35results about How to "Good overvoltage protection" patented technology

A wind turbine comprises a wind rotor, a generator driven by the wind rotor, a converter, wherein the generator and the converter generate electrical energy output via a connecting line with an inductively acting line reactor to a grid, and an overvoltage protection device comprising a plurality of different active modules, which are designed in such a way that they each effect, in different ways, a reduction in the voltage at the output of the converter, a switching matrix, which connects and disconnects the different active modules, and a selector comprising an overvoltage classifier, which is designed to select a predetermined stage depending on the overvoltage and to actuate the switching matrix in such a way that successive ones of the active modules are disconnected, wherein the overvoltage classifier defines a plurality of overvoltage ranges by virtue of in each case the selector setting different switching groups.

A power transmitter (101) of a wireless power transfer system comprises a resonance including a transmitter coil (103) for generating a power transfer signal for wirelessly transferring power to a power receiver (105). Further, a driver (1303) generates a drive signal for the resonance circuit (201) and a message receiver (1305) is arranged to receive messages from the power receiver (105). A power loop controller (1307) implements a power control loop by adapting the power of the drive signal in response to power control messages received from the power receiver (105). However, the regulation is subject to a constraint of at least one of a current or voltage of the resonance circuit and a power of the drive signal being below a maximum limit. Further, the power transmitter (101) comprises an adapter (1309) which adapts the maximum limit in response to a load indication indicative of a loading of the power transfer signal by the power receiver (105).

An overvoltage protection circuit may include a reference voltage generator, a trigger circuit, and a clamping device. The reference voltage generator is for providing a reference voltage that is relatively constant during a powered EOS/ESD event. The trigger circuit is coupled to receive the reference voltage and a power supply voltage. The trigger circuit is for comparing the reference voltage to the power supply voltage. In response to detecting that the power supply voltage is above the reference voltage, the trigger circuit provides a trigger signal having a voltage proportional to a voltage level of the overvoltage event. The clamping device is coupled between a first power supply terminal and a second power supply terminal. The clamping device is for providing a current path between the first and second power supply terminals in response to the trigger signal.

The invention discloses a permanent magnet synchronous motor (PMSM) closed-loop control system that comprises a main control board module and a driver board module. The main control board module is used for issuing instructions and processing various faults, and comprises an MCU minimum system with a STM32F103ZET6 as a core, a switching power supply module, a TFT color display module, a key module, a speed control module, a peripheral circuit module and a photoelectric isolation module. The whole closed-loop control system has good signal isolation, overvoltage protection, undervoltage protection, overcurrent protection and over-temperature detection circuits, and has high reliability. The hardware schematic of the system is designed and made into a PCB. A test result shows that the system can control the operation of the PMSM well. In software, the processor of the system is provided with a PMSM control library function and is short in development cycle. In hardware, the system is low in cost, complete in function and high in reliability. The system has a high application and promotion value.

The invention discloses a stepless speed regulating energy-saving hydraulic system for a cleaning sweeper truck. A proportional flow control valve is disposed on a pipeline before a hydraulic motor unit. The proportional flow control valve is provided with an oil inlet, a flow control oil outlet, and a bypass oil leaking opening. The invention is advantageous in that through controlling the proportional flow output at the flow control oil outlet on the proportional flow control valve, the rotating speed of the hydraulic motor unit can be controlled, so that the stepless speed regulating control can be realized; in use, a user can adjust the optimized sweeping speed based on the road pollution degree of different road segments, and the best sweeping effect can be achieved; the excessive oilcan be returned from the bypass oil leaking opening of the proportional flow control valve to a hydraulic oil tank, so that energy saving of the system can be realized; energy consumption loss is little, heating is small, and substantive features and notable progress are provided; a hydraulic cylinder unit is connected between an outlet end of a one-way valve and an oil-returning mouth of the hydraulic oil tank, which is convenient to drive the sweeping discs of the cleaning sweeper truck to rotate.

