HVDC Bus Overvoltage Control via Backup Power Supply
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Solution Overview
Problem
In electrical power systems, particularly those with DC power buses, overvoltages can occur when the system controller becomes inoperable, leading to potential damage to components due to the inability to regulate voltage effectively.
Innovation Solution
A backup power supply system that monitors the operational status of key components and, when an overvoltage threshold is exceeded and a component becomes inoperable, communicates a signal to short the terminals of the electric machine, thereby reducing the bus voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the system controller is used to regulate voltage on the HVDC bus, then voltage regulation is achieved during normal operation, but the system becomes vulnerable to overvoltage damage when the controller loses power
Solution Approach 1:
The backup power supply is pre-configured and automatically activates when the system controller fails, performing the voltage regulation function in advance before overvoltage damage can occur. The backup supply monitors the HVDC bus voltage and triggers protective shorting action when voltage exceeds the threshold, preventing damage before it happens.
Solution Approach 2:
The backup power supply acts as a protective cushion against overvoltage conditions by providing an automatic fallback mechanism. When the primary controller fails, the backup supply immediately engages to prevent voltage from rising to damaging levels, cushioning the system against the harmful effects of controller failure.
2Object-affected harmful factors
If the backup power supply shorts the electric machine terminals to reduce bus voltage, then overvoltage protection is achieved, but additional hardware complexity is introduced
Solution Approach 1:
The backup power supply serves as an intermediary protective device between the HVDC bus and the electric machine terminals. It monitors voltage conditions and intermediates by activating the shorting function only when necessary, providing protection without being constantly engaged, thus balancing protection needs with system simplicity.
Solution Approach 2:
The backup power supply is designed to autonomously detect overvoltage conditions and activate the shorting protection without requiring external control signals. This self-service capability reduces the need for additional control circuitry and simplifies the overall system architecture while maintaining effective overvoltage protection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents overvoltages on the DC power bus by ensuring voltage regulation even when the system controller is inoperable, thereby protecting system components from damage.
Implementation Method 1
detecting an operating voltage on a high voltage direct current bus
Implementation Method 2
a converter operable to convert alternating current (AC) power received from the electric machine into direct current (DC) power
Implementation Method 3
shorting together a plurality of terminals of the electric machine
Data Source
AI summary
A system and method for preventing over voltages in a power system coupled to an electric machine are disclosed. Briefly described, one embodiment is a method comprising detecting an operating voltage on a high voltage direct current (HVDC) bus, determining if at least one component of the power system is operational, communicating a signal to a power converter of the power system when the detected operating voltage is greater than a threshold voltage and when the component is not operational, and shorting together a plurality of terminals of the electric machine.