The present patent application relates to a method and equipment for eliminating harmonics based on two complementary techniques, namely the elimination of harmonics by selective harmonic elimination pulse-width modulation in conjunction with the multiple-wiring transformer. The association of these two resources is capable of reducing the harmonic distortion of currents to extremely low values, providing a truly unitary power factor. The technology is suitable for low and medium intensity alternating current—direct current and direct current—alternating current converters, which make interface with the electricity network and should have low harmonic distortion of the current because of the high power value involved, and also because of fragility of the electricity network (low power of short circuit at the coupling point).

A compensation filter and a method for activating a compensation filter are disclosed. In an embodiment a compensation filter includes an operational amplifier, a capacitive element, a first and a second resistive element and a current converter. The compensation filter is configured to attenuate a common mode interference in a critical frequency range.

The invention relates to an energy generating installation, especially a wind power station, comprising a drive shaft connected to a rotor (1), a generator (8) and a differential transmission (11 to 13) provided with three drives or outputs. A first drive is connected to the drive shaft, an output is connected to a generator (8), and a second drive is connected to an electrical differential drive (6, 14). The differential drive (6, 14) is connected to a network (10) by means of a frequency converter (7, 15) comprising an electrical energy accumulator in the direct-current intermediate circuit.

The principles described herein provide an electrical power supply system having circuitry that reduces the noise and interference of harmonic signals introduced by non-linear loads. In particular, one or more embodiments can include a power correction system that includes transformers and capacitors having parameters and configured to redirect harmonic energy in a power signal to deliver clean power to loads in a system. Additionally, the power correction system can mitigate negative effect of in-rush current passing through the electrical power supply system resulting in more efficient energy usage and reducing power failure of loads in the system. Moreover, the power correction system can include various additional features that facilitate convenient connection and/or disconnection of the power control system without disrupting the delivery of electrical power to loads in the system.

The present invention discloses a modular intelligent combined wind power converter and a control method thereof. The modular intelligent combined wind power converter comprises separate bridge arm power units, wherein a plurality of the bridge arm power units are connected in parallel to form a high-capacity bridge arm power module, three bridge arm power modules form a three-phase full-controlled bridge power module, and the three-phase full-controlled bridge power module comprises an electric reactor, a capacitor, a fuse and a circuit breaker to form a basic converter module, and the basic converter module forms a high-capacity wind power converter through a modular intelligent combination method.

An electric power control system includes: a bidirectional electric power converter including AC and DC terminals, the AC terminal being connected to an AC power system, the DC terminal being connected to a DC power system to which one or more DC power loads are connected, the bidirectional electric power converter mutually converting AC power of the AC power system and DC power of the DC power system; an electric power storage that is connected to the DC power system and stores electric power of the DC power system; and a bidirectional electric power conversion controller that performs first control of controlling an output or input of the AC terminal of the bidirectional electric power converter such that a charge current, discharge current, charge electric power, or discharge electric power of the electric power storage coincides with a predetermined target current value or a predetermined target electric power value.

Since inductance due to wiring to a Y capacitor is large, it is necessary to arrange the Y capacitor near a bus bar, and there is no degree of freedom in arranging the Y capacitor. Directions of currents flowing through a positive electrode side wiring 301 and a negative electrode side wiring 302 in a multi-core cable 300 are a direction 301a from a bus bar positive electrode terminal 114 toward the Y capacitor positive electrode terminal 201, and a direction 302b from a bus bar negative electrode terminal 115 toward the Y capacitor negative electrode terminal 202, respectively. On the other hand, a direction of a current flowing through a ground wiring 303 is a direction 302b from a Y capacitor ground terminal 203 toward a ground terminal 116. A magnetic flux generated by the currents flowing through the positive electrode side wiring 301 and the negative electrode side wiring 302 in the multi-core cable 300 and a magnetic flux generated by the current flowing through the ground wiring 303 in the multi-core cable 300 cancel each other out, and the inductance can be kept small.

An uninterruptible power supply (UPS) includes a rectifier circuit coupled to an AC input and configured to produce a DC voltage between first and second DC buses, an inverter circuit coupled to the first and second DC buses and configured to produce an AC voltage at the AC output. The UPS further includes an auxiliary power circuit comprising third and fourth DC buses configured to be coupled to a DC power source and third and fourth capacitors coupled between respective ones of the third and fourth DC buses and the neutral and respective first and second switches configured to couple and decouple respective ones of the third and fourth DC buses to and from respective ones of the first and second DC buses. The third and fourth capacitors may have capacitances greater than capacitances of the first and second capacitors.

A semiconductor switch includes a first switching element connected between a first terminal and a second terminal, a second switching element connected between the second terminal and a third terminal, a first resonant circuit having a zero impedance when resonating at a first frequency, a second resonant circuit having a zero impedance when resonating at N times the first frequency, wherein N is an integer greater than 1, and a transmission line having a first point connected to the second terminal, a second point connected to the first resonant circuit, and a third point connected to the second resonant circuit. A length of the transmission line between the first and second points corresponds to one-quarter of a wavelength corresponding to the first frequency, and a length of the transmission line between the first and third points corresponds to one-half of the wavelength corresponding to the first frequency divided by N.

A voltage stabilizing module for multi power source input is compatible with multiple input power sources including DC power source and/or AC power source and comprises a plurality of receiving ends, a power source selection unit and a voltage conversion unit. The receiving ends receive the input power sources. The power source selection unit is coupled with the receiving ends to receive the input power sources and sets at least one of the input power sources as a working power source. The voltage conversion unit receives the working power source and keeps the working power source at a working voltage level to act as a voltage signal outputted to a loading.