Kai-chao Yao

Direct Torque Control for a Matrix Converter Based on Induction Motor Drive Systems

The paper proposes a direct torque control (DTC) scheme for a matrix-converter-fed induction motor drive system. DTC is a high performance motor control scheme with fast torque and flux responses. However, the main disadvantage of conventional DTC is electromagnetic torque ripple. Besides, the matrix converter is a single-stage ac-ac power conversion device without dc-link energy storage elements. Due to the properties of the matrix converter, the pseudo dc-link will provide with three different types of voltage: the high, middle, and low voltages. Therefore, based on space vector modulation generated by a matrix converter, there are three states on each space vector location. By suitably selecting switching pattern, the electromagnetic torque ripple of the motor is effectively reduced. Using this switching strategy, the advantages of the DTC schemes and the benefits of the matrix converters can be combined. As a result, a satisfactory servo drive can be achieved.

Digital Control Design of Decentralized Stochastic Singularly-Perturbed Large-Scale Actuator Type Systems with Multiple Time-Varying Delays

This paper develops an optimal robust control algorithm for finding digital computer control of decentralized stochastic singularly-perturbed large-scale actuator type systems with multiple time varying delays. Due to the derived algorithm concerns at each moment, the found controller is also suitable in the time varying condition. Moreover, this system possesses the fast response characteristics of the subsystems. The system order can be reduced and the analysis process can be simplified. . This noise-disturbed, time varying and multiple delay system can be often seen in practical computer controlled large-scale systems such as electric power systems, communication networks, cyber networks, and aerospace systems. Finally, the optimal cost is also obtained.

Virtual Impedance Analyzer Design and Implementation

In this research, the structure and design of virtual impedance analyzers are studied. The construction process is also described and introduced. This programmable virtual impedance analyzer is achieved by software part, Labview, hardware part, DAQ card and some external circuits. The measurement functions include: (1) impedance [Z] display that has magnitude, phase, impedance and reactance, (2) display settings that has visible section and scale, (3) measurement frequency control, (4) run button, and (5) display window. In the illustrations, demonstrate the design of front panels and also proceed the measurement test of designed virtual impedance analyzer to show the capabilities.

Frequency Scaling of Adaptive Digital Filter Design by Poleplacement Technique

This research proposes using poleplacement technique to achieve adaptive filter design. Digital control concept is also deployed in the design scheme for practical computer control use. Frequency scaling is current well known skill to scale low-pass prototype filter into another low-pass filter. It is a mathematical methodology to have the passband change. Here, poleplacement approach is used to shift poles of the original low-pass prototype filter to the desired poles location so that a new filter which has the desired passband and the desired cut-off frequency can be obtained. This approach potentially makes filters possess adaptive performances, and the filter system can be controlled by digital computer. The responses of the frequency transformed filters and the responses of the state feedback digital controlled filters are also compared to show the feasibility of this approach in this paper

Developing an industry-oriented safety curriculum using the Delphi technique

In this study, we examined the development of industry-oriented safety degree curricula at a college level. Based on a review of literature on the practices and study of the development of safety curricula, we classified occupational safety and health curricula into the following three domains: safety engineering, health engineering, and safety and health management. We invited 44 safety professionals to complete a four-round survey that was designed using a modified Delphi technique. We used Chi-square statistics to test the panel experts’ consensus on the significance of the items in the three domains and employed descriptive statistics to rank the participants’ rating of each item. The results showed that the top three items for each of the three domains were Risk Assessment, Dangerous Machinery and Equipment, and Fire and Explosion Prevention for safety engineering; Ergonomics, Industrial Toxicology, and Health Risk Assessment for health engineering; and Industrial Safety and Health Regulations, Accident Investigation and Analysis, and Emergency Response for safety and health management. Only graduates from safety programmes who possess practical industry-oriented abilities can satisfy industry demands and provide value to the existence of college safety programmes.

A Fast way to Design Adaptive Digital High-pass Filters

This is an extension research of [1]. In [1], frequency scaling of adaptive digital filter design algorithm is proposed. The pole placement technique is used to achieve the frequency scaling of adaptive digital filter design. In this paper, the same concept is applied for a fast way to design adaptive high-pass filters. Frequency transformation is used to transfer low-pass prototype filter into high-pass filter. State feedback is used to shift poles of the original low-pass prototype filter to the desired poles location so that a high-pass filter which has the desired passband and the desired cut-off frequency can be obtained. The responses of the frequency transformed high-pass filters and the responses of the state feedback digital controlled high-pass filters are also compared to show the feasibility of this approach in this paper.

Design and Implementation of Control Systems Single Input Virtual Digital Multi-meter Design and Implementation

In this research, a single input virtual digital multi-meter are designed and constructed. It consists of three major works: (1) software design of front panel, (2) measurement circuit design and (3) system integration. The related measurement theories are also described and introduced. This digital multi-meter is made by software part, Labview, hardware part, DAQ card and external measurement circuits. The measurement functions include (1) DC voltage (2) AC voltage (3) DC current (4) AC current (5) resistance (6) capacitance (7) inductance (8) diode test (9) audio continuity. In the illustrations, demonstrate the design of front panels and also proceed the measurement test of the designed single input virtual digital multi-meter to show the capabilities.

An Iteration Method to Sub-optimal Output Feedback Computer Control of Decentralized Singularly-perturbed Systems

An iteration method is proposed for sub-optimal output feedback computer control of decentralized singularly-perturbed systems. Computer control, decentralized output feedback control, and order- reduced control are three primary goals for this control scheme. The analog to digital transformation technique is used to convert continuous-time state models to discrete-time domain for the controllers which can be implemented by computer and be able to deal with todays complicated large scale system. Singular perturbation methods are applied to reduce the order of the system. After order reduction, it will help us to analysis the system; reduce the manufacturing process and cost. The contribution of this research provides a sub-optimal computer control algorithm for large-scale and high-dimension systems with strong potential for practical applications, such as power distribution and communication networks.

Multi-Function Electro-Cardiogram Measurement System Design and Implementation

In this research, a multi-function electro-cardiogram measurement system is designed and constructed. The system applies the structure of virtual instrument built by software part, Labview hardware part, DAQ card and some external circuits is applied in the development process. This research integrates different fields that include physiological signals, circuits, virtual instrument, and physiology. The functions of system include waveform display, auto signal processing, data saving, histogram display, heartbeat display, irregular heart rhythms warning and remote measurement. Practical measurements have been carried out to demonstrate the capabilities of this measurement technique.

Adaptive Control Design of Band-Pass Digital Filters by Poleplacement Approach

This research proposes poleplacement approach to achieve adaptive control design of band-pass digital filters. Digital control concept is deployed in the design scheme for practical computer control use. Frequency transformation is current well known skill to transfer low-pass prototype filter into another desired filter. It is a mathematical methodology to have the passband change. Here, poleplacement approach is used to shift poles of the original low-pass prototype filter to the desired poles location so that a new filter which has the desired passband and the desired cut-off frequency can be obtained. This control process provides the filters potentially possessing adaptive performances. The filter responses of frequency transformation and the responses of poleplacement control approach are also compared to show the feasibility of this design. Key words: adaptive, digital, band-pass filter, control design, poleplacement.