Electric Vehicle Power Conversion Device Parallel Architecture
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Solution Overview
Problem
The existing configuration of power converting apparatuses for electric motor vehicles, where a DC/DC converter unit is interposed between the inverter unit and the power storage element, results in power loss and reduced system efficiency due to the need for frequent power regeneration and supply between these components.
Innovation Solution
A power converting apparatus that connects the inverter unit and the power storage element in parallel, with a converter unit controlling power flow directly from the overhead wire, eliminating the need for intermediate power converting circuits between the converter unit and the power storage element or inverter unit, allowing optimal power management based on vehicle conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a DC/DC converter unit is interposed between the inverter unit and the power storage element, then power flow control is enabled, but power loss occurs and system efficiency deteriorates
Solution Approach 1:
The patent extracts the DC/DC converter unit from the power flow path between the inverter unit and power storage element, eliminating it entirely. The inverter unit directly connects to the power storage element, removing the source of power loss while preserving bidirectional power flow control capabilities through the inverter's inherent control functions.
Solution Approach 2:
The inverter unit is designed to perform multiple functions: it serves as both the motor controller and the power management interface with the power storage element. This multi-functionality eliminates the need for a separate DC/DC converter, reducing system complexity and energy loss while maintaining full power flow control capability.
2Ease of operation
If a DC/DC converter unit is interposed between the inverter unit and the power storage element, then charging and discharging control is enabled, but system efficiency is reduced
Solution Approach 1:
The DC/DC converter unit is removed from the system architecture. The inverter unit directly manages charging and discharging of the power storage element through pulse width modulation (PWM) control, eliminating the efficiency penalty associated with dual conversion stages while maintaining precise charge/discharge control capability.
Solution Approach 2:
The functions of the inverter unit and DC/DC converter unit are merged into a single inverter unit that directly interfaces with the power storage element. This consolidation eliminates energy losses at the converter interface while integrating power flow control and charge/discharge management into one unified control system.
3Adaptability or versatility
If the converter unit optimally controls power flow among overhead wire, inverter unit, and power storage element, then system adaptability is improved, but control complexity increases
Solution Approach 1:
The inverter unit is designed as a universal interface that handles all power flow scenarios: drawing power from the overhead wire, regenerating power to the overhead wire, charging the power storage element, and discharging the power storage element. This multi-functional design provides system adaptability while using a single control device rather than multiple specialized converters.
Solution Approach 2:
The control system uses feedback from the inverter unit to dynamically adjust power flow based on vehicle operating conditions, power storage element state of charge, and overhead wire voltage levels. This feedback mechanism enables optimal power management adaptability through a unified control approach rather than complex multi-device coordination.
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 configuration enhances system efficiency by directly controlling power flow among the overhead wire, inverter unit, and power storage unit, reducing power loss and improving the management of power regeneration and supply, thus optimizing energy usage in electric motor vehicles.
Implementation Method 1
an inverter unit (30) that drives an electric motor (40)
Implementation Method 2
when the vehicle is braked, a so-called regenerative brake for regeneratively operating the electric motor to obtain braking force
Implementation Method 3
a power storage element such as a secondary battery or an electric double layer capacitor is mounted on an electric motor vehicle
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A power converting apparatus for electric motor vehicle propulsion is provided that is suitable for a use in which power regeneration from an inverter unit 30 to a power storing unit 50 or power supply from the power storing unit 50 to the inverter unit 30 is frequently used. The power converting apparatus for electric motor vehicle propulsion includes a converter unit 10 that receives input of a power supply voltage from the outside, converts the power supply voltage into a direct current of a predetermined value, and outputs the direct current, the inverter unit 30 that is connected to an output side of the converter unit 10 and drives an electric motor 40, and the power storing unit 50 that is connected to the output side of the converter unit 10. A converter control unit 14 included in the converter unit 10 generates a current command for the converter unit 10 and controls charging and discharge currents to and from the power storing unit 50 based on this current command.