33results about How to "Guaranteed power factor" patented technology

The invention discloses a power factor correction control circuit for reducing EMI (electro magnetic interference), which comprises an inductive current threshold value, wherein when an inductive current is less than the inductive current threshold value, a peak value of the inductive current is controlled to be changed along with an input voltage; and when the inductive current reaches the inductive current threshold value, the inductive current is limited to be the inductive current threshold value. In such a way, the maximum peak of the inductive current is reduced, so that an inductive ripple current is reduced; the power factor is ensured, and the EMI of the circuit is reduced simultaneously, so that circuit filtering can be carried out simply and easily; and the power factor correction control circuit is extremely suitable for occasions with middle or low power. In addition, the peak current stress of the circuit is low, so that a switch tube and other components have small loss, and the utilization ratio of a power supply is further improved. The power factor correction control circuit for reducing the EMI disclosed by the invention meets the requirements of high-power factor and IEC61000-3-2 on the harmonic of the power supply, and has low cost and a small size.

The invention relates to a control device with a compensatory active PFC (power factor correction) and a control method thereof. The control device with the compensatory active PFC comprises an input rectifying unit circuit, a PFC unit circuit and a filtering energy storage unit circuit which are sequentially connected, wherein an input voltage sampling circuit is connected with the output of the input rectifying unit circuit in parallel; a load current sampling circuit is connected between the PFC unit circuit and the input rectifying unit circuit in series; a voltage sampling unit circuit of PFC output voltage is connected with the filtering energy storage unit circuit in parallel; a PFC driving circuit is connected with the PFC unit circuit; a main control unit (MCU) is respectively connected with the input voltage sampling circuit, the PFC driving circuit and the voltage sampling unit circuit; and the MCU comprises any one or a combination of more than two of a voltage compensation correction factor module, a load current correction factor module and a compressor parameter correction module. The invention has the characteristics of flexible operation and reduction of interference, loss and cost.

The invention relates to a power supply system without passing neutral phases in the whole journey of a high-speed passenger transport line electric multiple units (EMU), and belongs to the field of power supply of high-speed EMU. A cantilever at the upper end of an anchoring section pillar is provided with two catenary wires, the catenary wires are connected with droppers, the droppers are connected with a single-phase alpha contact line and a single-phase beta contact line which are output from the secondary side of a traction transformer, the single-phase alpha and the single-phase beta are parallel, are insulated with each other, are input into the internal power supply system of the EMU through double-phase pantographs and are connected with a basic power supply unit TUB1 and a basic power supply unit TUB2 respectively, and the basic power supply unit TUB1 and the basic power supply unit TUB2 are separate with each other. No circuit breaker switch or neutral insulating section is needed to be arranged on the single-phase alpha and the single-phase beta, and no negative-sequence current generates in a three-phase high-voltage supply network. The invention further provides a circuit structure used for improving a CRH1-model 8-compartment EMU and a CRH5-model 8-compartment EMU into a 6-compartment EMU, a 10-compartment EMU, a 12-compartment EMU and a 16-compartment EMU recombined by two 8-compartment EMUs and for brake regenerative braking.

This invention discloses a vector control system for a permanent magnet synchronous motor including a primary power circuit of a matrix converter, a matrix converter controller, an input filter and a voltage test circuit in the following principle: the double space vector modulation of the matrix converter is to turn the converter equivalent to a AC-DC conversion part and a DC-AC conversion part with virtual DC, actually, the space vector control is carried out to the input current and output voltage. Advantage: 1, a double-space modulation strategy is applied to the matrix converter, which either guarantees the power factor at the network side or realizes AC-AC conversion directly to avoid the middle DC part and reduce its volume, 2, double-way flow is realized to energy of the converter to realize four quadrant work of magnet synchronous motor, 3, small volume and low cost.

The invention relates to a fan cooling control device which comprises a temperature detection sensor, a plurality of fans and a PLC (Programmable Logic Controller) module which is connected with the temperature detection sensor and is suitable for controlling working of the fans with the corresponding number and corresponding rotational speeds of the fans according to the external temperature. According to the fan cooling control device disclosed by the invention, the traditional relay circuit is replaced by the PLC module, so that the defects of tedious wiring and high failure rate of relays are avoided; and the fan number and the rotation number are controlled according to the temperature, the fans do not need to started or a few fans are started with low revolution in winter with lower temperature, while all the fans need to be started in summer with high temperature, and the revolution is increased according to the specific temperature, so that a great deal of power is saved, and the service life of a motor is also prolonged.

The invention discloses a harmonic wave reactive compensation control method based on a high-voltage inverter bypass. A high-voltage inverter failure bypass reactive compensation circuit comprises an inverter, wherein the inverter is connected with a power grid through an wire inlet switch; a wire outlet end of the inverter is connected to a motor through a three-phase reactor and a wire outlet switch sequentially; a wire inlet end of a bypass switch is connected with a wire inlet end of an inverter wire inlet switch; and a wire outlet end of the bypass switch is connected with a wire outlet end of an inverter wire outlet switch. By the harmonic wave reactive compensation control method based on the high-voltage inverter bypass, a high-voltage inverter device can perform reactive compensation in real time according to motor load after the high-voltage inverter automatically switches the failure into the power frequency to operate, the network side power factor is increased, and the quality of electric energy is improved, so that the utilization ratio of the inverter is increased to the maximum degree and the benefit maximization of users is guaranteed.

