Xinda Song

Adaptive Compensation Method for High-Speed Surface PMSM Sensorless Drives of EMF-Based Position Estimation Error

To improve the performance of the surface permanent magnet synchronous motor drives, a sensorless control scheme based on the sliding-mode observer with an orthogonal phase-locked loop (PLL) incorporating two synchronous frequency-extract filters (SFFs) is proposed. The rotor position estimation errors are analyzed. The analysis results show that the harmonic errors of the estimated signal are hard to eliminate completely. Therefore, an improved adaptive notch filter - The SFF is proposed to extract the fundamental wave of the rotor position estimation before applying to the PLL. This method of the PLL combined SFFs can compensate the estimated back electromotive force harmonic error efficiently and adaptively. An experimental driveline system used for testing the electrical performance of the developed magnetically suspended motor is built. The effectiveness and the feasibility of the proposed method are validated with the experimental results.

Sensorless Drive for High-Speed Brushless DC Motor Based on the Virtual Neutral Voltage

The brushless dc (BLDC) motor can be driven by either pulse-width modulation (PWM) or pulse-amplitude modulation (PAM) techniques. Unfortunately, neither of them can be the most suitable method for the high-speed BLDC motor in the wide speed range, so a hybrid drive method combining PWM and PAM is first introduced. Then, this paper proposes a new sensorless control method based on the virtual neutral voltage for high-speed BLDC motor to suit for this hybrid drive method. In order to obtain the commutation signals from this seriously unclear voltage signal due to the commutation notches and electromagnetic interference, a low-pass filter with super low cutoff frequency is employed at the price of a large phase delay. Meanwhile, a novel sensorless control method based on the transition between “90-α” and “150-α” is introduced to handle the severe phase delay. At last, the feasibility and effectiveness of the proposed drive method and the sensorless control method are verified by several experiment results.

High-Precision Rotor Position Detection for High-Speed Surface PMSM Drive Based on Linear Hall-Effect Sensors

Accurate rotor position detection is essential for the surface permanent magnet synchronous motor (SPMSM) drive system to realize the stable and reliable operation. In this paper, two linear hall-effect sensors are utilized to detect the rotor position. However, the estimated errors in the measured signals, especially the harmonic components, impact on the accuracy of the rotor angle estimation significantly. For this reason, a high-precision rotor position detection method, which is based on the synchronous frequency extractors (SFEs) is presented. Two SFEs are used to filter out the high-order harmonics contained in the hall-effect signals. Further, the estimation of the rotor speed is used for the field-oriented control scheme of the PMSM. The proposed method is advantageous since it is simple, low cost, and high estimation accuracy. Finally, an experimental driveline system used for testing the electrical performance of developed high-speed magnetically suspended motor is built. The experimental results validate the feasibility and effectiveness of the proposed method in whole speed range.

Frequency-Varying Current Harmonics for Active Magnetic Bearing via Multiple Resonant Controllers

The rotating machinery suspended by an active magnetic bearing (AMB) system always suffers from rotor mass imbalance and sensor runout disturbances, which lead to the periodic fluctuations in control currents. This paper presents a novel multiple resonant controllers (MRC) for an AMB system to suppress the multifrequency current harmonics in the presence of variable rating speed. The principle and structure of the plug-in MRC used for current harmonics suppression in the AMB system is discussed. The design of the proposed MRC, using the progressively tuning and segmentation switch strategy, is given. The proposed design method for the MRC can achieve the balance between good stability and harmonics suppression precision. As well, the robustness of the overall system is systematically analyzed for the entire operational speed range. Simulation and experimental results for current fluctuations and multifrequency vibration forces on a magnetically suspended flywheel validate the effectiveness of the proposed method.

Sensorless Low-Current Start-Up Strategy of 100-kW BLDC Motor With Small Inductance

This paper focuses on the start-up strategy of a high-speed 100-kW brushless dc motor with small inductance using a voltage comparator. This paper includes three key technique contributions: 1) determining zero-speed positioning, 2) removing high-frequency disturbances, and 3) optimizing the controller parameters. The sensorless low-current start-up strategy is based on an amplification circuit: a low-pass filter circuit and a signal modulate circuit. The amplification circuit is used to amplify the amplitude of back electromotive force for detecting the rotor position at low speed, the low-pass filter circuit is used to remove high-frequency disturbances, and the signal modulate circuit is used to obtain the rotor position signal. A hysteresis control strategy is proposed against the load disturbance in the start-up stage. Experimental results show that the proposed sensorless start-up strategy can realize a low-current start-up.

High-Precision Sensorless Drive for High-Speed BLDC Motors Based on the Virtual Third Harmonic Back-EMF

In order to improve the performance of the high-speed brushless direct current motor drives, a novel high-precision sensorless drive has been developed. It is well known that the inevitable voltage pulses, which are generated during the commutation periods, will impact the rotor position detecting accuracy, and further impact the performance of the overall sensorless drive, especially in the higher speed range or under the heavier load conditions. For this reason, the active compensation method based on the virtual third harmonic back electromotive force incorporating the SFF-SOGI-PLL (synchronic-frequency filter incorporating the second-order generalized integrator based phase-locked loop) is proposed to precise detect the commutation points for sensorless drive. An experimental driveline system used for testing the electrical performance of the developed magnetically suspended motor is built. The mathematical analysis and the comparable experimental results have been shown to validate the effectiveness of the proposed sensorless drive algorithm.

Active Damping Stabilization for High-Speed BLDCM Drive System Based on Band-Pass Filter

The tight-speed regulation of the motor drive system can yield constant power load characteristics, which may lead to a negative admittance effect and destabilize the power supply. In order to overcome this problem, active damping compensation techniques have been widely used. However, the conventional active stabilization based on the low-pass filter combined with current reference injecting need a strong tradeoff between achieving effective active compensation and reducing the dynamic coupling. For this reason, a novel active damping compensation method based on the band-pass filter is proposed in this paper. The method is to feedback a portion of the dc-link voltage changes into the injecting nodes. Both the strategies of the current reference stage injecting and the voltage reference stage injecting have been analyzed. Simulation results show that the strategy of voltage reference injecting can avoid the coupling among system dynamics and the compensator. Finally, an experimental driveline platform based on the two identical high-speed magnetically suspended brushless DC motors coupling system is established. Experiential results verify the effectiveness of the proposed active stabilization method.

A Novel Sensorless Rotor Position Detection Method for High-Speed Surface PM Motors in a Wide Speed Range

In order to improve the performance of surface permanent magnet synchronous motor drives, a novel sensorless drive scheme is proposed in this paper, which is based on the virtual third-harmonic back EMF incorporating a fractional-N phase-locked loop (FN-PLL) and a synchronous frequency-extract filter (SFF). A simple low-pass filter based circuit is used to obtain the commutation points through the virtual third-harmonic back EMF. After that, an FN-PLL is applied to obtain continuous rotor position angles. On this basis, the SFF-based compensation is proposed to compensate the detecting error adaptively. Meanwhile, the field vector control loop for surface PM motor is proposed, which is based on the proposed rotor position detection link and compensation link. An experimental high-speed magnetically suspended blower platform is built. The effectiveness and the feasibility of the proposed method are validated with experimental results.