Odd Harmonic Repetitive Controller Research Articles

Fractional Order Feedforward Odd-Harmonic Repetitive Controller for Grid-Tied Inverters in Microgrids

Fractional Order Feedforward Odd-Harmonic Repetitive Controller for Grid-Tied Inverters in Microgrids

Control Scheme Based on Improved Odd-Harmonic Repetitive Control for Third-Harmonic Injection Two-Stage Matrix Converter

The third-harmonic injection two-stage matrix converter (3TSMC) not only inherits the advantages of the conventional two-stage matrix converter (TSMC), but also has simple modulation strategy and low switching losses. The injection current control is the key to achieving sinusoidal input currents of 3TSMC. The injection current reference consists of the third harmonic and its odd harmonics, making it difficult to obtain high control accuracy with a proportional integral (PI) controller. In this paper, a control scheme is proposed for the injection current of 3TSMC, which consists of an improved odd-harmonic repetitive controller (IORC), a PI controller and a feedforward controller. Compared with the conventional repetitive controller (CRC) and existing odd-harmonic repetitive controllers (ORC), the IORC has the highest gains and bandwidths at odd-harmonic frequencies, offering the proposed control scheme high control accuracy and fast transient response. The stability conditions of the system with the proposed control scheme are analyzed, and the design guidelines for the control parameters are provided on this basis. The experimental results demonstrate the effectiveness of the proposed control scheme.

Improved Odd-Harmonic Repetitive Control Scheme for Cuk-derived Inverter

This paper proposes an improved odd-harmonic repetitive control (IORC) scheme for a uk-derived inverter. The IORC is composed of a modified odd-harmonic repetitive controller (RC) combined with a proportional-integral (PI) controller plus a feedforward controller to achieve a zero steady-state error in the uk-derived inverter. The IORC features larger gains at odd-harmonic frequencies by modification of the conventional odd-harmonic RC. And, it also adopts a linear phase-lead compensator to compensate for the phase lag of the uk-derived inverter. Hence, the IORC can effectively eliminate the odd-harmonic components in the output current of the grid-connected uk-derived inverter. In addition, it requires less memory space and provides faster transient response compared to conventional RC schemes. However, the distinctive structure of the IORC makes it difficult to guarantee the stability of the overall control system. Thus, in this paper, a new stability analysis method for the IORC system are given, and then a practical design guideline is also provided to obtain the optimal control parameters. Experimental results are presented to validate the proposed controller in the 300-W uk-derived inverter prototype.

A novel harmonic impedance compensator based on POHMR-type RC under gird voltage distortion

The LCL-type grid-connected inverter can suppress high-frequency current harmonics but the inject grid current of the inverter will be worse under grid voltage distortion, therefore harmonic impedance compensation technology is required for this condition. The proportional Multi Resonant (PMR) controller is a feasible method for this purpose, but this scheme needs a large calculation burden and complex design. To overcome these drawbacks, a novel Proportional Odd harmonic Multi Resonant-type Repetitive Controller (POHMR-type RC) is proposed to compensate for the harmonic impedance, which means the grid voltage distortion hardly influence injected grid current. Compared to the PMR controller, the proposed scheme omits the even harmonic resonant controllers and has much more odd harmonic resonant controllers, which also reduces the memory space consumption, calculation burden and controller complexity. The proposed scheme also has better dynamic performance than conventional RC. When the proposed scheme is proposed, the inject grid current is still sinusoidal under strong grid voltage distortion and the transient response is desired. Experimental results verify the feasibility of the POHMR-type RC.

A Bouc–Wen Model-Based Compensation of the Frequency-Dependent Hysteresis of a Piezoelectric Actuator Exhibiting Odd Harmonic Oscillation

This paper proposes an enhancement of the Bouc–Wen hysteresis model to capture the frequency-dependent hysteretic behavior of a thin bimorph-type piezoelectric actuator which also exhibits odd harmonic oscillation (OHO) at specific input frequencies. The odd harmonic repetitive controller has recently been proposed to compensate for the hysteresis, and attenuates the OHO of the piezoelectric actuator for which the hysteresis nonlinearity is regarded as a disturbance. This paper proposes an alternate treatment of the hysteresis compensation with the attenuation of the OHO observed at some input frequencies. It will be shown that the proposed compensator fully utilizes the mathematical structure of the enhanced Bouc–Wen model proposed in this paper to compensate the hysteresis and to attenuate the OHO. The results of the hysteresis compensation experiment illustrate the excellent performance of the proposed control system, especially at the frequencies where OHO is conspicuous.

