5results about How to "Surge suppression" patented technology

The application discloses a method, medium and system for determining the closing speed of a phase-selected vacuum switch for closing a capacitive load, comprising: repeatedly performing multiple closing experiments on the fast vacuum switch at different closing speeds and at different closing phases under a power frequency voltage; collecting the minimum pre-breakdown voltage and the power frequency voltage corresponding to the closing process of each closing speed; drawing the curve of the minimum pre-breakdown voltage corresponding to each closing speed of the fast vacuum switch changing with time and the curve of the power frequency voltage changing with time; if the closing process corresponding to at least one closing speed meets a first preset requirement, selecting the smallest closing speed as the lower limit of the closing speed of the fast vacuum switch; and the first preset requirement is that the slope of the curve of the minimum pre-breakdown voltage changing with time is greater than the slope of the curve of the power frequency voltage changing with time at the same time. The application determines the minimum closing speed, and reduces the pre-breakdown high-frequency inrush current in the process of closing the capacitive load by the vacuum switch.

This invention discloses an energy-saving ammonium chloride evaporation crystallization system and process. The system includes a feed preheating unit, a first-effect falling film evaporation unit, a second-effect falling film evaporation unit, and a forced circulation evaporation crystallization unit connected sequentially along the feed liquid flow direction. It also includes a falling film scrubbing tower, a forced circulation scrubbing tower, and a three-stage compressor. The forced circulation secondary steam, after scrubbing, enters the first-stage compressor. The second-effect secondary steam, after scrubbing, bypasses the first-stage compressor and merges at the outlet side of the first-stage compressor. It is then compressed in the second and third stages and reused for the first-effect falling film evaporation and forced circulation evaporation crystallization. This process, by setting the falling film evaporation to double-effect, only compresses the second-effect and forced circulation secondary steam; by using the first-stage compressor to separately increase the temperature rise of the forced circulation secondary steam, compensating for its high boiling point rise, it merges with the second-effect steam and is then compressed in the second and third stages for reuse. Since the boiling point rise in the falling film section is low, the second-effect steam only requires two stages of compression to meet the heat transfer temperature difference. This effectively reduces the amount of gas passing through and power consumption, and improves stability.

The application relates to the technical field of underwater power supply, and provides a surge protection circuit and an underwater medium-voltage conversion power supply, which comprise a protection subcircuit and a reset subcircuit arranged in parallel. The protection subcircuit is arranged between a power supply end and a subsequent circuit, and the protection subcircuit is connected in parallel with the subsequent circuit. The protection subcircuit comprises at least one protection device, which is used for turning on the protection subcircuit to short-circuit the subsequent circuit when the change rate of input voltage of the power supply end is greater than a preset threshold value and the input voltage is greater than a first breakdown voltage. The reset subcircuit is arranged between the protection subcircuit and the subsequent circuit, and is used for closing the circuit to reset the protection subcircuit after the protection subcircuit is turned on. Based on the scheme provided in the embodiment, the protection subcircuit is rapidly turned on when a transient high-voltage impact is detected, the surge current is discharged, the reset subcircuit automatically cuts off the protection path after the surge ends, the normal power supply of the system is restored, and the operation reliability and self-recovery ability of the medium-voltage conversion power supply in a complex marine environment are improved.

The invention discloses an air supply device and method for a cathode closed electric pile or a methanol fuel cell. The device comprises a high-speed brushless direct current motor, a centrifugal impeller directly driven by the high-speed brushless direct current motor, a volute for packaging the impeller and an electronic control unit. The impeller and the volute are pneumatically optimized, so that the device has high efficiency and a wide stable working area under the back pressure of 1-10kPa. The electronic control unit takes the load current of the electric pile as a main feed-forward signal, quickly sets the target rotating speed of the motor through a built-in mapping table, and realizes accurate tracking by adopting a rotating speed closed loop. The control unit is integrated with mechanisms such as self-learning compensation, anti-disturbance quick response, safety protection and anti-integral saturation. According to the invention, the harsh requirements of a miniaturized fuel cell system on high back pressure, fast response, small size and long service life of an air supply component are met.

The embodiment of the application discloses a control method and device of a fuel cell turbo-compressor. The method comprises the following steps: identifying a current working condition according to an operating parameter; in a slow load reduction working condition, slowly opening a bypass valve, slowly closing a variable nozzle ring, reducing a high-speed drive motor speed and a throttle opening degree, maintaining a compressor outlet flow rate not lower than a minimum safe flow rate, recovering turbine residual pressure energy and motor rotor kinetic energy; in a rapid load reduction working condition, quickly opening the bypass valve, quickly closing the variable nozzle ring, reducing the high-speed drive motor speed and the throttle opening degree, maintaining the compressor outlet flow rate not lower than the minimum safe flow rate, recovering the turbine residual pressure energy and the motor rotor kinetic energy; in an emergency shutdown working condition, fully closing the variable nozzle ring, fully opening the bypass valve, idling the high-speed drive motor, keeping the throttle at a purge opening degree and stopping the system after the purge is completed, so that on-line surge suppression, pressure overshoot control and energy recovery are coordinated, and the system safety and energy utilization rate are improved.