9 results about "Doubly fed electric machine" patented technology

The application discloses a full-order terminal sliding mode control method for a brushless doubly-fed motor independent power generation system, and belongs to the field of motor control. The application solves the problem that the traditional full-order terminal sliding mode control algorithm does not simultaneously consider the matching and non-matching uncertainty caused by motor parameter perturbation in the motor model, resulting in low system output voltage precision, poor system anti-interference ability and control effect. According to the brushless doubly-fed motor mathematical model, the application considers the matching and non-matching uncertainty caused by brushless doubly-fed motor parameter perturbation, determines the voltage loop state equation of the non-matching power winding outer ring voltage subsystem and the current loop state equation of the matching control winding inner ring current subsystem, and designs corresponding inner and outer loop full-order terminal sliding mode controllers for the subsystems to compensate the uncertainty, so that the tracking error of the power winding voltage amplitude converges to zero, and the tracking error of the control winding current amplitude converges to zero. The application is mainly suitable for independent power generation control when the brushless doubly-fed motor is connected to a balanced load.

The present application relates to the technical field of energy storage, in particular to a network-constructed double-fed flywheel energy storage unit control loop starting and grid-connection method and system, the method comprising: starting a grid-side converter, including pre-charging a DC capacitor, and starting the grid-side converter control loop in turn according to a preset timing sequence: first starting a phase-locked loop, then starting a current loop, and finally synchronously starting a DC voltage loop and a reactive power loop; three-phase short-circuiting a double-fed motor stator, starting the flywheel and accelerating to a set speed by using a machine-side converter phase-locked loop and a network-constructed current control loop; opening the double-fed motor stator, starting the machine-side network-constructed control loop according to the timing sequence, and connecting to an AC power grid. Through the method and system, the flywheel can be directly started under network-constructed control and connected to the power grid, which is suitable for operation under weak power grid conditions and is more conducive to stable operation of the system.

This invention discloses an online identification method and system for dual inductor parameters of a doubly-fed induction generator (DFIG) MRAS position observer, belonging to the field of sensorless control for doubly-fed variable-speed pumped storage. The method includes: a stator leakage inductance coefficient identification step and a mutual inductance coefficient identification step. The stator leakage inductance coefficient identification step includes: performing coordinate transformation on the position observed by the observer, the α' component and β' component of the rotor current to obtain the identified q-axis component of the rotor current; constructing a stator leakage inductance coefficient identification formula for identifying the stator leakage inductance coefficient to obtain the stator leakage inductance coefficient identified at the current moment; the mutual inductance coefficient identification step includes: using the stator leakage inductance coefficient identified at the current moment to perform online mutual inductance coefficient identification to obtain the mutual inductance coefficient identified at the current moment. This invention pertains to online identification of mutual inductance and stator leakage inductance coefficients under sensorless control conditions, which can improve the accuracy of the MRAS position observer and ensure the power control performance of the doubly-fed variable-speed pumped storage unit.

This invention discloses a grid-connected frequency control method for a doubly-fed induction generator (DFIG) based on a fractional-order adaptive virtual synchronous generator (VSSG), belonging to the field of wind power grid-connected control technology. The method first establishes a mathematical model for DFIG grid connection and monitors grid frequency and active power in real time. Second, it constructs a grid-side VSG control model, analyzes the influence of rotational inertia J and damping coefficient D on the system's dynamic response, and designs adaptive VSG control. Based on this, fractional-order control theory is introduced, and a fractional-order VSG control module is designed. The system's frequency regulation performance is optimized using a non-integer-order differential operator. Finally, the controller parameters are optimized to achieve rapid dynamic response and frequency stability. By combining fractional-order control and adaptive VSG strategies, this invention effectively suppresses power oscillations and frequency overshoot during grid frequency fluctuations, improving the frequency support capability and transient stability of the DFIG grid-connected system. It is suitable for frequency control applications in power systems with a high proportion of renewable energy integration.

The application discloses a kind of brushless doubly-fed motor natural synchronization operating condition operation characteristic analysis method, comprising: based on the frequency conversion of brushless doubly-fed motor winding, obtain the winding loop voltage equation of brushless doubly-fed motor natural synchronization operating condition;Based on the winding loop voltage equation of brushless doubly-fed motor natural synchronization operating condition, equivalent circuit is deduced and solved;On the basis of equivalent circuit solving result, the power angle of brushless doubly-fed motor is calculated, and then the active output characteristic, electromagnetic torque and excitation characteristic of brushless doubly-fed motor are obtained.The present application can clearly analyze the maximum output power and static performance of brushless doubly-fed motor under the excitation of brushless doubly-fed motor constant voltage source, effectively solve the problem that traditional brushless doubly-fed motor equivalent circuit cannot accurately analyze natural synchronization operating condition operation, and provide a theoretical analysis basis for brushless doubly-fed motor control winding DC excitation control mode.

This invention belongs to the field of wind turbine control technology, specifically a fault ride-through control method for a doubly-fed induction generator (DFIG) based on transient impedance and power angle compensation. The method includes: acquiring a first electrical quantity characterizing the rotor current; determining whether the first electrical quantity exceeds a preset safety threshold; when the safety threshold is exceeded, adaptively generating a transient virtual impedance based on the over-limit deviation; generating a compensation torque based on the virtual power dissipation corresponding to the transient virtual impedance; introducing the compensation torque into the swing equation of a virtual synchronous generator to compensate for the power balance offset generated during current limiting; and generating a drive signal for the rotor-side converter based on the output of the virtual synchronous generator, the transient virtual impedance, and the positive and negative sequence voltage and current components. This invention can suppress rotor overcurrent in the DFIG during fault ride-through and reduce the risk of power angle offset and instability in virtual synchronous control.

The application provides a method and system for operation analysis based on a double-fed motor model. The method comprises the following steps: obtaining first characteristic frequency value information of a reference double-fed motor and first acquisition time information corresponding to the first characteristic frequency value information; obtaining second characteristic frequency value information corresponding to a plurality of motor models to be evaluated; obtaining second acquisition time information corresponding to each second characteristic frequency value information; generating characteristic frequency mean value information based on the same second acquisition time information and the plurality of second characteristic frequency value information; and determining target correction time information based on the first characteristic frequency value information and the characteristic frequency mean value information. The application can accurately identify the key time node of the motor model that needs manual correction, realize the transition from fixed cycle operation and maintenance to state-driven on-demand intervention, effectively guarantee the accuracy of the simulation results, and significantly improve the long-term reliability of the model operation.

This invention discloses a doubly-fed induction generator (DFIG) hydroelectric power generation system and its control method. The DFIG hydroelectric power generation system includes a turbine, a DFIG, a dual PWM inverter, a transformer, a bypass switch, a chopper resistor, a chopper device, a selector switch, and a control unit. The output terminal of the DFIG rotor winding is connected to the power grid through the dual PWM inverter and a second transformer. The three-phase line between the output terminal of the DFIG rotor winding and the input terminal of the dual PWM inverter is connected to a common point through the bypass switch. The chopper resistor is arranged in parallel on the DC bus of the dual PWM inverter through the chopper device. The control terminals of the dual PWM inverter, the bypass switch, and the chopper device are respectively connected to the control unit. This invention aims to achieve long-term, continuous, and stable power generation with optimal efficiency from the DFIG hydroelectric generator, thereby increasing power output while meeting the requirements of ecological water resource protection.