The invention discloses an alternating current-direct current (AC-DC) converter which comprises a converter based on a three-phase thyristor, a full-bridge converter based on a simplified insulated gate bipolar transistor (IGBT) and an inductor connected between the converter and the full-bridge converter, wherein in a driving mode, the converter based on the three-phase thyristor works in an AC-DC rectifier mode, and the full-bridge converter based on the simplified IGBT works in a boost chopper circuit mode and controls the inductor to suppress current harmonics of the power supply network so as to increase the power factor; and in a regenerative braking mode, the converter based on the three-phase thyristor feeds the regenerated energy back to the power supply system so as to realize energy recovery. The invention also discloses a frequency converter. By using the scheme, the power factor can be increased, energy recovery can be realized, and the implementation cost is low.

The invention relates to a controller of a production clearance reactive power compensation device of power supply and distribution systems of a small steel rolling workshop, which belongs to the field of electrical control. The controller comprises a busbar electricity total current signal collector of the power distribution system, a reactive power detection control board (3) of an upper-level network, a rectifier transformer secondary side TSC device control board (4) of the power supply system, a rectifier transformer secondary side controller (5) of the power supply system and a capacitance compensation switching controller (6). The small steel rolling workshop arranges a high-voltage control cabinet at a 10kV busbar, electrical parameters of the 10kV busbar are collected through a voltage and current detection element and a programmable controller, a mathematical model is used for calculation, and communication with a TSC device hung on the secondary side of a rectifier transformer below each section of the busbar is carried out through a network, thereby emitting a capacitor switching control command, carrying out dynamic compensation on reactive power of a power grid, improving power factor of the power supply system under the working condition that a bar production line does not roll steel, ensuring that the power factor of the power supply system achieves the relevant national standards and effectively saving power energy.

The invention discloses a novel fixed reactive compensation device. The novel fixed reactive compensation device comprises a voltage transformer, a current transformer, an analog-digital converter, a controllable switch, a digital signal processor, human-machine interaction equipment and a conventional fixed reactive compensation device, wherein the voltage transformer and the current transformer are used for measuring three-phase network voltage and current analog signals in real time; the analog-digital converter is connected with the voltage transformer and the current transformer; the controllable switch is connected onto a main incoming line of all capacitor branch lines in the conventional fixed reactive compensation device; the digital signal processor is used for carrying out reactive tide comprehensive information analysis according to network voltage and current digital signals so as to identify a reactive tide direction and control the human-machine equipment to display reactive tide comprehensive information in real time; when reactive power is sent back to a power grid, the controllable switch is controlled to be disconnected, so that the requirements of reaching the standard of power factors and not sending the reactive power back to the power grid are met by simply modifying the conventional fixed reactive compensation device, and the economical burden of enterprise users is alleviated.

The invention relates to a large combined cycle set before-separation automatic idle work reducing method and a control device. The method is characterized in that a distributed control system (DCS) is used for detecting the working state of a set, and by controlling exciting currents through an excitation system of the set, the fact that large combined cycle set before-separation idle work is reduced to a target value automatically is achieved. The structure is characterized in that the DCS, a detecting loop and a generator excitation controller AVR are included, the detecting loop is provided with a halt signal detecting end, a generator power utilization end voltage detecting end, an active power detecting end and an idle work detecting end, an output end of the detecting loop is connected with an input end of the DCS, an output end of the DCS is connected with a control input end of the generator excitation controller AVR, and an output end of the generator excitation controller AVR is connected with an input end of the excitation system of the generator set. The large combined cycle set before-separation automatic idle work reducing method and the control device have the advantages that voltage fluctuation caused by the fact that work conditions are changed suddenly, voltages at the generator end can jump because of separation, and a power grid gets rid of a large amount of idle work suddenly can be avoided.

The invention discloses a high-voltage driving power supply for a high-energy ion air purifier. The high-voltage driving power supply comprises a voltage-stabilizing frequency converter and a low-frequency boosting transformer that are connected successively. The voltage-stabilizing frequency converter provides a low-frequency alternating-current power supply with the adjustable voltage and frequency for the low-frequency boosting transformer based on purification needs. The low-frequency boosting transformer is used for realizing boosting on the low-frequency alternating-current power supply.The voltage-stabilizing frequency converter consists of a voltage-regulation frequency-modulation module, a control module, a voltage detection module and a current detection module. The output voltage from the high-voltage driving power supply is tracked and given and can be adjusted and thus the high-energy ion energy excited by a high-energy ionizer is higher than the chemical bond energy of gas needing to be purified, so that the chemical bond is broken. The output frequency of the high-voltage driving power supply is determined based on the purification frequency and the ozone concentration, so that the purification efficiency of the high-energy ionizer for gas with different chemical compositions is guaranteed and the concentration of the generated ozone is controlled effectively.

The invention discloses a high-voltage power distribution network reactive power planning method for preventing capacitive reactive power reverse transmission. According to the method, a comprehensive reactive power planning model which comprises a reactor and a capacitor and considers power factor constraints is built; according to the model, the simultaneous configuration of the capacitor and the reactor in a high-voltage power distribution system is considered, a minimum sum of reactive compensation equipment investment and active power loss cost in a planning period is taken as an objective function, node power factor constraints are added in the constraints; an improved genetic algorithm based on power factor reactive sensitivity is proposed; and the proposed model is solved, so thata capacitor and reactor reactive planning scheme is obtained; time-sharing switching is carried out in peak and valley periods, the power factor constraints can be met, capacitive reactive power is prevented from being reversely transmitted to a superior power grid; and the problems of reactive power reverse transmission and power factor out-of-limit occur when the high-voltage power distribution network with the peak and valley difference increasing day by day is in low load are solved.