62 results about "Grid friendly" patented technology

Electric vehicle (EV) charging apparatus and methods are described which allow the sharing of charge current between multiple vehicles connected to a single source of charging energy. In addition, this charge sharing can be performed in a grid-friendly manner by lowering current supplied to EVs when necessary in order to satisfy the needs of the grid, or building operator. The apparatus and methods can be integrated into charging stations or can be implemented with a middle-man approach in which a multiple EV charging box, which includes an EV emulator and multiple pilot signal generation circuits, is coupled to a single EV charge station.

The invention discloses a fractional frequency control method and system of a variable-speed wind power turbine. The method comprises the steps that a voltage signal and an electric current signal ofa power generator of the variable-speed wind power turbine are collected, and the electromagnetic torque output by the power generator is worked out; rotation speed information of the variable-speed wind power turbine is collected; according to the electromagnetic torque and the rotation speed information, based on inertia data of the variable-speed wind power turbine, the pneumatic torque estimator is worked out; the difference value between the pneumatic torque estimator and the theoretical optimal controlling torque is calculated, the torque controlling torque is built through a low pass filter according to the difference value, and finally, the torque controlling set value is obtained. The system comprises a voltage sensor, an electric current sensor, a rotation speed sensor, an electromagnetic torque calculating system, a pneumatic torque estimator calculating system, the low pass filter, a torque additional value building system and a torque controlling set value calculating system. According to the fractional frequency control method and system, the power grid friendly target that the smooth output power fluctuates on the power grid sensitive power section is considered, andmeanwhile, electric energy production is improved.

The present invention provides a wind farm power coordinated control method and system, characterized in that the method includes: determining the reactive power control working mode of the wind farm according to the grid dispatching command; calculating the reactive power loss of the wind farm; Calculate the total reactive power demand of the wind farm according to the working mode and reactive power loss of the wind farm; allocate the total reactive power demand of the wind farm according to the pre-set allocation principle of the total reactive power demand of the wind farm, and judge whether the total reactive power demand of the wind farm is If the reactive power output limit of the wind turbine is exceeded, the total reactive power demand of the wind farm will be borne by the wind turbine. If it exceeds, the wind turbine will firstly bear it, and the excess part will be borne by the reactive power compensation device. The technical method provided by the invention improves the "grid friendliness" of the wind farm, improves the safe and stable operation level of the grid in areas where large-scale wind power is centrally connected, and promotes the improvement of the wind power consumption capacity of the grid.

The invention discloses a method and a system for generating a switching resistance signal for identifying household transformer relationships. The switching resistance signal generation method of the present invention includes: Step 1, analyzing the characteristics of the current signal generated by resistance switching in the low-voltage distribution network; Step 2, determining the sampling frequency and the switching frequency point according to the power consumption of the low-voltage station area ; Step 3, generation of resistance switching signal and determination of duty cycle; Step 4, encoding of resistance switching signal; Step 5, noise processing and signal enhancement by way of load removal; Step 6, detection of transformer secondary side current , conduct frequency domain analysis to determine the relationship between households and households. The current signal generated by the invention can not only effectively filter the noise of the power grid, but also enhance the strength of its own characteristic signal through load removal processing, and has small switching current and stable signal, and has the advantages of simple operation, grid friendliness, and good recognition effect.

The invention discloses a power grid friendly transformation method suitable for a constant-speed wind turbine generator set. According to a constant-speed wind turbine generator set canonical topology structure composed of a wind turbine, a gearbox, an induction generator and a compensating capacitor, a set of power grid friendly transformation device composed of a doubly-fed motor, a permanent magnet motor and an alternating-direct-alternating current converter is newly added on the basis of the equipment. The power grid friendly transformation device is reasonably controlled, the power grid friendly degree of the constant-speed wind turbine generator set can be improved, and the functions of smoothing output power, achieving low voltage ride through and enhancing the reactive supporting capacity in the low voltage ride through period are specially achieved. The method is suitable for independently carrying out power grid friendly transformation on the single constant-speed wind turbine generator set and also suitable for carrying out power grid friendly transformation on a plurality of constant-speed wind turbine generator sets with approximate wind conditions at the same time, and the requirements of a power grid for smoothing the output power of the wind turbine generator set and having the low voltage ride through capacity and the reactive supporting capacity are met.