For the problem of higher transverse sensitivity ratio of the cymbal piezoelectric vibration acceleration sensors, a mathematical model of output voltage sensitivity is established which employ orthogonal and array methods to reduce the transverse sensitivity ratio of the piezoelectric vibration acceleration sensor. Two compensation methods are designed. The results showed that the array and orthogonal methods can decrease the effect of the transverse interference of acceleration sensor effectively and control the relative error in a smaller range, improve the measurement accuracy of the sensors.

Developing effective black start plans is significant to the rapid restoration from the power system blackout. This paper makes theoretical research in some key concerns of self-excitation, over-voltage, the impact of starting loads on the voltage and frequency, and stability of the initial small system. The paper also presents countermeasures against these problems. This overview should be very useful to utility operators involved in the development of black start plans.

Because the nonlinear and strong coupling characteristics of brushless DC motor, the classical PI controller can not control it easily. In order to solve the control problem of brushless DC motor, an improved control method is proposed which based on passivity-based control technology. According to a model of brushless DC motor (BLDCM) that based on Euler －Lagrange (EL) equation, designed a passivity-based controller. The simulation result shows that，compared with the PI controller，this method can not only improve the dynamic response property and anti-jamming ability of the system, but also get a better speed-adjustability.