Active Power Converter Control for AC-DC Voltage Matching
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Solution Overview
Problem
Existing electrical systems face challenges in providing a dynamic and robust interface between live AC and DC electrical networks, particularly in managing voltage parameters and energy transfer efficiently.
Innovation Solution
An electrical system comprising an active power converter and a passive filter, with a monitoring arrangement and controller that adjusts the active power converter's operation based on monitored AC voltage parameters and a mathematical model of the passive filter's electrical characteristics to ensure efficient energy transfer and voltage matching between AC and DC networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an active power converter is used to interface AC and DC networks, then energy transfer capability is improved, but voltage parameter control complexity increases
Solution Approach 1:
The system performs preliminary monitoring of AC voltage parameters (magnitude, frequency, phase) on the first AC connecting bus before controlling the active power converter. This advance detection allows the controller to pre-calculate appropriate control actions based on the mathematical model of the passive filter, reducing the complexity of real-time control decisions while maintaining effective energy transfer capability.
Solution Approach 2:
The monitoring arrangement continuously measures AC voltage parameters and feeds this information back to the controller. The controller uses this feedback along with the mathematical model of the passive filter to dynamically adjust the active power converter's operation, enabling precise voltage parameter control without requiring overly complex control algorithms.
2Stability of the object's composition
If a passive filter is included in the electrical system, then voltage stability is improved, but system complexity increases
Solution Approach 1:
The passive filter is designed to perform multiple functions simultaneously: it filters voltage harmonics to improve voltage stability, and its electrical characteristics are incorporated into the mathematical model that guides active power converter control. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in overall system complexity while maintaining voltage stability.
Solution Approach 2:
The passive filter acts as an intermediary element between the active power converter and the AC network. By positioning the monitoring arrangement on the first AC connecting bus (between the converter and filter), the system can measure voltage parameters that already account for the filter's influence, simplifying the control calculations needed to achieve stable voltage output on the second AC connecting bus.
3Measurement precision
If AC voltage parameters are monitored on the first AC connecting bus, then control accuracy is improved, but measurement complexity increases
Solution Approach 1:
The monitoring arrangement measures AC voltage parameters (magnitude, frequency, phase) on the first AC connecting bus before the voltage reaches the passive filter. This preliminary measurement allows the controller to calculate the expected voltage parameters on the second AC connecting bus using the mathematical model of the passive filter, improving control accuracy without requiring direct measurement on the output side where measurements would be more complex due to filter effects.
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
The system effectively manages energy transfer between AC and DC networks by controlling the active power converter to match voltage parameters, preventing excess voltage conditions and ensuring a stable, sinusoidal AC voltage profile, thus enhancing the robustness and efficiency of the interface.
Implementation Method 1
controlling the active power converter to convert a DC voltage received from the DC network into an AC voltage for supply to the AC network via the passive filter
Implementation Method 2
controlling the active power converter to match: a fundamental frequency and a phase of the AC voltage on the second AC connecting bus; with the fundamental frequency and the phase, respectively, of the operating AC voltage of the AC network
Data Source
AI summary
An electrical system and method of operating the same is provided. The electrical system includes a passive filter, an active power converter, a first AC connecting bus extending between the active power converter and the passive filter, a second AC connecting bus extending between the passive filter and an AC network, a DC connecting bus extending between the active power converter and a DC network, and a monitoring arrangement. The method includes operating in a first mode and subsequently operating in a second mode. The first mode includes determining a plurality of parameters of an operating AC voltage of the AC network based on a monitored AC voltage on the first AC connecting bus. The second mode includes controlling the active power converter to convert a DC voltage received from the DC network into an AC voltage for supply to the AC network via the passive filter.