Control of Boost Converter Module for Open-End Winding Permanent Magnet Motor Based, Dual Inverter Drive

This work explains how to control a boost converter module to vary the DC link voltage of a dual inverter motor drive. Doing so is shown to extend the speed range of open-end winding permanent magnet synchronous motors (OWPMSM) compared to using flux weakening control, enabling the use of more efficient and power dense high-speed motors. Such a speed range can be obtained by simply increasing the battery voltage, thus increasing the DC link voltage, and using flux weakening control. However, depending on the rebalancing technique used, cell imbalances in high-voltage batteries can decrease the efficiency and/or the battery lifetime, both of which are sensitive metrics in electric vehicles (EVs). Splitting the required battery voltage between two independent sources to drive the OWPMSM and using the boost converter modules to further increase the DC link voltage as needed extends the speed range while keeping the individual battery voltages low enough to prevent exacerbating cell-balancing issues. Furthermore, by adding the boost converter modules, the motor drive can satisfy the maximum torque per ampere (MTPA) condition at all speeds. Doing so decreases the maximum stator current above base speed compared to flux weakening control while maintaining the same torque-speed curve, thus lowering conduction losses. Simulation results from PLECS confirm the extended speed range and lower conduction losses of the topology compared to a conventional permanent magnet synchronous motor (PMSM) drive and a dual inverter drive without the boost converter modules

Control Strategies for Open-End Winding Drives Operating in the Flux-Weakening Region

This paper presents and compares control strategies for three-phase open-end winding drives operating in the flux-weakening region. A six-leg inverter with a single dc-link is associated with the machine in order to use a single energy source. With this topology, the zero-sequence circuit has to be considered since the zero-sequence current can circulate in the windings. Therefore, conventional over-modulation strategies are not appropriate when the machine enters in the flux-weakening region. A few solutions dealing with the zero-sequence circuit have been proposed in literature. They use a modified space vector modulation or a conventional modulation with additional voltage limitations. The paper describes the aforementioned strategies and then a new strategy is proposed. This new strategy takes into account the magnitudes and phase angles of the voltage harmonic components. This yields better voltage utilization in the dq frame. Furthermore, inverter saturation is avoided in the zero-sequence frame and therefore zero-sequence current control is maintained. Three methods are implemented on a test bed composed of a three-phase permanent-magnet synchronous machine, a six-leg inverter and a hybrid DSP/FPGA controller. Experimental results are presented and compared for all strategies. A performance analysis is conducted as regards the region of operation and the machine parameters.Projet SOFRACI/FU

Field oriented control of permanent magnet synchronous motor with third-harmonic injection pulse width modulation to reduce quadrotors’ speed ripples

The world’s commercial unmanned aerial vehicle (UAV) industry has witnessed unprecedented boom in recent years. Delighted with an ample supply of this excellent high-tech product, global consumers are paying more attention on UAVs. Civilian UAVs now vastly outnumber military ones, with the estimate of over a million sold by 2016. An UAV has various degrees of autonomy as enabled by the use and precise control of motors. Traditional Direct Current (DC) motors are replaced by permanent magnet synchronous motors (PMSM) associated with the new power electronic inverters. Because of a PMSM’s higher power density than a DC motor, it reduces the rotor losses, thus improving its efficiency. The other improvement comes from the advanced control methods. The simple drive system based on a DC motor with open-loop control is outdated. High frequency switches in power electronic inverters offer an opportunity to change motor input voltage values and frequencies faster than ever before. Vector control approaches are employed with closed-loop feedback control, which brings high precision and good dynamics. Integrated inverter-motor drive systems are in progress. This thesis focuses on how to control PMSM installed in the UVAs with a high performance of dynamic response and fewer speed ripples. Field Oriented Control (FOC) is one type of vector controls to control a PMSM in a quadrotor. FOC of PMSM and Pulse Width Modulation (PWM) are introduced. The simulation results of FOC of PMSM with third-harmonic injection PWM and traditional FOC are compared. This comparison proves that FOC of PMSM with third-harmonic injection provides a better dynamic response for a quadrotor’s movement in vertical direction. In addition, since PWM is helpful to reduce the speed ripples, PMSM has a better steady-state response during operations

