Browsing by Author "Huang, Chih-Kai"

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BDCM Sensorless Control for Twelve-Step Square-Wave PWM
(2009)
Chen, Hung-Chi
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Huang, Chih-Kai
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Tsai, Tzu-Yang
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
After studying the development of BDCM sensorless control with six-step square-wave PWM (SWPWM) and six-step back-EMF detecting scheme (BEDS), the BDCM sensorless control with twelve-step SWPWM and twelve-step BEDS had been proposed and implemented in this paper. The proposed twelve-step BEDS generates the twelve commutation instants from six back-EMF zero-crossings during each cycle where the six-step BEDS generates the six commutation instants from six back-EMF zero-crossings. Since the analysis of six-step BEDS is helpful to develop the twelve-step BEDS, this paper studies the six-step SWPWM and six-step BEDS first and explains why some specific six-step SWPWM type is always used in the six-step BDCM sensorless control. Then, we obtain the specific twelve-step SWPWM types and develop the proposed twelve-step BEDS. From the simulated and experimental results, BDCM sensorless control with twelve-step SWPWM shows less current harmonics than that with six-step SWPWM.
Comparisons of Six-Step Square-Wave PWMs in Ultra-Low-Power SOC Integration
(2009)
Chen, Hung-Chi
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Tsai, Tzu-Yang
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Huang, Chih-Kai
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電控工程研究所
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Institute of Electrical and Control Engineering
It is well-known that ultra-low-power three-phase elements, such as ultra-small-size permanent-magnet brushless motor drivers, have been widely used in the consumer products. In order to reduce the cost, size and power consumption of products, it is necessary to integrate the system functions with square-wave PWM (SWPWM) driver in the system-on-chip (SOC) implementation. It follows that, the driver loss and loss distribution are the main challenges in the integration of ultra-low-power SWPWM driver where the driver loss include conducting loss, switching loss and gate driving loss, where the last one is often neglected in other low-, medium- and high-power drivers. On the other hand, there are 16 types and 64 types in 120-degree SWPWM and 180-degree SWPWM, respectively, and the resulting driver loss and loss distribution differ from each other. This paper studies the driver loss and loss distributions of all SWPWM types in detail. The result shows that SWPWM type-01_01, type-10_10 and type-010_010 are the recommended types in the SOC integration of ultra-low-power SWPWM driver.
Current sensorless control for single-phase boost-type SMR
(2008)
Chen, Hung-Chi
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Huang, Chih-Kai
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電控工程研究所
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Institute of Electrical and Control Engineering
In this paper, the single-loop current sensorless controls (SLCSC) for single-phase boost-type switching-mode-rectifiers (SMRs) are developed and digitally implemented in DSP-based system. Compared to the conventional multi-loop control with one inner current loop and one outer voltage loop, there is only one voltage loop in the proposed SLCSCs where its output is used to shift the nominal duty ratio pattern generated from the sensed input and output voltage. Because of no current loop, the efforts of sampling and tracking inductor current are unnecessary. It implies that the proposed SLCSCs are simple and very adaptable to the implementation with mixed-signal integrated circuits. It is also noted that the proposed SLCSCs are operated at continuous-current-mode (CCM). In this paper, first, the effects of shifting nominal duty ratio pattern on the input current waveform are analyzed and modeled with considering the inductor resistance and conduction voltages. It shows that the aligned current waveform can be inherently generated by the nominal duty ratio pattern and the current amplitude is roughly proportional to the shifting phase of nominal duty ratio pattern. Then, a voltage controller is included to regulate the dc output voltage by tuning this controllable phase. Finally, some simulated and experimental results have been given to demonstrate the performances of the proposed SLCSCs.
Phase feedforward control for single-phase boost-type SMR
(2008)
Chen, Hung-Chi
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Huang, Chih-Kai
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電控工程研究所
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Institute of Electrical and Control Engineering
In this paper, the phase feedforward control (PFFC) for single-phase boost-type switching-mode-rectifier (SMR) is proposed. Compared to the fixed feedforward signal in the conventional feedforward control, the phase of the conventional feedforward signal now is controllable according to the load power which makes PFFC be able to yield more feedforward efforts for high load power. For implementing the high-sampling-frequency function of power factor correction (PFC) in low-cost DSP-based system or in digital integrated circuit, the economical proportional-type (P-type) feedback controller is used in the proposed PFFC instead of using the proportional-plus-integral-type (PI-type) feedback controller or other complicated controllers. In addition, we can use relatively small P-type parameter in the proposed PFFC which also increases the system stability The analysis and design of proposed PFFC are described in detail. The simulation and experimental results also demonstrate the proposed PFFC. Target applications of the proposed PFFC are low-cost digital control for terrestrial 50-60Hz system whose performance is limited by the speed of the digital controller.
Position Sensorless BDCM Control with Repetitive Position-Dependent Load Torque
(2010)
Chen, Hung-Chi
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Huang, Chih-Kai
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This paper addresses the position sensorless control for brushless DC motor (BDCM) with repetitive position-dependent load torque which is a function of the absolute rotor position (not incremental rotor position). The robust sensorless control is composed of sensorless control and robust speed control. In order to commutate winding currents, the former one estimates the incremental rotor positions from the motor terminal voltages without any position sensor. In order to reduce the speed variations due to position-dependent load, a robust speed control is developed without estimating the absolute rotor position and other system parameter. In this paper, the effects of position-dependent load on the speed variations and the commutation intervals are studied in first. It shows that the position-dependent load can be estimated from the commutation intervals. Then, we develop the position sensorless control based on sensing terminal voltage from sensorless circuit and the robust speed control with adaptive gain. Finally, some simulated results have been given to demonstrate the robust performance of the proposed sensorless control for the position-dependent loads.
Robust BDCM sensorless control with position-dependent load torque
(2007)
Huang, Chih-Kai
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Yu, Pei-Yu
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Chen, Hung-Chi
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交大名義發表
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National Chiao Tung University
This paper presents the robust sensorless operation for brushless DC motors (BDCMs) loaded by the position-dependent load where the load torque is a function of the rotor angle (not electrical angle). Without any position sensor, the reliable position signals are generated from the motor terminal voltages through sensorless circuits. In order to reduce the speed variations especially in the low speed, an additional gain to adjust output voltage is included in the speed loop to compensate the repetitive position-dependent load. In first, the effects of position-dependent load on the speed variations and the commutation intervals are studied. It shows that we can estimate the position-dependent load from the commutation intervals. Then, we introduce the used sensorless scheme based on sensing terminal voltage. Finally, some simulated results have been given to demonstrate the robust performance of the proposed sensorless control for the position-dependent loads.