Ali Ahmed Adam

Torque Ripple and EMI Noise Minimization in PMSM Using Active Filter Topology and Field-Oriented Control

This paper proposes an active filter (AF) topology to reduce the torque ripple and harmonic noises in a permanent-magnet synchronous motor. The topology consists of an insulated-gate bipolar transistor AF and two resistance-inductance-capacitance high-pass electromagnetic interference (EMI) noise filters, i.e., one in the primary and the other in the secondary circuit of the coupling 1:1 transformer. The AF is characterized by detecting the harmonics in the motor phase voltages by comparing the measured phase values with the reference voltages generated as a function of the motor parameters and control setting values under field-oriented control. The AF uses the hysteresis voltage control method, while the motor main circuit uses the hysteresis current control method; thus, the two control methods independently work together to provide an almost sinusoidal voltage to the motor windings. The simulation results show total harmonic distortion drops of greater than 13% with EMI noise damping down to ~-10 dB as well as considerable reduction in torque ripple.

A Novel Direct Torque Control Algorithm for IPMSM With Minimum Harmonics and Torque Ripples

This paper describes a new direct torque control algorithm for interior permanent-magnet synchronous motor (IPMSM) to improve the performance of hysteresis direct torque control (HDTC). The algorithm uses the output of two hysteresis controllers used in the traditional HDTC to determine two adjacent active vectors. It also uses the magnitude of the torque error and stator flux linkage position to select the switching time required for the two selected vectors. The selection of the switching time utilizes the suggested table structure, which reduces the complexity of calculation. The simulation results of this proposed algorithm show adequate dynamic torque performance and considerable torque ripples reduction as well as lower harmonic current as compared to HDTC

High-Frequency Common-Mode Modeling of Permanent Magnet Synchronous Motors

In this paper, a model for permanent magnet synchronous motors to deal with high-frequency emissions from an inverter system is proposed and analyzed. The model permits study of the common-mode (CM) effects on the motor line currents. The experimental measurements show that the CM stray capacitors are not affected by rotor magnet positions. The simulated and experimental results show that the CM currents increase with decreasing sampling time.

Adaptive neural network based controller for direct torque control of PMSM with minimum torque ripples

An artificial neural network (ANN) based controller for permanent magnet synchronous motor (PMSM) under direct torque control (DTC) algorithm is proposed to minimize the torque ripples associated with hysteresis direct torque control (HDTC). In this system, the stator flux position, stator flux error and developed torque error are used to select two active vectors while at the same time, the normalized absolute value of these ones are used in artificial neural network algorithm block to adapt the switching of the inverter in order to control the applied average voltage level in such a way to minimize the torque ripples. Thus, it includes the capability of ANN to learn from processes and the fast response feature of the DTC. The simulated results show considerable torque ripple and current ripple reduction as well as electromagnetic interference (EMI) noise level reduction. The simulated results are supported with some experimental results.

Compound passive filter to minimize torque ripples and EMI noises in PMSM drives

This paper proposes a compound passive filter topology to reduce torque ripples and harmonic noises in permanent magnet synchronous motor (PMSM) derived by field oriented control. The compound filter has two tuning frequency setting points, one at inverter switching frequency and the other at some average selected frequency. The filter topology is characterized by affecting inverter switching frequency in such a way to decrease stress on switching elements. The filter topology uses series dissipative elements to reshape motor voltage waveform to provide semi-sinusoidal voltage to the motor windings. The simulation results show that the proposed topology is effectively reduces torque ripples as well as total harmonic distortion (THD) and electromagnetic interference (EMI) noise level.

Decoupled State-Feedback Based Control Scheme for the Distributed Generation System

Abstract This article presents a new development for the decoupled state-feedback control to operate the distribution generation unit (DGU) within an efficient distribution generation system (DGS). The developed decoupled state-feedback is better than the conventional voltage vector control and sliding mode control for dealing with active and reactive power. Therefore, it is embraced to form a new control scheme, which is employed to effectively decouple and precisely control the injected active and reactive power to the distribution system. A five-level diode-clamped inverter is adopted to build the DGU in order to minimize the injected harmonics, facilitate the operation of the proposed control scheme, and ease the design of its passive filter. The proposed control scheme enables the DGS to be functional in several operational modes such as grid-connected, intentional islanding, unintentional islanding, anti-islanding, and ride-through modes. The effectiveness of the proposed control scheme is proved through the simulation results for all foregoing modes. Experimental results are provided to show how the proposed concepts are practically implemented to control the voltage of the DGU so that the active power and reactive power are exchanged between the power grid and the DGS in the grid-connected mode.