Torque Control

This book is the result of inspirations and contributions from many researchers, a collection of 9 works, which are, in majority, focalised around the Direct Torque Control and may be comprised of three sections: different techniques for the control of asynchronous motors and double feed or double star induction machines, oriented approach of recent developments relating to the control of the Permanent Magnet Synchronous Motors, and special controller design and torque control of switched reluctance machine

Methods of resistance estimation in permanent magnet synchronous motors for real-time thermal management

Real-time thermal management of electrical ma- chines relies on sufficiently accurate indicators of internal tem- perature. One indicator of temperature in a permanent-magnet synchronous motor (PMSM) is the stator winding resistance. Detection of PMSM winding resistance in the literature has been made on machines with relatively high resistances, where the resistive voltage vector is significant under load. This paper describes two techniques which can be applied to detect the winding resistance, through ‘Fixed Angle’ and ‘Fixed Mag- nitude’ current injection. Two further methods are described which discriminate injected current and voltages from motoring currents and voltages: ‘Unipolar’ and ‘Bipolar’ separation. These enable the resistance to be determined, and hence the winding temperature in permanent-magnet machines. These methods can be applied under load, and in a manner that does not disturb motor torque or speed. The method distinguishes between changes in the electro-motive force (EMF) constant and the resistive voltage. This paper introduces the techniques, whilst a companion paper covers the application of one of the methods to a PMSM drive system

Vector Control and Experimental Evaluation of Permanent Magnet Synchronous Motors for HEVs

The 2004 Toyota Prius exceeded sales expectations and led the automotive industry to realize that there is a healthy market for hybrid electric vehicles (HEVs). The Prius uses two interior permanent magnet motors to manipulate power flow throughout the drive system. Permanent magnet synchronous motors (PMSMs) are most suitable for HEVs and full electric vehicles due to their high efficiency, high power density, and fast dynamic response. This thesis will present vector control theory for PMSMs, with focus on interior permanent magnet motors. The primary 50kW drive motor and inverter of the 2004 Toyota Prius Synergy drive system was removed for an intensive thermal, electrical, and mechanical evaluation in a dynamometer test cell at Oak Ridge National Laboratory. These evaluations include locked rotor, back-EMF, and motoring operation region tests. The resulting data is presented to reveal characteristics such as torque capabilities, thermal limitations, and motor efficiencies for all toque-speed operation points. One of the most challenging tasks of the evaluation was to solve problems related to electromagnetic interference (EMI). The pulse width modulation (PWM) driven high voltage converter/inverter is a large source of electromagnetic field radiation and nearby low level signals, including control circuitry for the hybrid system, will experience EMI if proper countermeasures are not taken. Methods to reduce electromagnetic field radiation and practices to prevent EMI are discussed

Applications of Switch-Mode Rectifiers on Micro-grid Incorporating with EV and BESS

A switch-mode rectifier (SMR) can provide adjustable and well-regulated DC output voltage from the available AC source with good line drawn power quality. Depending on the input/output voltage transfer characteristics, the schematics, the operation quadrant, and control, SMRs possess many classifications and application. Typical potential application examples include grid powered motor drives, battery chargers, various power electronic facilities, micro-grids, and grid-connected battery energy storage system (BESS), etc. In micro-grids, the SMR can be employed as the AC generator-followed converter to yield better generating efficiency. The SMR operation of its grid-connected inverter let the grid-to-microgrid (G2M) operation be conductable in addition to the microgrid-to-grid (M2G) operation. As for the electric vehicle (EV), the bidirectional inverter can be arranged to perform G2V/V2G operations in idle case, wherein the SMR operation is made in G2V battery charging

Direct Power Control Algorithm for Electric Traction Systems

In this paper presents a direct power control-based algorithm is used for general filtering and unbalance compensation scheme for electric traction systems. This method can improve the power flow exchange between the grid and the load . As a result unbalanced load is seen as a balanced linear load. The proposed filter is evaluated on power substations for two-level and dual-converter in the power stage. This method is experimented simulated and shown a better oerformance