An excitation current-limited power generator includes a digital interface configured to be coupled to an engine control unit (ECU), a regulator coupled configured to be coupled to an excitation current input of an alternator, the excitation current controlling current generated by the alternator, a frequency sensor configured to measuring rotation speed of the alternator, and memory storing a communicated limit received by the digital interface and a first permanent limit, the regulator configured to limit the excitation current to the lesser of the first permanent limit and the communicated limit.

An excitation current-limited power generator includes a digital interface configured to be coupled to an engine control unit (ECU), a regulator coupled configured to be coupled to an excitation current input of an alternator, the excitation current controlling current generated by the alternator, a frequency sensor configured to measuring rotation speed of the alternator, and memory storing a communicated limit received by the digital interface and a first permanent limit, the regulator configured to limit the excitation current to the lesser of the first permanent limit and the communicated limit.

Overvoltage protection device for a variable-speed and constant-frequency electrical energy generation system includes at least one DC current generator connected, via a DC current bus to the input terminals of at least one inverter and to at least one regulation module for regulating the output voltage of the at least one inverter. The device includes a circuit including at least one switch in series with a resistor, the circuit being connected between the input terminals of the at least one inverter, at least one measurement sensor for measuring the DC voltage across the input terminals of the at least one inverter, a control circuit connected to the at least one measurement sensor and able to receive a voltage measured by the at least one measurement sensor, compare the measured voltage against a threshold and command the closure of the at least one switch if the measured voltage is greater than the threshold, and command opening thereof if not.

The application involves a stability evaluation method and system of direct-drive wind turbine generator, which belongs to the technical field of wind power generation. It solves the problems of poor stability of direct-drive wind turbine generator, low safety performance, failure to realize mutual cooperation between online stability evaluation and parameter adjustment in the existing technology. Firstly, the variation of direct-drive wind turbine generator terminal voltage, current, power and PLL angle of direct-drive wind turbine generator is measured, the terminal energy and the energy negative gradient of direct-drive wind turbine generator is calculated. Then, the system stability is assessed according to the value of energy negative gradient, the influence of the critical parameters on system stability is analyzed and the preliminary adjustment strategy is proposed. It realizes the mutual cooperation between stability level evaluation and parameter adjustment, and improves the working efficiency of the system.

An electric power conversion circuit includes: first and second input terminals; first and second output terminals; first and third switches connected to the first output terminal; second and fourth switches connected to the second output terminal; first through fourth diodes that are bridge-connected between the first and second switches; fifth through eighth diodes that are bridge-connected between the third and fourth switches; a first bootstrap circuit that is connected to control terminals of the second and fourth switches; and a second bootstrap circuit that is connected to control terminals of the first and third switches.

The present application provides a method and a system for controlling continuous high voltage ride-through and low voltage ride-through of a permanent magnet direct-driven wind turbine. The method includes: determining a transient time period during which the wind turbine is transitioned from a high voltage ride-through state to a low voltage ride-through state; controlling the wind turbine to provide, during the transient time period, a gradually increasing active current to the point of common coupling; and controlling the wind turbine to provide, during the transient time period, a reactive current to the point of common coupling according to an operation state of the wind turbine before the high voltage ride-through state.

An apparatus for controlling a turbogenerator system when a power electronics circuit of the turbogenerator system is unable to provide a sufficient load on the turbogenerator to prevent the turbogenerator from accelerating uncontrollably is described. The apparatus includes a monitor including a first sensing device operable to detect a condition of the turbogenerator, and a brake controller responsive to a turbogenerator detection output from the first sensing device to issue a first brake control signal for operating a brake circuit to prevent the turbogenerator from accelerating uncontrollably and a second brake control signal for operating the brake circuit to permit resumption of normal operation of the turbogenerator.

An apparatus for controlling a turbogenerator system when a power electronics circuit of the turbogenerator system is unable to provide a sufficient load on the turbogenerator to prevent the turbogenerator from accelerating uncontrollably is described. The apparatus includes a monitor including a first sensing device operable to detect a condition of the turbogenerator, and a brake controller responsive to a turbogenerator detection output from the first sensing device to issue a first brake control signal for operating a brake circuit to prevent the turbogenerator from accelerating uncontrollably and a second brake control signal for operating the brake circuit to permit resumption of normal operation of the turbogenerator.

A method and controller for controlling a Wound Field Synchronous Machine (WFSM) of an electric power generation system (EPGS) having a field winding and a stator armature winding is provided. The controller includes an adjustable component coupled to the generator and a power factor controller for adjusting the adjustable component to lower the power factor of the WFSM as a function of power output to a load of the EPGS to stabilize a current in the field winding.

The invention relates to a method for limiting structural loads in a wind turbine in situations where the power produced by the wind turbine is increased or decreased. The limitation of structural loads is achieved by restricting the power ramp rate, i.e. the rate of change of increases or decreases in produced power. The restriction is only invoked if a maximum change of the produced power or the corresponding internal power reference within a time window exceeds a given threshold.