Inverter-Based Battery Power Transfer for Voltage Equalization
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Solution Overview
Problem
Existing electrical power converters lack the capability to efficiently transfer electrical power between a first storage battery and a second storage battery, particularly in scenarios requiring high-voltage charging and voltage equalization.
Innovation Solution
The proposed electrical power converter includes a high-potential electrical path, a low-potential electrical path, an inverter with upper and lower arm switches, a motor with armature windings, a battery-to-battery switch, a bypass switch, and a control device that determines power transfer requests and controls the operation modes of the switches to facilitate efficient power transfer between the batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a relay is used to change connection between first and second storage batteries to series-connection or parallel-connection for charging, then the system can be charged using external chargers with different voltages (400V or 800V), but the system cannot transfer electrical power between the first and second storage batteries
Solution Approach 1:
The inverter is designed to perform multiple functions: it can operate as a conventional inverter for motor control and simultaneously function as a power transfer device between the first and second storage batteries. By utilizing the existing inverter structure with upper and lower arm switches, the system achieves battery-to-battery power transfer without adding dedicated power conversion equipment, thus resolving the contradiction between versatility and device complexity.
Solution Approach 2:
The inverter acts as an intermediary device between the first and second storage batteries. Through controlled switching of the upper and lower arm switches, the inverter mediates the power flow between batteries with different voltages, enabling efficient power transfer while isolating the batteries from direct connection. This intermediary approach avoids the need for complex direct connection switching mechanisms.
2Adaptability or versatility
If direct connection between storage batteries is implemented for power transfer, then power transfer capability is achieved, but voltage differences between batteries cause current imbalance and potential damage
Solution Approach 1:
The inverter serves as a protective intermediary between the first and second storage batteries. By controlling the switching states of upper and lower arm switches, the inverter regulates the power flow and prevents direct uncontrolled connection between batteries with different voltages. This intermediary mechanism enables power transfer capability while simultaneously protecting the batteries from voltage imbalance and current overload, resolving the contradiction between versatility and reliability.
Solution Approach 2:
The system dynamically changes operational parameters (switching states of upper and lower arm switches) based on the voltage states of the first and second storage batteries. By adjusting these parameters in real-time, the inverter adapts to voltage differences between batteries, enabling safe power transfer while preventing damage from uncontrolled current flow, thus resolving the contradiction between power transfer capability and battery protection.
3Adaptability or versatility
If additional switches and control mechanisms are added to enable battery-to-battery power transfer, then power transfer functionality is achieved, but the device structure becomes more complex
Solution Approach 1:
The inverter structure is designed to be universally applicable for both conventional motor control and battery-to-battery power transfer. By configuring the upper and lower arm switches in different states, the same inverter hardware achieves multiple functions without requiring additional dedicated switches or complex control mechanisms, thus resolving the contradiction between versatility and device complexity.
Solution Approach 2:
The inverter employs dynamic switching of upper and lower arm switches to adapt its configuration based on operational requirements. For power transfer mode, specific switches are turned on/off to create appropriate current paths; for motor control mode, different switching patterns are used. This dynamic reconfiguration allows a single inverter structure to serve multiple purposes without permanent structural modifications, resolving the contradiction between adaptability and complexity.
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 enables efficient electrical power transfer between the first and second storage batteries, allowing for high-voltage charging and voltage equalization, thereby improving the overall efficiency and reliability of the power conversion system.
Implementation Method 1
an inverter which includes upper arm switches and lower arm switches, the upper arm switches being electrically connected with the high-potential electrical path, the lower arm switches being electrically connected to the low-potential electrical path
Implementation Method 2
a motor which includes armature windings electrically connected to joints of the upper arm switches and the lower arm switches through conductors
Data Source
AI summary
An electrical power converter includes an inverter, a motor with armature windings, a battery-to-battery switch in a battery-to-battery electrical path connecting with a negative terminal of a first storage battery and a positive terminal of a second storage battery, a bypass switch, a motor electrical path connecting the armature windings to the battery-to-battery electrical path, and a control device. When determining that a request is made to transfer electrical power between the first and second storage battery, the control device sets a first or second operation mode for the battery-to-battery switch and the bypass switch and performs a switching operation of the inverter to transfer electrical power between the first and second storage batteries. The battery-to-battery switch is turned on while the bypass switch is turned off in the first move. The battery-to-battery switch is turned off while the bypass switch is turned on in the second mode.