Phase-angle offsettng converter to minimize damaging effects of sudden phase changes due to network disturbance
View Patent ↗A system for a wind energy installation. The wind energy installation feeds electrical power into a power supply system. A phase control device can include a power supply system fault detector, a phase angle detector, and a signal processing module. When a power supply system fault is detected, a phase error signal can be determined. A preset angle signal can be determined based on the phase error signal. The preset angle signal can be provided to a converter which can emit electrical power having a phase angle corresponding to the preset angle signal into the power supply system. Accordingly, an undesirable sudden surge in power output resulting from a phase change occurring at the end of the power supply system disturbance can be avoided.
1. A system for use with a generator for feeding electrical power into a network, the system comprising:
a network fault detector identifying a fault in a network;
a phase angle detector determining a phase signal when a fault in the network has been identified;
an angle error calculation unit interacting with the network fault detector and being configured to perform a comparison between the phase angle before and after onset of the fault in the network and to generate a phase error signal based on said comparison;
a signal processing module determining a preset angle signal which varies with the phase error signal; and
a converter comprising a control line receiving the preset angle signal, the converter emitting electrical power having a phase angle which is offset corresponding to the preset angle signal.
2. The system of claim 1 , wherein the signal processing module comprises a lead module determining a lead angle based on the phase error signal.
3. The system of claim 2 , wherein the lead module comprises a divider having a divisor of 2.
4. The system of claim 2 or 3 , further comprising a characteristic element limiting the lead angle to adjustable limit values.
5. The system of claim 4 , wherein the limit values are determined based on permissible power and wattless-component ranges stored in a memory.
6. The system of claim 1 , 2 , or 3 , wherein the phase angle detector comprises a pattern wave generator synchronized to a network frequency.
7. The system of claim 1 , further comprising:
a device identifying a network voltage return; and
a switching device providing a reference frequency signal to the converter upon identification of the network voltage return.
8. A system of claim 7 , wherein the reference frequency signal maps a network frequency.
9. A system of claim 7 or 8 , further comprising a phase locked loop (PLL) circuit forming the reference frequency signal.
10. A system of claim 9 , further comprising a freewheeling device decoupling the PLL circuit upon detection of the fault in the network.
11. A system of claim 7 or 8 , further comprising a protection unit determining a phase angle difference between the network and a network-side inverter of the converter both before and after identification of the network voltage return, and switching off the network-side inverter if the phase angle difference before identification of the network voltage return is less than the phase angle difference after identification of the network voltage return.
12. A wind energy system comprising:
a generator driven via a wind rotor;
a network fault detector identifying a fault in a network;
a phase angle detector determining a phase signal when a fault in the network has been identified;
an angle error calculation unit interacting with the network fault detector and being configured to perform a comparison between the phase angle before and after onset of the fault in the network and to generate a phase error signal based on said comparison;
a signal processing module determining a preset angle signal which varies with the phase error signal; and
a converter comprising a control line receiving the preset angle signal, the converter receiving electrical power from the generator and emitting electrical power having a phase angle which is offset corresponding to the preset angle signal.
13. A method for operating a converter for use with a generator, comprising:
identifying a fault in a network;
determining a phase angle when a fault in the network has been identified;
calculating a phase error signal by comparing the phase angle before and after onset of the fault in the network;
determining a preset angle signal which varies with the phase angle error;
receiving electrical power from the generator; and
emitting electrical power having a phase angle which is offset corresponding to the preset angle signal.
14. A method of claim 13 , wherein the generator is driven by a wind rotor of a wind energy installation and the network is connected to the wind energy installation.