Current-mode control for sensorless BDCM drive with intelligent commutation tuning

The winding current response speed and the adequate commutation significantly affect the control performance of a sensorless brushless dc motor (BDCM) drive. In this paper, the studies about these two issues to enhance the performance of BDCM drive are made. First, the sensorless inverter-fed BDCM drive with a proposed current command generation scheme is established. An intelligent commutation instant tuning technique is developed to pursue better motor torque generating characteristics. For achieving this goal, the motor drawn line current minimization is employed as the performance index in making the commutation tuning. After generating the current command with adequate commutation, a robust current-mode controller is further developed and applied to greatly speed up the square wave current tracking response and the response is rather insensitive to the machine parameter and back electromotive force (back-EMF) changes. In Addition, a simple starting method and a speed estimation approach are also proposed. Some experimental results are provided to demonstrate the validity of the proposed control method.     

一种新的BLDCM无传感器梯形控制方法

无传感器无刷直流电机主要采用反电动势法进行控制,但该控制方法中的各种干扰会引起无传感器BLDCM的反电动势波形产生毛刺和纹波,这将导致对反电动势过零点的错误判断。文中提出了一种无传感器BLDCM的控制方法,使用提出的优选函数对反电动势过零检测结果进行滤波。通过分析反电动势波形并使用优选函数对反电动势过零点附近的毛刺脉冲和纹波进行数字滤波,避免了对反电动势过零点产生误判,得到了电机驱动电压的换相时刻,提高了对电机的精确控制。实验结果证明了新BLDCM无传感器梯形控制方法的正确性和可行性。     

四旋翼飞行器无刷直流电机调速系统的设计

提出了一种适用于飞行器上的无传感器型无刷直流电机的控制方案。采用ATmega8作为系统控制器,利用片内模拟比较器,通过比较电机非导通绕组的反电动势与虚拟中点电压得到过零点时刻,并延迟30°电角度作为电机换相时刻。利用MOS管设计了三相桥式驱动电路,采用单边PWM控制方式实现电机调速,采用三段式启动方法实现了电机的软启动。软硬件结合实现了MOS管自检、过流保护、欠压保护的功能,提高了系统的安全性。实验表明,调速系统性能良好,能正常驱动新西达2217外转子式无刷直流电机。     

基于反电势线性拟合的无霍尔BLDC驱动方法

对于以反电势过零点判断来控制无感直流无刷电机的方案,在驱动的低速阶段,由于反电动势值过小,难以准确地检测过零点,针对该问题,提出一种新的低速反电势过零检测方法。该方法在低速采用线性拟合代替硬件判断反电势过零点,并在PWM_OFF时刻进行反电势采样,提高了低速阶段的控制性能,通过Matlab的Simulink仿真证明该方案切实可行。     

Load-Commutated SCR Current-Source-Inverter-Fed Induction Motor Drive With Sinusoidal Motor Voltage and Current

Current source inverter (CSI) is an attractive solution in high-power drives. The conventional gate turn-off thyristor (GTO) based CSI-fed induction motor drives suffer from drawbacks such as low-frequency torque pulsation, harmonic heating, and unstable operation at low-speed ranges. These drawbacks can be overcome by connecting a current-controlled voltage source inverter (VSI) across the motor terminal replacing the bulky ac capacitors. The VSI provides the harmonic currents, which results in sinusoidal motor voltage and current even with the CSI switching at fundamental frequency. This paper proposes a CSI-fed induction motor drive scheme where GTOs are replaced by thyristors in the CSI without any external circuit to assist the turning off of the thyristors. Here, the current-controlled VSI, connected in shunt, is designed to supply the volt ampere reactive requirement of the induction motor, and the CSI is made to operate in leading power factor mode such that the thyristors in the CSI are autosequentially turned off. The resulting drive will be able to feed medium-voltage, high-power induction motors directly. A sensorless vector-controlled CSI drive based on the proposed configuration is developed. The experimental results from a 5 hp prototype are presented. Experimental results show that the proposed drive has stable operation throughout the operating range of speeds.     

A generalized approach to steady-state analysis of a current-sourceinverter with induction motor load including commutation overlap

A generalized state-space approach is presented for the steady-state commutation analysis of an autosequential commuted current-source inverter-fed induction motor drive covering all possible modes of operation using a digital computer. The analysis adopts the basic per-phase equivalent circuit for the induction motor model, includes the effect of DC link filter impedance and the variation of back EMF during the commutation interval, and extends the inverter model to cover the complex commutation overlap mode occurring during high frequency operation. A digital computer program is evolved, to identify automatically the relevant sets of equations applicable to a particular mode from a generalized set of equations and to solve them     

Low-cost sensorless control of brushless DC motors with improved speed range

This paper presents a low-cost position sensorless control scheme for brushless dc motors. Rotor position information is extracted by indirectly sensing the back EMF from only one of the three motor-terminal voltages for a three-phase motor. Depending on the terminal voltage sensing locations, either a low-pass filter or a band-pass filter is used for position information retrieval. This leads to a significant reduction in the component count of the sensing circuit. The cost saving is further increased by coupling the sensing circuit with a single-chip microprocessor or digital signal processor for speed control. In addition, a look-up-table-based correction for the nonideal phase delay introduced by the filter is suggested to ensure accurate position detection even at low speed. This extends the operating speed range and improves motor efficiency. Experimental results are included to verify the proposed scheme.     

