last decades several proposals have been made in literature to use predictive control for inverter control - especially in electrical drives. These algorithms are completely different to the recursive but linear predictive algorithms known from information theory, where closed mathematical equations are used (e g Kalman-filters)<br/> Only few of the presented schemes have been realized in industrial applications so far After some further progress, however, the advan­tage of predictive algorithms might lead to an increased number of industrial implementations in the future.<br/> Besides the common basic idea - to use the well-known but strongly non-linear behaviour of inverters to precalculate the best switching times - there are many differences in the details of these proposals This contribution shows similarities and differences and attempts to design a "family tree" of predictive control algorithms This might grow to a first step to a theoretical approach to deal with predictive control schemes in a more generalised way.<br/>

Interleaved or Sequential Switching - for Increasing the Switching Frequency

ANDRE CABRAL FERREIRA,RALPH M. KENNEL 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-

Using several IGBTs in parallel it is possible to operate standard IGBTs with higher switching frequencies than usual. Based on this concept the current load and thermal losses are split between the paralleled devices. The free wheeling diodes, however, cannot be controlled actively and therefore do not share in sequential switching. In 3-phase VSI applications there is the danger of overloading one of the paralleled free wheeling diodes. This paper presents a concept of magnetic freewheeling control resulting in the free wheeling current following the same sequential concept as in the IGBTs. Magnetic freewheeling control makes sequential switching applicable to 3-phase voltage source inverters (VSI).

An Efficient Method to Calculate Optimal Pulse Patterns for Multi-Level Converters

Reza Fotouhi,Alexey Sorokin,Ralph Kennel,Hendrik du Toit Mouton 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Optimal Pulse Patterns (OPPs) permit setting the switching frequency of power converters to a low value without compromising on Total Harmonic Distortion (THD). The optimization, which is performed offline, is a slow procedure. For instance a normal PC might need up to several weeks to calculate OPPs for a five-level converter. This paper presents a general algorithm for calculating OPPs for multi-level converters. Where calculation time is highly reduced via reformulation of optimization problem and choosing proper initial values. The calculation procedure is explained in detail and compared with standard optimization algorithm for a five-level inverter.

Robust Deadbeat Control for Synchronous Machines rejecting Noise and Uncertainties by Predictive Filtering

Jean-Francois Stumper,Sascha Kuehl,Ralph Kennel 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

A predictive current control scheme for permanentmagnet synchronous motors (PMSMs) with deadbeat performance is presented. Major problems of such control schemes are the delay of the discrete control system, machine parameter uncertainties and measurement noise. With conventional methods, the delay can be easily compensated, but the effects of uncertainties can only be handled when they are comparably slow. This paper presents a new filtering method that attenuates the negative effects of parameter uncertainties in fast transients. The predictive controller inputs are actual measurements averaged with previous current predictions. As a result, the stability range is extended, and the oscillations caused by parameter uncertainties are damped. Noise sensitivity is also reduced. The system response is not slowed down. The results are confirmed analytically and experimentally.

Model Predictive Control with Extrapolation Strategy for the Arm Current Commutation Control of Modular Multilevel Converter Operating in Quasi Two-Level Mode

Xiaonan Gao,Wei Tian,Zhenbin Zhang,Ralph Kennel 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Modular multilevel converters (MMCs) have become an attractive topology for medium-voltage motor drive applications due to their modular construction and voltage scalability. The main drawback of using MMC to drive motors is the large voltage variation of submodule (SM) capacitors when the motor is running at a low speed with a large load torque condition. Operating in the quasi two-level mode of MMCs is an effective solution for such a problem. The arm current commutation control is the most important part for the operation of MMCs in the quasi two-level mode. This paper proposes a new current commutation method. The general idea is to use the delay control method to realize the arm current commutation. Therefore, the key point is to decide when to delay the operation of a submodule at each step during the commutation process. In this paper, the model predictive control (MPC) method with extrapolation technique has been used to determine whether to delay the SM at the present moment. Therefore, the waveforms of the two arms in the same phase may not be completely complementary throughout the whole commutation period. Due to such non-complementary PWMs, the currents between two arms can be exchanged.