Multilevel inverter operated by voltage orientation control

This paper presents an innovative control scheme for the multilevel inverter that is connected to the power grid as a Distributed Generation unit, DG. The paper demonstrates novel application for the voltage orientation control, also called voltage vector control, so as to precisely control active and reactive power injected by the distributed generation units in a normal operation of the system, (grid-connected mode), and it works as a voltage source in an islanding mode. The adopted topology for the DG is the diode clamped multilevel inverter structure in order to minimize the injected harmonics and get rid of a sophisticated passive filter. The utilization of the voltage vector control scheme is optimized so that the DG unit can precisely control the instantaneous power injected to the power grid. The presented simulation results verify the capability of the suggested control to precisely adjust the active and reactive power based on set-values.

A novel multilevel DC chopper supplying DC motor

This paper deals with controlling DC motor speed and/or torque through the multilevel Chopper circuit. The proposed switching circuit consists of four cascaded switching elements with three clamping diodes and four equal or different voltage sources connected in series. The configuration provides a constant five levels of voltage and has the ability to generate and track any reference input voltage within the source voltage range. The generated voltage has relatively very small harmonic and ripples compared to the traditional step down chopper. The profile of the generated voltage positively affects the performance of the motor armature current, the generated dynamic torque and the rotor. The simulation results show adequate voltage reference tracking, smooth speed response and reduced current and torque ripples, which normally reflect in smaller mechanical vibration and acoustic noise.

Torque Control of PMSM and Associated Harmonic Ripples

Vector control techniques have made possible the application of PMSM motors for high performance applications where traditionally only dc drives were applied. The vector control scheme enables the control of the PMSM in the same way as a separately excited DC motor operated with a current-regulated armature supply where then the torque is proportional to the product of armature current and the excitation flux. Similarly, torque control of the PMSM is achieved by controlling the torque current component and flux current component independently. Torque Control uses PMSM model to predict the voltage required to achieve a desired output torque or speed. So by using only current and voltage measurements (and rotor position in sensor controled machine), it is possible to estimate the instantaneous rotor or stator flux and output torque demanded values within a fixed sampling time. The calculated voltage is then evaluated to produce switching set to drive the inverter supplying the motor. PMSM torque control has traditionally been achieved using Field Oriented Control (FOC). This involves the transformation of the stator currents into a synchronously rotating d-q reference frame that is typically aligned to the rotor flux. In the d-q reference frame, the torque and flux producing components of the stator current can separately be controlled. Typically a PI controller is normally used to regulate the output voltage to achieve the required torque. Direct Torque Control (DTC), which was initially proposed for induction machines in the middle of 1980’s (Depenbrock, 1984 and 1988; Takahashi, 1986), was applied to PMSM in the late 1990s (French, 1996; Zhong, 1997). In the Direct Torque Control of the PMSM, the control of torque is exercised through control of the amplitude and angular position of the stator flux vector relative to the rotor flux vector. Many methods have been proposed for direct torque control of PMSM among which Hysteresis based direct torque control (HDTC) and Space Vector Modulation direct torque control (SVMDTC). In 2009 Adam and Gulez, introduced new DTC algortim for IPMSM to improve the performance of hysteresis direct torque control. The algorithm uses the output of two hysteresis controllers used in the traditional HDTC to determine two adjacent active vectors. The algorithm also uses the magnitude of the torque error and the stator flux linkage position to select the switching time required for the two selected vectors. The selection of

A direct torque control algorithm for permanent magnet synchronous motors with minimum torque pulsation and reduced electromagnetic interference noise

In this work, a sensorless hysteresis direct torque control (HDTC) algorithm for a permanent magnet synchronous motor is described. The algorithm uses the output of two hysteresis controllers used in the traditional HDTC to determine two adjacent switching vectors per one sample time. The algorithm also uses the magnitude of the torque error, magnitude of the flux error and stator flux position to select the switching time for the selected vectors. The selection of the switching time utilises table structure which reduces the complexity of calculation. The simulation results of this proposed algorithm show adequate dynamic torque performance and considerable torque ripples reduction as well as lower current ripples and reduced electromagnetic interference noise level, as compared with HDTC.