Eisenhawer de M. Fernandes

The Transformerless Single-Phase Universal Active Power Filter for Harmonic and Reactive Power Compensation

This paper presents a universal active filter for harmonic and reactive power compensation for single-phase systems applications. The proposed system is a combination of parallel and series active filters without transformer. It is suitable for applications where size and weight are critical factors. The model of the system is derived and it is shown that the circulating current observed in the proposed active filter is an important quantity that must be controlled. A complete control system, including pulse-width modulation (PWM) techniques, is developed. Comparisons between the structures are made from weighted total harmonic distortion (WTHD). The steady-state analysis is also presented in order to demonstrate the possibility to obtain an optimum voltage angle reducing the current amplitude of both series and parallel converters and, consequently, the total losses of the system. Simulated and experimental results validate the theoretical considerations.

Sensorless Control of a PMSM Synchronous Motor at Low Speed

This paper presents a self-sensing technique for a surface-mounted permanent-magnet synchronous machine (SM-PMSM) based on high frequency voltage injection. The reactances of the high frequency model vary as a function of rotor position and a simple method based on measured currents and voltages can be used to identify those reactances. Using the motor reactances, the rotor position and velocity are determined. The proposed technique is relatively independent of the machine parameters and it can be applied to any type of synchronous machine. The proposed technique has been tested experimentally for a commercial SM-PMSM machine. The experimental results have demonstrated the feasibility of the proposed technique

Transformerless Single-Phase Universal Active Filter With UPS Features and Reduced Number of Electronic Power Switches

This paper presents an universal active power filter for harmonic and reactive power compensation with uninterrupted power supplies (UPS) features. The configurations does not use transformer in the series part. Transformerless modern UPS systems have been rapidly replacing the old technology due to their performance and size attributes. Reducing the numbers of passive elements and/or switches in active power filters and UPS topologies not only reduces the cost of the whole system but also provides some advantages, such as great compactness, smaller weight, and higher reliability. However, the cost reduction requires the use of more complex control strategies. The model of the proposed system is derived and it is observed that the system can be reconfigurable to operate with four or three leg depending on the issue. A complete control system, including the pulsewidth modulation techniques, is developed and a comparison between the proposed filter and the standard one is done, as well. Simulated and experimental results validate the theoretical considerations.

Parameter and Speed Estimation for Implementing Low Speed Sensorless PMSM Drive System Based on an Algebraic Method

This paper presents a sensorless control scheme for a surface-mounted permanent-magnet synchronous machine (SM-PMSM) using the high frequency voltage signal injection method. The reactances of the high frequency model vary as a function of rotor position and a simple method based on measured high frequency currents and voltages is used to identify these reactances. Using such motor reactances, rotor position and velocity can be estimated. The proposed method is algebraic and does not require accurate knowledge of the initial value of the rotor position. The strategy was verified experimentally using a commercial SM-PMSM machine.

Comparison of HF signal injection methods for sensorless control of PM synchronous motors

This paper presents a comparative study of high-frequency (HF) voltage signal injections used for rotor position estimation in sensorless control of AC motors. This work reviews these methods and evaluates the performance under sensorless speed control applied to a surface permanent-magnet synchronous motor (PMSM). Theoretical analysis is verified by simulations and confirms the effectiveness of these methods. The experimental results of speed control using an industrial PMSM drive system are presented for each of the injection methods.

A metric for evaluation of the performance of saliency-tracking self-sensing control of PM motor

This paper presents a study on the performance of saliency-tracking self-sensing method for a permanent-magnet synchronous motor. It is shown that the high speed limit is a function of modulation harmonics and the extraction of the rotor information contained in the HF currents envelope as rotor speed increases. These effects degrade the rotor position signals and consequently the estimated rotor speed and the reference current. A method based on the maximum harmonic content in the reference current is detailed. The method determines the selection of observer bandwidth and the dynamic stiffness of the drive system. A complete set of simulation results is presented and validate the analysis proposed.

Self-sensing control of PMSM motor for wide-speed range operation

This work presents a self-sensing control for permanent-magnet synchronous motor (PMSM) for wide-speed range based on the integration of signal-injection and back-emf tracking methods. It is addressed an evaluation method of the transition region between these approaches based on the harmonic content of the q-axis reference current during self-sensing operation. Based on the procedure, it is established the bandwidth of the rotor position observers in function of the operation speed. It is also addressed the discussion of the attributes of implementation required for integration between the self-sensing techniques. Simulation results are presented showing the performance of the proposed self-sensing wide-speed range system.

A comparative evaluation of signal injection methods for PMSM self-sensing control

This paper presents a comparative evaluation of signal injection methods for self-sensing control of PMSM motor. Persistent voltage excitation can be performed in stationary or estimated reference-frame, this work reviews these methods and evaluates the performance under self-sensing speed control, robustness to dead-time effect, generated pulsating torque and dynamic stiffness. A complete set of simulation results are presented.

Speed sensorless control of PMSM motors implemented in real-time simulator

The paper presents a method for determining the transition region between rotor position estimators applied to permanent-magnet synchronous motors. A speed sensorless control scheme is implemented by combining the voltage injection method in low speed region, and back-emf estimation in the high speed region. The transition region is evaluated from the rms AC content level of the command current. Besides, based on this criteria, is established the bandwidths of the observers in function of the speed. Simulation are shown to verify the proposed technique. Results of the control system implemented in a real-time simulator are presented.