Encoderless Field-Oriented Control of a Synchronous Reluctance Machine with Position and Inductance Estimators

Dirk Paulus,Jean-Francois Stumper,Peter Landsmann,Ralph Kennel 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

A rotor position estimator for a synchronous reluctance machine (SynRM) is presented. The rotor position is directly calculated based on stator current measurements and voltage commands. For position information, two machine parameters are required, stator resistance and average inductance. The average inductance is estimated online as it is operation-point dependent. The two estimators are linearly independent and can be combined. The performance is demonstrated with experimental results.

Current Balancing Control of High Power Parallel-Connected AFE with Small Current Ripples

Xinbo Cai,Zhenbin Zhang,Liang Cai,Ralph Kennel 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Parallel connected Active Front End (AFE) voltage converters are widely employed in high-power grid interfaces for renewable energy applications. With parallel connected two level power converters, the power rating of the system can be easily increased with higher stability and less control efforts than multilevel power converter based solutions. However, due to unmatched modules, unbalanced currents inevitably happen to different modules of the same phase, which seriously impacts the efficiency and performances of the converter. This paper presents an improved current balancing control methods for a high power (600 kVA) parallel connected AFE for wind energy applications. The proposed current balancing method is integrated within a well-known Voltage Oriented Control Scheme with few implementation efforts. The simulation results show that with the proposed strategy the current ripples of each parallelconnected converter leg decrease evidently and the THDs are therefore decreased. Moreover, the effectiveness of the proposed method is also confirmed by experimental results with a grid-code compatible testing set-up.

Decoupling of the Secondary Saliencies in Sensorless PMSM Drives using Repetitive Control in the Angle Domain

Wu, Chun,Chen, Zhe,Qi, Rong,Kennel, Ralph The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4

To decouple the secondary saliencies in sensorless permanent magnet synchronous machine (PMSM) drives, a repetitive control (RC) in the angle domain is proposed. In this paper, the inductance model of a concentrated windings surface-mounted PMSM (cwSPMSM) with strong secondary saliencies is developed. Due to the secondary saliencies, the estimated position contains harmonic disturbances that are periodic relative to the angular position. Through a transformation from the time domain to the angle domain, these varying frequency disturbances can be treated as constant periodic disturbances. The proposed angle-domain RC is plugged into an existing phase-locked loop (PLL) and utilizes the error of the PLL to generate signals to suppress these periodic disturbances. A stability analysis and parameter design guidelines of the RC are addressed in detail. Finally, the proposed method is carried out on a cwSPMSM drive test-bench. The effectiveness and accuracy are verified by experimental results.

Decoupling of the Secondary Saliencies in Sensorless PMSM Drives using Repetitive Control in the Angle Domain

Chun Wu,Zhe Chen,Rong Qi,Ralph Kennel 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.4

To decouple the secondary saliencies in sensorless permanent magnet synchronous machine (PMSM) drives, a repetitive control (RC) in the angle domain is proposed. In this paper, the inductance model of a concentrated windings surface-mounted PMSM (cwSPMSM) with strong secondary saliencies is developed. Due to the secondary saliencies, the estimated position contains harmonic disturbances that are periodic relative to the angular position. Through a transformation from the time domain to the angle domain, these varying frequency disturbances can be treated as constant periodic disturbances. The proposed angle-domain RC is plugged into an existing phase-locked loop (PLL) and utilizes the error of the PLL to generate signals to suppress these periodic disturbances. A stability analysis and parameter design guidelines of the RC are addressed in detail. Finally, the proposed method is carried out on a cwSPMSM drive test-bench. The effectiveness and accuracy are verified by experimental results.