3results about How to "Eliminate Control Errors" patented technology

The present application relates to the technical field of power electronics, and especially relates to a three-level inverter neutral point potential balance control method and device, comprising injecting a first-stage zero sequence voltage into a three-phase modulation wave to obtain an intermediate modulation wave, outputting a second-stage zero sequence voltage adjustment amount to obtain an upper limit value and a lower limit value of the second-stage zero sequence voltage; obtaining a three-phase modulation signal; and separating the three-phase modulation signal into a positive bridge arm control signal and a negative bridge arm control signal. The three-level inverter neutral point potential balance control method, by means of two-stage zero sequence voltage injection design, independently realizes SVPWM modulation and neutral point potential balance control functions, and avoids the functional interference problem caused by single zero sequence voltage injection.

The application provides a rotor floating control method, device, storage medium and magnetic suspension bearing system. The method comprises the following steps: controlling rotor floating of the magnetic suspension bearing based on a determined center floating reference position; if the rotor floating fails, controlling rotor floating of the magnetic suspension bearing according to a first set floating direction based on the center floating reference position; wherein the first set floating direction is a set direction offset relative to the center floating reference position when the rotor floating. The scheme provided by the application can solve the problem that the current loop and displacement loop errors affect bearing control due to product structure, process and magnetic steel demagnetization.

This invention provides a system and method for controlling the surface quality of bearing steel produced from small-section cast billets, belonging to the field of iron and steel smelting technology. It includes spray nozzles, an infrared temperature measuring device, and a control module. The control module is used to predict the billet shell thickness distribution and surface thermal stress distribution in real time based on the real-time surface temperature of the corner and center regions of the billet, combined with the real-time casting speed and the real-time superheat of the molten steel, using a solidification thermal stress coupling model. Based on the billet shell thickness distribution and the surface thermal stress distribution, and again combined with the real-time casting speed and the real-time superheat of the molten steel, it predicts in real time the target cooling water deflection angle and target cooling water flow rate of the corresponding spray nozzles in the corner and center regions of the billet. The system controls the spray nozzles to adjust the opening of the flow regulating valves and the mechanical deflection angle in real time according to the predicted target cooling water deflection angle and target cooling water flow rate, thereby spraying cooling water onto the billet. This invention achieves precise control of the cooling intensity and cooling range of the cast billet.