用dsPIC30F3010实现无刷直流电机的无传感器控制

基于无刷直流电机的反电动势过零点检测法,用dsPIC30F3010对电机端电压进行检测得到电机的反电动势过零点,进而得到转子的位置信息,以此控制电机换相,从而实现无刷直流电机的无传感器控制.     

基于单周期控制的PWM电流控制系统设计与实现

针对无刷直流电机（BLDC）驱动器的电流控制问题,在本文中提出了一种改进的基于单周控制的低成本转子位置估算方法。该估算方法以真实反电势过零点的检测为依据,这些真实反电势过零点可直接通过检测相端和直流环节中点之间的电压来提取,无需电机中性点电压。电流控制系统通过一种低成本的通用自动电压调整微控制器（Atmega8）来实现。MATLAB仿真和实验测试结果均显示相比传统的滞环控制器方法,改进后的PWM（脉冲宽度调制）无刷直流电机电流控制系统在稳态和瞬态两种情况下表现出更好的性能。     

无位置传感器无刷直流电机启动的新方法研究

针对无位置传感器无刷直流电机的启动问题,提出了对三段式闭环启动中的预定位、外加速过程的改进方法。在转子定位阶段采用基于空间电压矢量调制的短时脉冲来获得转子初始位置,精度可达15°。加速阶段采用施加空间电压矢量,通过检测母线电流变化率确定换相时刻,当速度达到额定转速的80%后,通过反电动势法进行换相。通过仿真分析可知,该方法能够有效的实现电机启动,并提高了启动的可靠性。     

Design of a sensorless commutation IC for BLDC motors

This paper presents the design and realization of a sensorless commutation integrated circuit (IC) for brushless DC motors (BLDCMs) by using mixed-mode IC design methodology. The developed IC can generate accurate commutation signals for BLDCMs by using a modified back-EMF sensing scheme instead of using Hall-effect sensors. This IC can be also easily interfaced with a microcontroller or a digital signal processor (DSP) to complete the closed-loop control of a BLDCM. The developed sensorless commutation IC consists of an analog back-EMF processing circuit and a programmable digital commutation control circuit. Since the commutation control is very critical for BLDCM control, the proposed sensorless commutation IC provides a phase compensation circuit to compensate phase error due to low-pass filtering, noise, and nonideal effects of back-EMFs. By using mixed-mode IC design methodology, this IC solution requires less analog compensation circuits compared to other commercially available motor control ICs. Therefore, high maintainability and flexibility can be both achieved. The proposed sensorless commutation IC is integrated in a standard 0.35-/spl mu/m single-poly four-metal CMOS process, and the realization technique of this mixed-mode IC has been given. The proposed control scheme and developed realization techniques provide illustrative engineering procedures for the system-on-a-chip solution for advanced digital motor control. Simulation and experimental results have been carried out in verification of the proposed control scheme.     

Mechanical sensorless speed control of permanent-magnet AC motors driving an unknown load

A new sensorless scheme for high-performance speed control of permanent-magnet ac motors (PMACMs) driving an unknown load is proposed. This scheme uses an extended nonlinear reduced-order observer to estimate the induced electromotive force (EMF) and load torque. From the estimated variables, the rotor position, the rotor speed, and the position derivative of flux are calculated and are used to close the control loop. In order to improve the drive performance, the estimated load torque is incorporated as a feedforward signal in the closed control loop. In addition, the proposed sensorless PMACM drive allows the torque-ripple and copper-loss minimization for motors with an arbitrary EMF waveform. Simulation and experimental results to validate the proposal are presented in this paper.     

A novel CSI-fed induction motor drive

Current source inverter (CSI) fed drives are employed in high power applications. The conventional CSI drives suffer from drawbacks such as harmonic resonance, unstable operation at low speed ranges, and torque pulsation. This paper presents a novel CSI drive which overcomes all these drawbacks and results in sinusoidal motor voltage and current even with CSI switching at fundamental frequency. The proposed CSI drive uses a three-level inverter as an active filter across motor terminals replacing the bulky ac capacitors used in the conventional drive. A sensorless vector controlled CSI drive based on proposed configuration is developed. The simulation and experimental results are presented. Experimental results show that the proposed drive has stable operation even at low speeds. Comparative results show that the proposed CSI drive has improved torque ripple compared to the conventional configuration.     

