Andre Oliveira

A High Performance Permanent Magnet Synchronous Motor Drive by using a Robust Adaptive Control Strategy

This paper presents a robust adaptive control strategy for permanent-magnet synchronous motor (PMSM) drive systems. This control scheme is based on a adaptive pole placement control strategy integrated to a sliding mode control scheme. This control strategy is applied to the machine current control loop. With this non-standard control strategy, the PMSM drive systems achieve a fast transient response and robustness to parametric uncertainties and disturbances occurred on the machine parameters owing to saturation, temperature changes and loading conditions. Simulation and experimental results are presented for showing the effectiveness of this proposed closed-loop current control strategy.

Three-phase series active power filter without DC voltage source

This paper, a three-phase series active filter without dc voltage source for voltage harmonic compensation and voltage regulation is proposed. The model of the system is derived to analyze it for general grid voltages and load conditions. Such analysis shows that it is possible to operate with a load voltage amplitude regulated at the rated reference value for some grid voltages and load conditions. Based on the system analysis, a control strategy is proposed to adequately control the system. Experimental results are presented.

Three-Phase Series Active Power Filter Without Isolation Transformer and Active DC Source

In this paper we propose two three-phase series active power filters (SAPF) for voltage harmonic compensation and voltage regulation. The power filters are conceived to operate without isolation transformer and auxiliary active dc source. The topologies are adequate for applications in which the load or grid terminals are accessible. The model of the systems are derived to analyze their behavior for general grid voltages and load conditions. Such analysis shows that it is possible to operate with a load active voltage amplitude regulated at the rated reference value for some grid voltages and load conditions. Based on the system analysis, a control strategy is proposed to adequately control the system. Experimental results for the system operating with very distorted input grid voltages are presented.

An instantaneous phase angle estimation algorithm for power converters under distorted utility conditions

This paper describes an algorithm for phase angle estimation based on symmetrical sequence components. The algorithm uses the recursive weighted least-squares method to estimate the fundamental component of the positive and negative sequences. The phase angle is estimated at each iteration from the fundamental component of positive sequence. The proposed method eliminates low order harmonics and dc offset in the sampled variable. The operation of the algorithm under this distorted utility condition is presented. Simulation and experimental results validate the theoretical approach.

Hybrid pulse width modulation for Z-source inverters

This paper presents a hybrid pulse width modulation for Z-source converter. The technique combines the theory of space-vector PWM with the ease of implementation of a triangular-comparison PWM. Such strategy reduces the effort of algorithm calculation. The introduction of the distribution ratio in this technique, allows the development of a systematic approach for implementation of either conventional or any modified vector strategies, even including the shoot-through zero vectors inherent of Z-source inverter. Also, the paper proposes a simple software algorithm to generate the hybrid modulation of Z-source inverter with the introduction of the “virtual” dc-link zero point. Simulated and experimental results demonstrate the validity of the proposed method.

Single-phase to three-phase universal active power filter

In this paper, an universal active power filter is conceived for harmonic and reactive power compensation in the single-phase to three-phase systems. A simple way to obtain the transfer functions of filter variables has been obtained, allowing new transfer functions to be easily obtained in case of structure changes. The steady state analysis allows to know the behavior of the fundamental component of currents and voltages, as well as the grid power factor. A suitable control strategy is presented to regulate the load voltage and to minimize the voltage harmonics simultaneously. Simulated and experimental results are presented.

Single-Phase Universal Active Filter Without Transformer

This paper presents an universal active filter for harmonic and reactive power compensation in single-phase system. It is a combined system of a series active filter and a shunt active filter without use of transformer. The proposed system is suitable for applications where the size is a critical factor. The model of the system is derived and it is shown that the circulating current is an important objective in the converter design. A suitable control strategy, including the PWM technique, is developed. Simulated and experimental results are presented.

A robust adaptive strategy for improving harmonic compensation in shunt active power filters

This paper investigates the use of a robust adaptive control strategy for improving the harmonic compensation in shunt active power filters (SAPF). This control scheme is applied on the filter current control loop and is based on an adaptive pole placement control strategy integrated to a variable structure control scheme (VS - APPC). This control strategy forces the supply currents to be sinusoidal with low harmonics contents. The advantage of proposed VS - APPC over conventional proportional-integral (PI) control is more flexibility, adaptive and robustness to the system parametric uncertainties or unmodeled disturbances introduced by non linear random loads. Moreover, the proposed control strategy can self-tune the controller gains which assures the system stability. Furthermore, the use of this proposed control scheme enhance performance of SAPF with fast transient response. The feasibility of the proposed control system is validated by simulation and experimental results.

Permanent-magnet synchronous machine and induction machine independently controlled by standard three-leg inverter

The objective of this paper is to propose three parallel connected motor drive systems, employing a three-phase permanent-magnet machine and a single-phase induction machine. The configurations have been designed for applications where it is necessary to control two motors independently, by using a standard three-leg inverter. All proposed solutions employ standard three-leg converters, which represents the most common commercial converter manufactured. Such topologies can be applied, for instance, with motors for traction and compression in automotive applications. The paper presents: i) relevant characteristics of the converter, such as voltage capability, shared-leg and capacitor currents; ii) pulse-width modulation techniques based on scalar approaches; iii) control strategies for providing current control; and iv) simulated and experimental results.