The invention relates to a three-function automatically switched matching power supply and belongs to the technical field of electronics. The three-functions automatically switched matching power supply comprises a DC rectification unit, an AC rectification unit, a switch lightning protection unit, an AC operating unit, an AC backup unit, a load unit, a storage battery, a charging unit, an isolation unit, a conversion control unit, and a silicon controlled rectifier (SCR) conversion unit. The OR-gate diodes of the two rectification units are connected to the switch lightning protection unit. The switch lightning protection unit is formed by a lightning protection relay and a lightning protection voltage-stabilizing tube connected in series. The lightning protection voltage-stabilizing tube generates protection during overvoltage. The AC rectification unit output supplies current to an AC power supply unit and the conversion control unit. The DC rectification unit output supplies current to the charging unit. When the load unit is connected and AC power is provided, the conversion control unit is started and the SCR conversion unit is switched off so as to achieve an AC power supply circuit. When no AC power is provided, the conversion control unit is cut off and the SCR conversion unit is activated so as to achieve a DC power supply circuit. A three-terminal integrated circuit supplies power in a normal state. The three-function automatically switched matching power supply has all advantages of a three-terminal integrated circuit.

The invention belongs to the technical field of electric apparatuses, more particularly discloses an AC overvoltage protection device. The AC overvoltage protection device consists of a power circuit, a voltage detection and comparison control circuit connected with the power circuit, and a micro control unit (MCU) which is connected with the power circuit and based on an external memory or a built-in memory and has a clock sensing function. An output terminal of the voltage detection and comparison control circuit is connected with the MCU which is connected with various loops of a protected electrical apparatus. The AC overvoltage protection device has the advantages of stable supply voltage and high voltage resistance, can ensure operating correctness and stability of the device, has wide high-voltage protection scope and can better perform timely protection in the event of abnormal voltage. In addition, as the AC overvoltage protection device has simple structure and small size, the device can be directly designed on a circuit board, mass production can be realized without modifying procedures, and the manufacturing cost is low.

The invention relates to a double-ground-wire precise matching power supply and belongs to the technical field of electronics. The double-ground-wire precise matching power supply comprises a rectification unit 1, a floating charge constant-voltage unit, a storage battery, a rectification unit 2, an overvoltage protection unit 1, a switching control unit, an AC power supply unit 1, an AC power supply unit 2, a load equivalent unit, an automatic switching unit, and an overvoltage protection unit 2. The positive pole of the storage battery and the output ends of the AC power supply units are connected with the power end of the load equivalent unit. The grounding end of the load equivalent unit is connected with the automatic switching unit. The automatic switching unit is controlled by the switching control unit. When AC power is provided, the switching control unit is activated and the automatic switching unit is disconnected so that the storage battery is not discharged. When no AC power is provided, the switching control unit is disconnected and the storage battery is discharged to supply power to a load. The double-ground-wire precise matching power supply is fast in switching speed so as not to have an influence on the load for ensuring the performance of the load. The double-ground-wire precise matching power supply forms multistage overvoltage protection, has wider adaptability than a traditional power supply, can be widely adapted to the needs of the load.

A method for controlling a variable speed drive supplying power to an electric motor, the variable speed drive comprising a plurality of at least Ni low-voltage power cells connected in series, comprising:

• • upon reception of a speed command, determining a number Mi of cells sufficient to supply power to the motor at a target voltage V that is determined based on the speed command; and
  • activating the Mi power cells from among the Ni power cells, and deactivating the Ni-Mi other power cells in order to supply power to the motor in accordance with the speed command.

The invention is related to a luminaire comprising a lighting module for emitting light, a driver for driving operation of the lighting module, a runtime overvoltage protection device for protecting the lighting module and the driver from exposure to overvoltage above a first overvoltage tripping limit, and a provisional overvoltage protection device that is connected in parallel to the runtime overvoltage protection device and has a second overvoltage tripping limit. The second tripping limit smaller than the first overvoltage tripping limit so that the provisional overvoltage protection device provides overvoltage protection to the runtime overvoltage protection device. Moreover, the provisional overvoltage protection device is deactivatable.