Active Rectifier Controller for Generator DC Link Voltage Stability
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Solution Overview
Problem
Integrated drive generators face electrical overstress and design constraints due to varying DC link voltage, which affects response time and requires high-voltage electronics, leading to complex and expensive designs.
Innovation Solution
A controller system with an AC-to-DC converter and regulator controller that maintains a constant DC voltage, using a boost converter to convert 3-Phase PMG to a fixed high voltage for the exciter drive, enabling pulse width modulation control and improving load transient responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a diode bridge is used to rectify PMG output, then the structure is simple, but the DC link voltage varies significantly causing electrical overstress and requiring high-voltage electronics
Solution Approach 1:
The patent changes the operating parameters of the rectification system by introducing active switching devices (MOSFETs/IGBTs) instead of passive diodes, enabling controlled rectification that maintains DC link voltage within a stable range, thereby eliminating electrical overstress conditions
Solution Approach 2:
The patent transitions from a static passive diode bridge to a dynamic active rectifier with controllable switching elements, allowing real-time adjustment of rectification characteristics to maintain stable DC link voltage under varying operating conditions
2Reliability
If high-voltage electronics are used to handle DC link variation, then electrical overstress is prevented, but the design becomes more complex and expensive
Solution Approach 1:
The patent applies preliminary action by actively regulating the DC link voltage before it can vary into dangerous ranges, using the active rectifier to preemptively maintain voltage stability and prevent the need for high-voltage rated electronics
3Device complexity
If the exciter drive operates at lower voltages, then the system is simpler, but the exciter requires higher exciter current and has less ability to extract energy
Solution Approach 1:
The patent introduces an intermediate active rectification stage that acts as a mediator between the PMG and exciter drive, enabling optimized voltage and current transformation that allows the exciter drive to operate at optimal voltage levels with reduced current requirements
4Adaptability or versatility
If a wide input voltage range is handled by the exciter drive, then adaptability is improved, but the design becomes more expensive and complex
Solution Approach 1:
The patent segments the voltage conversion function into two distinct stages: an active rectifier stage that handles the wide input voltage range from the PMG, and an exciter drive stage that operates at a narrower, optimized voltage range, thereby reducing the complexity requirements of each individual stage
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
This solution stabilizes the DC link voltage, reduces exciter currents, simplifies high-voltage power supply conversion, and enhances response times to speed and load transients, preventing transient overvoltages and enabling more efficient generator control.
Implementation Method 1
The AC-to-DC converter rectifies an AC voltage received from the PMG into a DC link of the controller
Implementation Method 2
The boost converter and the boost converter controller of the controller can convert 3-Phase PMG to a fixed high voltage for use in driving the exciter
Data Source
AI summary
A system including a generator and a controller. The generator includes a permanent magnet generator (PMG), and an exciter. The controller manages operations of the generator. The controller includes an alternating current to direct current (AC-to-DC) converter that generates a direct current (DC) voltage, an exciter drive that provides a DC current to the exciter of the generator using the DC voltage created by the AC-to-DC converter in accordance with the control signal, and a regulator controller that drives the active AC-to-DC converter.