Power Inverter Boost Converter Functionality
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Solution Overview
Problem
Hybrid electric or battery electric vehicles often require additional DC-DC converters to step up voltage from an off-board power source during charging, leading to increased cost, mass, and volume due to native onboard rechargeable energy storage systems storing higher voltage than available from the charging source.
Innovation Solution
An electrical system that utilizes a power inverter and machine windings to provide boost converter functionality by selectively transitioning switches between open and closed states, allowing current flow from an off-board power source through the machine windings to the rechargeable energy storage system, thereby stepping up the voltage, and includes semiconductor switches and an inductor to mitigate current and torque ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional DC-DC converters are added to step up voltage from off-board power source, then voltage conversion capability is improved, but vehicle weight, cost, and volume increase
Solution Approach 1:
The patent combines the DC-DC converter functionality with the existing power inverter by sharing semiconductor switches and machine windings. The power inverter's existing components are utilized to perform both AC conversion and DC voltage boosting functions, eliminating the need for a separate DC-DC converter and reducing overall system weight.
Solution Approach 2:
The power inverter is designed to perform multiple functions: converting DC from the RESS to AC for the traction motor, and simultaneously functioning as a DC-DC converter to step up voltage from off-board power sources during charging. This multi-functionality eliminates the need for dedicated separate converters.
2Adaptability or versatility
If additional DC-DC converters are added to step up voltage from off-board power source, then voltage conversion capability is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges the DC-DC converter circuit with the power inverter circuit, sharing semiconductor switches, machine windings, and control electronics. This consolidation reduces component count and manufacturing complexity, thereby lowering production costs.
Solution Approach 2:
By designing the power inverter to handle both motor drive and charging functions, the system eliminates the need for separate dedicated DC-DC converter components, reducing bill of materials costs and assembly expenses.
3Adaptability or versatility
If additional DC-DC converters are added to step up voltage from off-board power source, then voltage conversion capability is improved, but system volume increases
Solution Approach 1:
The patent integrates the DC-DC converter functionality within the existing power inverter housing and structure, sharing physical space for components such as semiconductor switches, inductors, and control circuits. This eliminates the need for additional dedicated space and reduces overall system volume.
Solution Approach 2:
The power inverter is engineered to serve dual purposes: driving the traction motor and charging the RESS from off-board sources. This multi-functional design eliminates the need for separate physical converter units, reducing system volume.
4Power
If switch transitions between open and closed states to allow current flow through machine windings, then voltage stepping up is achieved, but torque ripple and current ripple occur
Solution Approach 1:
The patent introduces an inductor as an intermediary component in the DC-DC converter circuit. This inductor acts as a mediator that smooths the current flow during switch transitions, reducing current ripple and consequently minimizing torque ripple in the machine windings while maintaining voltage boosting capability.
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 eliminates the need for additional DC-DC converters, reducing vehicle weight, cost, and volume by integrating boost converter functionality within the existing electrical system, while ensuring efficient voltage stepping and minimizing torque disturbance during charging.
Implementation Method 1
Semiconductor switches of a power inverter module are controlled via pulse-width modulation or other switching control signals to convert the battery output voltage to an alternating current (AC) output voltage
Implementation Method 2
the inductor is configured to mitigate at least one of current ripple or torque ripple
Data Source
AI summary
An example electrical system is disclosed. The electrical system can include a rechargeable energy storage system (RESS) and a power inverter connected to the RESS. The power inverter can be configured to provide electrical power to a traction motor. The electrical system can include a plurality of machine windings connected between the power inverter and a switch. The switch can be configured to transition between a closed state to allow current flow from an off-board power source through the plurality of machine windings to the RESS and an open state to prevent current flow between the off-board power source and the plurality of machine windings.