Our motto
Nothing worthwhile is easy. Attempt the impossible, work hard, play hard, do experiments, fail fast, fail smart, do experiments. Eventually we'll create --- hopefully something worthwhile.
Power Electronic Converter
(電力電子轉換器設計)
We have designed various power converters for industrial applications, among them including Buck converters, Boost converters, VRM, Flyback converters, SEPIC, PFC Rectifiers, and Inverters. One essential design problem about these high-efficiency switching power converters is how to eliminate unwanted noise and distortion that arise from switching of power transistors. We have developed several effective feedback modulation and control schemes for this purpose, among them including Feedback Dithering Modulation and Sliding Mode Modulation, which have been proved effective in eliminating noise and distortion in the frequency band of interest.
Variable Frequency Compressor Drive（無感測變頻壓縮機驅動設計）
Several control, modulation, and signal processing techniques have been utilized in the design of the driving circuit for sensorless permanent magnetic synchronous motors in rotary compressors. The driving circuit mainly consists of a PFC Rectifier, an IPM inverter, and a DSP. Special emphasis has been put in the designs of algorithms for 1) real-time motor position and speed estimation, and unbalanced load estimation, 2) minimum-loss current control for raising power efficiency, 3) weak flux control for extending the motor speed range, and 4) unbalanced load compensation for reducing vibration and acoustic noise.
Class-D Audio Power Amplifier
(高效率低失真音響擴大機設計)
As compared with conventional class-A and class-AB power amplifiers, class-D power amplifiers have much less power loss and smaller size. This nice property conforms to the global trend of reducing carbon footprint. An audio power amplifier has a huge effect on how your speaker sounds. The design objective of the class-D audio amplifier is quite similar to that of power converter design but more challenging, because sensitive Human ear simply cannot stand beautiful music coming with a bit of noise. We have developed an optimal multi-loop feedback controller to faithfully produce the driving current according to the audio input signal while eliminating noise and harmonics. This multi-loop and driving-current feedback design makes the power amplifier have predictable high performance, without much being degraded by device or circuit nonidealities.
Active Noise Cancellation Headphone（主動式消音耳機）
We developed a practical method of designing controllers for active noise cancellation headphones. Without attempting system identification, the headphone dynamics is directly described by a set of frequency-response data. In frequency domain, the controller synthesis problem is formulated as a constrained optimization problem, where the H2 performance objective is minimized with various frequency-dependent constraints. The fixed-order robust controller is thus designed to achieve maximum noise attenuation with acceptable stability margins.
Ultrasonic Transducer Drive
（超音波換能器驅動電路設計）
Ultrasonic transducers, devices that convert electrical energy to ultrasonic vibrations, find their way into a wide spectrum of applications, including ultrasonic spray coating, ultrasonic assisted machining, ultrasonic cleaning, ultrasonic welding, and many more. Ultrasonic transducers are commonly designed to have high Q-factors in order to achieve high efficiency. For a high Q-factor transducer, however, a slight deviation from the transducer's resonant frequency may quench the oscillation and cause a serious drop in transducer efficiency. We have designed a resonant frequency tracking power amplifier that is capable of detecting and tracking the resonance of an ultrasonic transducer and automatically drive the transducer right at its resonance.
High-Precision Temperature Control
（工業冷卻機與直流變頻冷暖氣溫度控制）
The precision of machining of a CNC machine tool depends largely on the precision of temperature control of its cooling system. The nonlinearity, uncertainty, delay and large thermal load fluctuations make the design of the temperature controller difficult. We have designed a high-precision self-tuning temperature controller suitable for various industrial cooling machines. The proposed controller features automatic detection and tuning of its parameters according to the dynamics of the cooling system, thereby better adapting to different cooling systems and achieving higher temperature precision. We focused on the development of three key techniques for high-precision temperature control: self tuning, nonlinearity compensation, dynamic thermal load compensation.