70results about How to "Improve current waveform" patented technology

The invention carries out field weakening control on a brushless motor without use of preset controlled variables, such as table values, and independently of the input voltage of an inverter circuit 3 in a motor driving device that drives the brushless motor. The motor driving device comprises an inverter circuit 3 that converts the output voltage of a voltage source 1 into a three-phase alternating current, and outputs it to a motor 2; a rotor position estimating unit 5 that estimates the rotor position of the brushless motor; and an inverter control unit 4a that controls the inverter circuit 3 so that the brushless motor is driven by a current based on the estimated rotor position. The inverter control unit 4a determines a value [beta] of advance angle, which is the advance angle of a current supplied to the brushless motor relative to the estimated rotor position, so that the difference between commanded number of revolutions fo and actual number of revolutions f is minimized.

The invention suppresses the degradation of an input power factor or drive efficiency which is caused by the distortion of a current waveform flowing to a single-phase AC power source under the effect of a regenerative current from a motor 2 or a charging current to internal parasitic capacitance, related to a motor driver 101b of inverter driving that comprises no large capacitance capacitor.The motor driver comprises a single-phase rectification circuit 3 connected to a single-phase AC power source 1, an inverter circuit 4 which is connected to the single-phase rectification circuit 3 and applies a current and a voltage to a motor 2, and an inverter control unit 5b that controls the inverter circuit 4. The inverter control unit 5b controls the current supplied to a motor 2 which is the output of the inverter circuit 4, so that an inverter input voltage Vpn comes to be equal to an absolute value 3 / 4 v 3 / 4 of the voltage of the single-phase AC power source 1.

The invention relates to a wind power generator, in particular to a hybrid-excited brushless DC wind power generator, which solves a problem that a conventional brushless DC generator cannot be suitable for wind power generation due to excitation or reasonable structure for supplying excitation current. The wind power generator comprises a stator, a DC motor armature winding, a rotation shaft, and a main excitation permanent magnet pole and an auxiliary electromagnetic pole both arranged on the rotation shaft, as well as an excitation current supply unit of the auxiliary excitation electromagnetic pole, wherein the excitation current supply unit of the auxiliary excitation electromagnetic pole consists of a ring-shaped DC exciter and an excitation current providing unit of the ring-shaped DC exciter; the ring-shaped DC exciter consists of a ring-shaped rotor and DC excitation regulators both fixed on the rotating shaft; and each DC excitation regulator consists of a U-shaped iron core and an excitation coil wound thereon. The wind power generator is applicable to wind parks with larger area and wind farms where a plurality of wind power generators synchronously operate, and also can be taken as a motor used in high power and multiple variable-speed engineering equipment capable of regulating output moment.