Power Conversion Device Virtual Power Generation Model Control
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Solution Overview
Problem
Conventional power conversion devices face challenges in accurately controlling AC power frequency, seamless switching between system interconnecting and self-sustaining operations, and effective utilization of limited storage battery power, particularly when connected to storage batteries.
Innovation Solution
The power conversion device incorporates a virtual power generation device model unit with a motor model, AVR model, and governor model to generate pulse width modulation signals for precise AC power frequency control, seamless operation switching, and efficient battery charging, utilizing a control signal generation unit that calculates current command values based on angular velocity differences and field equivalent values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional virtual power generation device model unit is used, then the system frequency and voltage can be stabilized, but the AC power frequency control accuracy deteriorates when connected to external generators
Solution Approach 1:
The control device is divided into separate functional units: a virtual power generation device model unit for frequency stabilization and a phase synchronization unit for accurate frequency control. This segmentation allows each unit to specialize in its function without interference, resolving the contradiction between stability and precision.
Solution Approach 2:
The phase synchronization unit acts as an intermediary between the power conversion circuit and the external power system. It calculates the phase difference between internal and external AC power and generates correction signals, enabling accurate frequency control while maintaining system stability through coordinated operation.
2Adaptability or versatility
If the power conversion device operates in system interconnecting mode, then power can be shared with external generators, but seamless switching to self-sustaining operation becomes difficult
Solution Approach 1:
The control device dynamically adapts its operation mode based on system conditions. The virtual power generation device model unit continuously adjusts its parameters to maintain stability whether in interconnecting or self-sustaining mode, enabling smooth transitions without manual intervention or system disruption.
Solution Approach 2:
The control device is designed with multi-functionality to handle both system interconnecting operation and self-sustaining operation using the same core control architecture. The virtual power generation device model unit provides universal frequency stabilization capabilities across different operation modes, eliminating the need for separate control systems and enabling seamless switching.
3Quantity of substance
If a storage battery is used as DC power supply, then power can be stored and reused, but the limited battery power is quickly depleted
Solution Approach 1:
The governor model unit implements feedback control by monitoring the operating state of the storage battery and adjusting the power output accordingly. When battery charge level decreases, the system automatically reduces power consumption and prioritizes essential functions, extending battery duration through continuous adaptive management.
Solution Approach 2:
The system performs preliminary assessment of battery charge levels and predicts future power needs. The governor model unit proactively adjusts operational parameters before complete power depletion occurs, optimizing power usage patterns and preparing for mode transitions to maintain operation throughout the available battery duration.
Data Source
AI summary
A power conversion device includes a power conversion circuit and a control device. The control device includes a virtual power generation device model unit and a control signal generation unit. The virtual power generation device model unit includes: a motor model unit; an AVR model unit; an angular velocity difference acquisition unit; and a power generator model unit. The control signal generation unit is configured to generate the pulse width modulation signal based on the current command value and an output current value from the power conversion circuit.