Power Converter Overmodulation for Grid Overvoltage Ride-Through
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power converters face challenges in handling overvoltage events on the power grid, leading to uncontrolled currents that can damage the converter and power sources, and disconnecting from the grid results in reduced stability and efficiency.
Innovation Solution
A power converter control method that switches to an overmodulation mode and increases reactive power consumption during overvoltage events, allowing it to remain connected to the grid and prevent uncontrolled currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power converter is tripped and disconnected from the AC grid during overvoltage events, then damage to the power converter and power source is prevented, but grid stability is reduced and power output is lost
Solution Approach 1:
The patent changes the operating parameters of the power converter by switching to overmodulation mode and adjusting reactive power consumption. This allows the converter to operate safely during overvoltage events by modifying its electrical characteristics rather than disconnecting, thus maintaining grid connection while preventing damage.
Solution Approach 2:
The patent dynamically adjusts the operating mode of the power converter based on grid voltage conditions. By transitioning between normal operation and overmodulation mode with increased reactive power consumption, the system adapts to overvoltage events in real-time, maintaining both protection and continuous operation.
2Reliability
If the power converter is overrated with low AC voltage compared to high DC voltage to prevent uncontrolled rectification, then damage during overvoltage events is prevented, but rated power is reduced and current ripple increases
Solution Approach 1:
Instead of permanently overrating the converter with reduced AC voltage, the patent dynamically changes operating parameters by switching to overmodulation mode during overvoltage events. This temporary parameter adjustment prevents uncontrolled rectification while maintaining optimal rated power and efficiency during normal operation.
3Reliability
If the AC voltage is lowered relative to DC voltage to prevent uncontrolled currents, then power source and diode damage is prevented, but power output is reduced and current ripple increases
Solution Approach 1:
The patent dynamically adjusts voltage relationships by increasing reactive power consumption during overvoltage events. This temporary dynamic adjustment prevents uncontrolled currents and protects components while maintaining optimal power output and efficiency during normal operating conditions.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A method of controlling a power converter during an overvoltage event is provided. The power converter (100) is arranged to convert electrical power received from a power source (150) into AC electrical power that is fed into a power grid (200). The power converter (100) comprises plural semiconductor switches that are operated using a pulse width modulation, PWM, technique. A parameter (M, va, vg) indicative of a voltage on a grid side of the power converter (100) is monitored. The power converter (100) is operated in a first operating mode (31) in which the power converter feeds electrical power into the power grid (200). Upon detecting an overvoltage condition based on the monitored parameter, the power converter (100) is operated in a second operating mode (32) different from the first operating mode (31), wherein the second operating mode (32) is a ride through mode in which the power converter (100) remains connected to the power grid (200).