32results about How to "Stable voltage and frequency" patented technology

The invention discloses a frequency stabilization control system of a permanent magnet wind-driven generator capable of adapting to changing torque. The control system comprises a control box and an industrial personal computer, wherein the control box is used for detecting a switch array state, detecting electrical parameters of the generator and controlling the connection and cut-off of a stator winding; and the industrial personal computer is used for controlling the control box to operate. Each stator winding of the generator is connected with a single switch, and the control system can control the generator to meet the requirements of multi-level loads. At the same time, the control system adopts an ADRC, and can accurately control the opening and closing of each switch to further control the number of the windings connected with stators so as to control the rotating speed of the rotors, adjust the output voltage frequency of the generator and maintain the output voltage frequency of the generator in a stable value.

The invention discloses a low pass filtering inversion system based on a capacitance feedback three-point oscillation circuit; the low pass filtering inversion system comprises a transformer T1, an inversion circuit, a logic control circuit connected with the inversion circuit, a low pass filtering circuit connected with a primary side of the transformer T1, and a phase shift processing circuit arranged between the logic control circuit and the low pass filtering circuit; the features are that the capacitance feedback three-point oscillation circuit is also connected in series between the phase shift processing circuit and the low pass filtering circuit; the capacitance feedback three-point oscillation circuit enables the inversion system to output more stable voltage frequency, thus protecting electric appliances, and the electric appliances can more smoothly work.

The invention relates to a black-start method and apparatus of a power grid. The black-start method of a power grid includes the steps: utilizing a cell energy storage power station in a fault area to determine a black-start power supply in the fault area; and controlling the control mode of the black-start power supply, and starting a set which is started preferentially. The technical scheme provided by the black-start method and apparatus of a power grid utilizes the cell energy storage system to make a black-start scheme, and overcomes the defect that self excitation and long power transmission time easily occur in a traditional black-start scheme so as to conform to the development trend of high capacity and large scale of energy storage of cell.

The invention relates to a method and a system for increasing micro-grid operation reliability, which belong to the technical field of micro-grid power supply. The technical solution is as follows: after being connected in series with a photovoltaic inverter (2), a photovoltaic array (1) is connected with a micro-grid alternating-current bus (9), and after being connected in series with a wind turbine converter (4), a wind turbine generator (3) is connected with the micro-grid alternating-current bus (9); after being connected in series with a first energy storage converter (6), a storage battery pack (5) is connected with the micro-grid alternating-current bus (9), and after being connected in series with a second energy storage converter (8), a flywheel energy storage system (7) is connected with the micro-grid alternating-current bus (9); the micro-grid alternating-current bus (9) is connected with a micro-grid load (11). The invention has the following beneficial effects: the method and the system not only can carry out good smooth control to maintain the stability of micro-grid voltage frequency when the randomly fluctuating power of the output side of a distributed power supply fluctuates, but also can provide instantaneous power support in the process that a micro-grid is switched from grid connection to grid disconnection, thus realizing the smooth transition of the micro-grid from grid connection to grid disconnection and uninterrupted power supply for the micro-grid load.

The invention discloses a single-phase converter control method and apparatus. An active current calibration parameter K<d> and a reactive current calibration parameter K<q> are obtained according toan angular speed of a power grid side voltage of the current control period; by combination with K<d> and K<q>, an active current and a reactive current are calibrated; by combination with a power grid side active current reference value and a power grid side reactive current reference value, active current deviation delta i<d> and reactive current deviation delta i<q> can be obtained; an output voltage u<ab>(k) is obtained according to the delta i<d> and delta i<q>, and the u<ab>(k) is subjected to pulse width modulation to obtain driving pulse of each switching tube in the single-phase converter; and the power grid side parameters can be adjusted by controlling the on-off of the switching tubes. According to the single-phase converter control method, the active current and the reactive current can be calibrated through the angular speed of the power grid side voltage; and equivalently, the active power and the reactive power are adjusted through the power grid side voltage frequency,so that the allocation of the active power and reactive power can satisfy requirements of an electric power system in a condition that the voltage frequency is changed, thereby improving active and reactive power adjustment accuracy and stability in the electric power system.

The invention discloses a renewable energy source cooling, heating and power microgrid system and a control method. The renewable energy source cooling, heating and power microgrid system comprises a power module and a cooling / heating module. According to the power module, a solar power generation system is sequentially connected with a DC / DC converter and a DC / AC converter in series and then connected with an AC bus, a wind power generation system is sequentially connected with an AC / DC converter and a DC / AC converter and then connected with the AC bus, a gas internal combustion generation system is directly connected with the AC bus, a storage battery pack is connected with the AC bus through a bi-directional DC / AC converter, variable power electricity storage hot water tanks are connected with the AC bus, and the AC bus is connected with a power distribution network through a PCC. The renewable energy source cooling, heating and power microgrid system and the control method have the advantages that clean renewable energy sources such as methane, wind energy and solar energy are adopted as energy sources of a cooling, heating and power microgrid, no pollution is caused to the environment, operation cost is very low, and the application range is wide; by the adoption of a multi-microsource energy supply mode, the problem of capacity allocation redundancy of a single energy supply system can be solved.

An optimal control method for multi-objective operation of a microgrid based on undisturbed switching. Step 1: For a switching system with multi-mode operation, each operating mode has its own controller; Step 2: Find an allowable control α * (t), based on the optimal control theory, the performance index function (3) is taken as a minimum value; Step 3: The control target of the island operation mode is to suppress the circulation and share the power equally; Step 4: Consider the microgrid grid-connected operation mode The operation target under the state, design the corresponding modal controller, and the non-disturbance switching compensation controller when switching from the island operation mode to the grid-connected operation mode; the non-disturbance switching compensation controller designed by the present invention can ensure the system stability and smooth continuous transient performance.

The invention discloses an error calibration method for a vehicle-mounted easy-to-maintain voltage transformer, which belongs to the technical field of transformer testing. The vehicle-mounted easy-maintenance voltage transformer error checking system of the present invention includes a vehicle-mounted platform, on which a standard voltage transformer, a test booster and a test box are arranged, and the standard voltage transformer is an inflatable epoxy barrel type Standard voltage transformer, the test booster is an inflatable epoxy barrel test booster, the test box is fixed with a voltage regulation control power supply, and the test box is also equipped with a transformer calibrator and a voltage load box , a remote controller and connecting wires, the multi-combination compensating reactor is set in the voltage regulation control power supply. The error calibration system of the present invention can be used for on-site calibration of 500kV-220kV voltage transformers. The height of the vehicle-mounted system is only 2.2m in the transportation state. The system is convenient for mobile transportation and traceability maintenance. The data is stable and reliable.