Abstract: Provided is a wind power generation apparatus to which general purpose inverters are applicable. An inverter in a constant-voltage mode is used. While a wind power generator is generating electricity, switching circuits are turned on and off at a controlled duty cycles to intermittently short-circuit an armature winding, boosting the voltage and controlling the rotational speed of a windmill rotating blade, with the result that the voltage applied to the inverter is made constant. At the activation, in order to prevent an excessive voltage from being generated while an inverter is changing from the stand-by state to the activated state, ON/OFF control of a switching circuit is performed to switch between the output voltage of a rectifier and the voltage generated at a resistor, with the result that the voltage is controlled and maintained at an appropriate value.

Abstract: Provided is a wind power generation apparatus to which general purpose inverters are applicable. An inverter in a constant-voltage mode is used. While a wind power generator is generating electricity, switching circuits are turned on and off at a controlled duty cycles to intermittently short-circuit an armature winding, boosting the voltage and controlling the rotational speed of a windmill rotating blade, with the result that the voltage applied to the inverter is made constant. At the activation, in order to prevent an excessive voltage from being generated while an inverter is changing from the stand-by state to the activated state, ON/OFF control of a switching circuit is performed to switch between the output voltage of a rectifier and the voltage generated at a resistor, with the result that the voltage is controlled and maintained at an appropriate value.

Abstract: A wind power generation control device which controls a wind power generator using a wind turbine blade having a fixed pitch angle is provided.

Abstract: A data decoding system for decoding a digital signal stored on a magnetic medium so that one of logical variables "1" and "0" is indicated by a state inversion of signals "H" and "L" at a time interval of a bit cell period, while the other logical variable is indicated by the state inversion at a time interval of half of the bit cell period, wherein a reproduction processing signal is produced having the signal state varying only in response to the state inversion corresponding to one of the logical variables and an NRZ signal is formed by exclusive logical addition of the reproduction processing signal and a delay signal delaying the reproduction processing signal for a time interval of one bit cell period.

Abstract: A differential amplifier able to produce differential-mode output signals different from one another in DC voltage level, is formed by connecting a pair of NPN transistors and another pair of PNP transistors so that the emitter electrodes of these four transistors are coupled to one another by a resistive coupling circuit. The resistive coupling circuit is so arranged that the resistance between the emitter electrodes of the NPN transistors is equal to that between the emitter electrodes of the PNP transistors, with the resistances between the emitter electrodes of one of the NPN transistors and of one of the PNP transistors being equal to that between the emitter electrodes of the other NPN transistor and the other PNP transistor.