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Recently more attention has been paid to the distributed power systems due to their high flexibility and reliability. The high speed permanent magnet (PM) generator driven by micro-turbine has been widely investigated since it has small size, high efficiency and power density. The output high frequency AC power of the high speed PM generator needs to be converted into the AC power with constant frequency...
With the global environmental pollution and the increasing serious energy crisis today, photovoltaic (PV) power grid-connected generation system is becoming one of the most promising renewable energy technologies. However, the PV grid-connected power generation converter is not utilized at night. In order to improve the efficiency of photovoltaic (PV) power grid-connected generation system and improve...
The main advantages of the high speed machine are small size and high power density. However, the high speed machine suffers from higher loss density and cooling difficulty due to small cooling area, especially the high frequency harmonic currents produced by the power conversion system increase the loss and temperature of high speed machine. The output high frequency AC power of the high speed PM...
The main advantages of the high speed machine are small size and high power density. However, the high speed machine suffers from higher loss density and cooling difficulty due to small cooling area, especially the high frequency harmonic currents produced by the power conversion system increase the loss and temperature of high speed machine. The output high frequency AC power of the high speed PM...
Recently more attention has been paid to the distributed power systems due to their high flexibility and reliability. The high speed permanent magnet (PM) generator driven by micro-turbine has been widely investigated since it has small size, high efficiency and power density. Since the micro-turbine cannot be self started, the PM generator has to operate as a motor for the system staring, which needs...
Magnetic bearings can not only solve the bearing wear and life problems but also reduce the loss and noise of bearings. However, the strong non-linear and uncertainty of parameter of the magnetic bearings make the traditional PID controller difficult to ensure its long-term and stable operation. Based on the theory of quantitative feedback theory (QFT) and Hinfin control theory, this paper presents...
Recently more attention has been paid to the distributed power systems due to their high flexibility and reliability. The high speed permanent magnet (PM) generator driven by micro-turbine has been widely investigated since it has small size, high efficiency and power density. The output high frequency AC power of the high speed PM generator needs to be converted into the AC power with constant frequency...
Three-phase four-leg inverter has powerful ability to effectively treat unbalance and nonlinear loads, which outputs three phase symmetrical voltages. A novel control scheme with PD output voltage instantaneous-value feedback inner loop for voltage PID is proposed based on the model of three-phase four-leg inverter. The inner loop is designed to improve dynamic performance and the voltage external...
Using polyphase rectifier is an effective method to reduce harmonic components of current injected to the power supply for converter-fed power systems. A phase-shifting transformer is normally used for the phase-shifting. This paper presents an easy and economic way to eliminate the harmonic components in polyphase rectifying system by using the phase-shifting reactor instead of traditional phase-shifting...
The 3D finite element analysis (FEA) is used to establish the natural frequencies and vibration modes of the magnetic bearing-rotor system of high-speed machine and to define bearing stiffness of 3D-FEA model by exciting experiment. The critical speeds calculated by the method of FEA consistent with tested results of a high speed permanent magnet (PM). The study shows that the magnetic bearings introduce...
Recently more attention has been paid to the distributed power systems due to their high flexibility and reliability. The high speed permanent magnet (PM) generator driven by micro-turbine has been widely investigated since it has small size, high efficiency and power density. The output high frequency AC power of the high speed PM generator needs to be converted into the AC power with constant frequency...
Permanent magnet (PM) machine is especially being employed in high speed machines due to its simple structure and high power density. Nowadays, the sintered neodymium-iron-boron (Nd-Fe-B) material is used in most of PM machines. This kind of PM material has large compression strength but small tensile strength, and can not withstand the large centrifugal force due to the high rotation speed. A nonmagnetic...
High speed permanent magnet generator driven by micro-turbine has been widely investigated since it has small size, high efficiency and power density. The output high frequency AC power of the high speed PM generator needs to be converted into the AC power with constant frequency and voltage using AC/DC/AC converter. In order to reduce the current harmonics of high speed generator produced by the...
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