An improved sensorless driving method for SRM using a phase-shift circuit technique

This paper presents an improved sensorless driving method for switched reluctance motor (SRM) using a phase-shift circuit technique. The conventional method consists of impressing short voltage pulses during unenergized phases, measuring the phase current pulses, and finding the correlation between the filtered current signals and rotor position. However, the filtering process causes a signal phase delay which varies with motor speed. This delay must be compensated for in providing the sensorless signal which is proper to the rotor position. A solution for this phase delay compensation, based on a simple analog and digital circuit, is proposed in this paper.     

A harmonic elimination and suppression scheme for an open-end winding induction motor drive

In this paper, a harmonic elimination and suppression scheme for a dual-inverter-fed open-end winding induction motor drive is presented. Two isolated dc-link sources with voltage ratio of approximately 1 : 0.366 are required for the present drive. These two isolated do links feeding two inverters to drive the open-end winding induction motor eliminate the triplen harmonic currents from the motor phase. The pulsewidth-modulation scheme proposed enables the cancellation of all the 5th- and 7th-order (6n /spl plusmn/ 1, where n = 1, 3, 5, 7, etc.) harmonic voltages and suppresses the 11th- and 13th-order harmonic voltage amplitudes in the motor phase voltage, in all modulation ranges. The next higher order harmonics present in the motor phase voltages are 23rd, 25th, 35th, 37th etc. (6n /spl plusmn/ 1, n = 4, 6, etc.). By using triangular carrier wave and proper modulating waves for each inverter, the open-end winding induction motor can be operated in the entire modulation range, eliminating all the 6n /spl plusmn/ 1 harmonics (n = 1, 3, 5, 7, etc.) coupled with 11th and 13th harmonic suppression. The proposed scheme also gives a smooth transition to the overmodulation region.     

Implementation of a Highly Reliable Hybrid Electric Scooter Drive

In contrast to hybrid electric cars (HECs), the issues concerning cost, volume, and reliability are even more rigorous when developing hybrid electric scooters (HESs). Therefore, the drive topology and control strategy used in HEC cannot be applied to HES directly. This paper presents a single-stage bidirectional dc/ac converter based on a general full-bridge inverter. The converter is designed for a low-voltage brushless dc motor/alternator (BLDCM/A) used in HESs, in which the additional bulky inductor and power switches are eliminated in the proposed design. In order to increase the reliability of the commutation process, a cost-effective sensorless control scheme for the motor and alternator commutation is developed. The commutation signals are extracted directly from the average terminal voltages, in which the motor neutral voltage, multistage analog Alters, analog-to-digital converters, and the complex digital phase-shift (delay) circuits are eliminated. In addition, instead of using the complex flux- weakening control technique, the winding-changeover technique is exploited to extend the range of the operating speed. With attractive features, such as low cost and ease of implementation, the proposed approach is particularly suitable for electric bikes, electric scooters, HESs, etc. Theoretical analysis and several experiments are conducted to justify the effectiveness of the proposed method.     

DC chopper with coupled-inductor commutation

A novel coupled-inductor commutation circuit is described. The circuit may also be used for inverters. It uses only two auxiliary thyristors, each operating in alternate cycles and eliminating the need for reversal of the commutating capacitor voltage. Trapped energy is fed back to the source. The output voltage is controllable from zero to the full input voltage. The commutation circuit can be connected to a voltage source other than that feeding the load. A DC chopper using this commutation scheme has been analysed and experimentally verified.     

浅谈锁相环电路中压控振荡器的分析与设计

本文先是进行了锁相环电路中LC压控振荡器的分析,然后进行了锁相环电路中压控振荡器的电路设计、相位噪声分析以及二次谐波滤波技术的应用,最后实际应用了设计的电路,并对应用的结果进行了分析.目的是为设计出性能更加优良的压控振荡器.     

基于直流无刷电机的太阳能水泵控制系统设计

基于无位置传感器永磁无刷直流电机设计了一款以STM32为主控芯片的太阳能水泵控制系统。主要介绍了硬件设计和软件设计两大部分,硬件设计包含开关逆变电路、驱动电路、电压检测电路等。软件设计包含主程序、自检程序、中断程序和故障保护程序流程。设计核心是采用MOS管内阻采样三相电流,并通过反电势过零检测法获取转子位置信号。在三相潜水泵上进行验证,相关试验波形图和数据验证了该系统硬件电路的可靠性以及软件程序架构的可行性。     

机械制冷机用直线电机驱动电路的谐波特性研究

对机械制冷机用直线电机驱动电路的谐波特性进行了研究。选择一台150 W的直线电机作为研究对象,通过理论仿真和实验验证进行了输出电压的谐波分析,探究了滤波器设计对驱动电路谐波特性的影响。通过研究滤波器电感L和电容C的变化与输出谐波的关系对滤波器进行了优化。经过优化的滤波器在性能上得到了很大的提升,输出驱动的谐波总畸变率(Total Harmonic Distortion, THD)从4%降到了1.96%。