51results about How to "Solve the circulation problem" patented technology

The invention discloses a seamless and circulation-less switching system for two groups of DC (direct current) power supplies. The system comprises an anode port and a cathode port which are connected with electrical equipment, a first branch connected with a first DC power supply, a second branch connected with a second DC power supply, a switching circuit, a voltage sampling circuit, a current sampling circuit and a control module, wherein the switching circuit comprises a first switch, a second switch, a third switch and a fourth switch; the first switch and the second switch are connectedin the first branch and the second branch respectively and composed of DC contactors; the third switch and the fourth switch are composed of controllable electronic switch devices; and the third switch and the fourth switch are connected in parallel with the first switch and the second switch respectively. The system adopts DC contactors for switching and one-way conducting controllable electronic switch devices for compensation; in the automatic switching process of the DC power supplies, the problems of circulation and output power down in the switching of the DC power supplies can be effectively solved, and the seamless and circulation-less switching among the DC power supplies is realized; and the system has the characteristics of simple and novel structure and reliable performance.

The invention discloses a controller of an energy feed device, the controller of the energy feed device is used to control the magnitude and direction of the transmission power of a regenerative electric energy feedback device; the controller of the energy feed device includes: an analog quantity input unit, a reactive power calculation unit ; The analog input unit is used to obtain the AC bus voltage of the traction station, the incoming line current of the traction station, the AC bus voltage of the main station, and the incoming line current of the main station; the reactive power calculation unit, according to the power factor target of the traction station Value output corresponding reactive power to compensate the power factor of the traction station; or, with the goal of improving the power factor of the main station, control the regenerative power feedback device to output a given reactive power. The present invention also provides a rail transit traction power supply system and a method for suppressing circulation of the system. By adjusting the output reactive power of the regenerative power feedback device, the AC output voltage of the regenerative power feedback device is stabilized, and the generation between the regenerative power feedback device and the traction rectifier is avoided. circulation.

The embodiment of the present invention discloses a novel zero-voltage switching full-bridge direct current converter, and its specific composition includes first to fourth switch tubes, first and second capacitors, first to sixth rectifier diodes, first and second 2. Isolation transformer, which also includes DC power supply, filter inductor and load resistance. This DC converter effectively solves the problems of narrow zero-voltage switching range of switching tube, primary side circulation loss, and rectified voltage oscillation, which are common in existing full-bridge converters. . The invention has the advantages of simple circuit structure, wide soft switching range, low output current ripple, high conversion efficiency and the like.

A compound circulation suppression method and device for a shore power supply system can solve the circulation problem in a parallel system of shore power supply. The compound circulation suppression method includes a circulation suppression method based on the combination of average current control and centralized control, which controls the amplitude, frequency and phase of the shore power supply output voltage through the control method of current sharing during the control process; centralized control By coordinating the controllers, the modulation waves of the dq coordinate system are uniformly generated and sent to the central controllers of each variable frequency power supply, and each central controller receives the dq axis modulation waves U md , U mq After dividing by the average value of the DC bus voltage of each variable frequency power supply, it is superimposed with the compensation amount generated by the current sharing control to achieve the purpose of suppressing the circulation of the parallel shore power system. The stable operation of the shore power supply system is guaranteed, and the invention is simple to implement, and has the advantages of low cost, high reliability, easy capacity expansion, and the like.