Multi-loop control of UPS inverter with a plug-in odd-harmonic repetitive controller

This paper proposes an improved multi-loop control scheme for the single-phase uninterruptible power supply (UPS) inverter by using a plug-in odd-harmonic repetitive controller to regulate the output voltage. In the suggested control method, the output voltage and the filter capacitor current are used as the outer and inner loop feedback signals, respectively and the instantaneous value of the reference voltage feedforwarded to the output of the controller. Instead of conventional linear (proportional-integral/-resonant) and conventional repetitive controllers, a plug-in odd-harmonic repetitive controller is employed in the outer loop to regulate the output voltage, which occupies less memory space and offers faster tracking performance compared to the conventional one. Also, a simple proportional controller is used in the inner loop for active damping of possible resonances and improving the transient performance. The feedforward of the converter reference voltage enhances the robust performance of the system and simplifies the system modelling and the controller design. A step-by-step design procedure is presented for the proposed controller, which guarantees stability of the system under worst-case scenarios. Simulation and experimental results validate the excellent steady-state and transient performance of the proposed control scheme and provide the exact comparison of the proposed method with the conventional multi-loop control method.

High performance control of a three-phase PWM rectifier using odd harmonic high order repetitive control

El objetivo de control en rectificadores de potencia trifásicos se basa en generar corrientes de entrada sinusoidales y regular el voltaje de salida DC. Aunque el Control Repetitivo y Resonante son enfoques de control que han presentado excelentes resultados, su principal desventaja se basa en la pérdida considerable de desempeño cuando la frecuencia de la red se desvía de su valor nominal. En este artículo, se presenta el uso de un Controlador Repetitivo Impar de Alto Orden para controlar los lazos de corrientes de un rectificador trifásico con un desempeño considerablemente superior a otras alternativas tradicionalmente implementadas en este campo. Este controlador permite el rechazo de los armónicos impares introducidos en el sistema, lo que mantiene una complejidad computacional similar a la obtenida con los controladores repetitivos convencionales con la ventaja de incrementar la robustez cuando la frecuencia de la señal varíe. Las simulaciones y los resultados experimentales muestran un alto desempeño aún cuando se presenten desviaciones de la frecuencia de la red respecto a su valor nominal.

High performance control of a three-phase PWM rectifier using odd harmonic high order repetitive control

El objetivo de control en rectificadores de potencia trifásicos se basa en generar corrientes de entrada sinusoidales y regular el voltaje de salida DC. Aunque el Control Repetitivo y Resonante son enfoques de control que han presentado excelentes resultados, su principal desventaja se basa en la pérdida considerable de desempeño cuando la frecuencia de la red se desvía de su valor nominal. En este artículo, se presenta el uso de un Controlador Repetitivo Impar de Alto Orden para controlar los lazos de corrientes de un rectificador trifásico con un desempeño considerablemente superior a otras alternativas tradicionalmente implementadas en este campo. Este controlador permite el rechazo de los armónicos impares introducidos en el sistema, lo que mantiene una complejidad computacional similar a la obtenida con los controladores repetitivos convencionales con la ventaja de incrementar la robustez cuando la frecuencia de la señal varíe. Las simulaciones y los resultados experimentales muestran un alto desempeño aún cuando se presenten desviaciones de la frecuencia de la red respecto a su valor nominal.

Robust Repetitive Current Control of Two-Level Utility-Connected Converter using LCL Filter

This paper investigates the implementation and performance limits of conventional and odd-harmonic repetitive controllers used for current control of two-level grid-connected inverter. This research is motivated by the relatively poor performance of classical (PI) controller when utility voltage has high harmonic distortion. Repetitive controllers (RCs) have the ability to track or reject periodic signals. However, their effectiveness is limited severely by the scarce bandwidth of the plant. To address this issue, the relationship between plant bandwidth and the converter’s LCL filter is also investigated. In addition, the effects of variation in parameters of low-pass filter used in RC loop on the performance of the system are studied. Odd-harmonic repetitive controller (ORC) is used to overcome the excessive memory requirement in RC implementation. The performance of RC and ORC is tested for different total harmonic distortion (THD) values of utility voltage. The results show that RC improves steady state error and THD of the output current. Also, RC is found to be robust under variations in output-side inductance.

Analysis and design of a robust odd-harmonic repetitive controller for an active filter under variable network frequency

Frequency variations in the electrical network may cause a dramatic performance decay in repetitive controlled active filters intended to remove odd-harmonic distortion in single-phase AC loads. This work presents an odd-harmonic repetitive controller for a shunt active power filter that addresses such a performance problem. This is achieved by means of an adaptive change of the sampling period of the digital controller. However, this action implies structural changes that may result in an overall destabilization of the closed-loop system. Hence, a small-gain theorem-based robust control design technique allows to obtain a controller which assures BIBO stability in the required sampling period interval. Experimental results validate the proposal.

Zero-phase odd-harmonic repetitive controller for a single-phase PWM inverter

In this paper, a zero-phase odd-harmonic repetitive control scheme is proposed for pulse-width modulation inverters. The proposed repetitive controller combines an odd-harmonic periodic generator with a noncasual zero-phase compensation filter. It occupies less data memory than a conventional repetitive controller does. Moreover, it offers faster convergence of the tracking error, and yields very low total harmonics distortion (THD) and low tracking error. Analysis and design of the proposed system are presented. Experimental results with the proposed repetitive controller are presented to validate the approach. The phenomena of even-harmonic residues in the proposed control system is discussed and experimentally demonstrated.