Power Conversion Device Voltage Control for Battery Priority
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Solution Overview
Problem
Existing power conversion systems struggle to control the output power of distributed power supplies operating as AC current sources, leading to inefficient power management during self-sustained operations, particularly when storage batteries are involved, as they cannot prioritize power discharge from specific batteries based on their state of charge, resulting in potential battery depletion and system instability.
Innovation Solution
A power conversion device with a DC/DC conversion unit, inverter unit, and control systems that adjust AC voltage output based on the power generation amount and state of charge of solar and storage batteries, allowing preferential supply of solar-generated power and controlled discharge from batteries, ensuring optimal power distribution and minimizing battery discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If distributed power supplies operate as AC current sources in parallel self-sustained operation, then power supply capability is improved, but control over output power amount and priority discharge from specific storage batteries cannot be achieved
Solution Approach 1:
The patent changes the control parameter from current-based control to voltage-based control. By controlling the AC voltage amplitude of each distributed power supply, the system can precisely regulate output power amount. The voltage control unit adjusts the voltage amplitude according to priority levels, enabling both high power supply capability and fine-grained control over output power.
2Adaptability or versatility
If distributed power supplies operate as AC current sources, then parallel operation capability is improved, but ability to prioritize power discharge from specific storage batteries is lost
Solution Approach 1:
The patent applies local quality by assigning different voltage amplitudes to different distributed power supplies based on their priority levels. Each power supply operates with a locally optimized voltage amplitude that reflects its priority status, enabling the system to maintain parallel operation capability while achieving differentiated priority discharge control through local parameter adjustment.
3Device complexity
If AC voltage amplitude is not controlled, then system simplicity is maintained, but power management efficiency and battery utilization deteriorate
Solution Approach 1:
The patent introduces dynamic voltage amplitude adjustment based on real-time priority levels and power generation conditions. The voltage control unit dynamically modifies the AC voltage amplitude of each distributed power supply, enabling efficient power management and optimal battery utilization while maintaining relatively simple system architecture through centralized control logic.
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 solution enables efficient power management by prioritizing solar-generated power and minimizing storage battery discharge, preventing battery depletion and ensuring continuous operation even under high load conditions, thereby maximizing the utilization of generated power and maintaining system stability.
Implementation Method 1
a solar battery 1 for generating electric power by utilizing solar energy
Implementation Method 2
a storage battery 2 for storing electric power
Implementation Method 3
a first DC/DC conversion unit 13 for converting first DC voltage outputted from the first DC power supply 1, to second DC voltage
Implementation Method 4
an inverter unit 21 for converting DC voltage to AC voltage, or for converting AC voltage to DC voltage
Data Source
AI summary
In the case of performing self-sustained operation, when power conversion devices supply power to loads, all DC/AC conversion circuits of the power conversion devices are operated in a voltage control mode, and effective voltage (amplitude) of reference AC voltage as a control target for AC power outputted from each DC/AC conversion circuit under voltage control is adjusted in accordance with the power generation amount of a solar panel as a DC power supply, and the state of charge of a storage battery, thereby the amount of power supplied to the loads is controlled.