3results about How to "Slow change" patented technology

The embodiment of the invention discloses a grid-connected control method and device for a network-forming converter and a storage medium. The grid-connected control method for the grid-forming converter comprises the following steps: if a grid-connected switch signal of a grid-connected switch is a closed signal, acquiring the current active power of the grid-forming converter; obtaining an electrical parameter adjustment instruction value according to the current active power and a preset active-frequency loop control model; wherein the active-frequency loop control model is determined according to an off-grid internal potential rotor angle parameter of the network construction type converter, a voltage phase angle of a power grid and a rotor angle motion model of the network construction type converter; and the electrical parameter adjustment instruction value is sent to the network construction type converter to execute electrical parameter control so as to reduce electrical parameter overshoot output by the network construction type converter. According to the scheme, the change of the electrical parameters including the active power, the reactive power and the frequency output by the network construction type converter can be more relaxed, and the energy impact brought to the power grid when the network construction type converter is connected to the grid is relieved.

This application provides an arc-extinguishing system and a circuit breaker, belonging to the field of electrical equipment technology. The arc-extinguishing system provided in this application includes a stationary contact, an arc-extinguishing chamber, and a stationary cover. The stationary contact includes a fixed part and a contact part connected to each other. The fixed part is connected to the base of the circuit breaker, and the contact part has a guide groove that extends through the contact part. The arc-extinguishing chamber is disposed on the contact part. The stationary cover is disposed on the portion of the contact part that does not contact the arc-extinguishing chamber. A hook and a limiting block are provided on the side of the stationary cover facing the contact part. The hook passes through the guide groove and hooks to the side of the contact part facing away from the stationary cover. The limiting block is located within the guide groove and contacts the groove wall. The stationary cover mentioned in this application can limit the position of the stationary cover in the thickness, length, and width directions of the stationary contact, reducing the probability of changes in the relative position between the stationary cover and the stationary contact. This improves the shielding efficiency of the stationary cover on the contact part, thereby increasing the reliability of the arc-extinguishing system.

This invention discloses a crystalline polyimide / polyimide composite material, its preparation method, and its applications. The method involves first uniformly mixing phenylhexacarboxylic acid trihydride with a diamine monomer, followed by a solid-phase reaction under argon atmosphere protection. After the reaction, the product is immersed in a polar solvent to obtain crystalline polyimide. Then, the crystalline polyimide is added to an organic solution of polyamic acid, subjected to ultrasonic treatment in an ice-water bath, and subsequently thermosetting to obtain the crystalline polyimide / polyimide composite material. The crystalline polyimide in this composite material has a layered two-dimensional COF structure, giving it relatively high thermal conductivity, heat resistance, and high-temperature mechanical properties. Introducing the crystalline polyimide into the polyamic acid solution utilizes the special interfacial compatibility between the amino groups in the crystalline polyimide and the anhydrides in the polyamic acid to react, solving the problem of difficult processing and effectively expanding its application range.