Vehicle Boost Converter with Selective Bypass Switch
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Solution Overview
Problem
Conventional DC boost converters in hybrid electric and battery electric vehicles are oversized for peak power consumption, leading to inefficiencies and increased cost, size, and weight, as they are designed to handle maximum power requirements rather than typical operating conditions.
Innovation Solution
Incorporating a bypass switch in the DC boost converter that can be selectively enabled or disabled by a controller based on the operating mode of the vehicle, allowing the converter to be downsized to a lower power rating, such as 30 kW, while maintaining 90% of the fuel economy benefits by bypassing the boost converter during lower power operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the DC boost converter is sized for peak power consumption (90 kW), then the system can handle maximum power requirements, but the converter size, weight, and cost increase
Solution Approach 1:
The patent applies dynamics by making the boost converter configuration dynamic through the bypass switch. The system transitions between two operational states: full boost converter mode for peak power demands and bypass mode for normal operation. This dynamic reconfiguration allows the converter to be physically smaller while maintaining peak power capability when needed.
Solution Approach 2:
The patent segments the power conversion path into two parallel routes: through the boost converter for voltage boosting when needed, and through the bypass switch for direct connection during normal operation. This segmentation allows the system to use only the necessary component (boost converter) only when required, reducing overall system size and weight.
2Power
If the DC boost converter is sized for peak power consumption (90 kW), then the system can handle maximum power requirements, but the converter cost increases
Solution Approach 1:
The dynamic switching configuration allows the system to use a smaller, less expensive boost converter (30 kW) that only needs to handle peak power temporarily. The bypass switch enables normal operation without requiring the converter to be continuously sized for peak demand, reducing manufacturing cost while maintaining peak power capability.
Solution Approach 2:
By segmenting the power path with a bypass option, the system can use a lower-power, lower-cost boost converter for peak conditions while using the bypass switch for normal operation. This eliminates the need to oversize the converter for continuous peak operation, reducing component costs.
3Power
If the DC boost converter is sized for peak power consumption (90 kW), then the system can handle maximum power requirements, but the converter size increases
Solution Approach 1:
The patent uses dynamic control of the bypass switch to enable a smaller boost converter to provide peak power capability only when needed. During normal operation, the bypass switch provides a direct connection, allowing the converter to be physically smaller while maintaining the ability to handle peak power demands.
Solution Approach 2:
The power conversion system is segmented into two paths: a direct bypass path for normal operation and a boost converter path for peak power needs. This segmentation allows the converter to be smaller since it only needs to handle power during specific conditions, not continuously.
4Loss of energy
If the bypass switch is closed to bypass the DC boost converter, then efficiency improves and fuel economy benefits are achieved, but the boosted voltage is not available
Solution Approach 1:
The system dynamically switches between bypass mode (for efficiency during normal operation) and boost mode (for when increased voltage is needed). The controller monitors system conditions and transitions the bypass switch state accordingly, ensuring that the vehicle operates in the most efficient mode while maintaining the capability to provide boosted voltage when required.
Solution Approach 2:
The bypass switch provides a pre-configured alternative path that prevents energy loss through the boost converter during normal operation. By having this alternative path ready and switchable, the system can avoid the inefficiencies of continuous boost converter operation while maintaining the option to use boosting when needed.
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 approach enhances efficiency, reduces the size, weight, and cost of the system by optimizing the boost converter sizing based on typical operating conditions, improving fuel economy and power performance by minimizing the use of the full-sized boost converter during most operating regions.
Implementation Method 1
A DC boost converter includes various electrical circuit components such as capacitors, inductors, and semiconductor switches, with switching of the semiconductor switches ultimately increasing or boosting the voltage level available from the DC battery pack
Implementation Method 2
A DC boost converter includes various electrical circuit components such as capacitors, inductors, and semiconductor switches
Implementation Method 3
Semiconductor switches of a power inverter module are controlled via pulse-width modulation or other switching control signals to convert the boosted battery output voltage from the DC boost converter into an alternating current (AC) output voltage
Implementation Method 4
The controller, via different switching commands, respectively closes or opens the bypass switch depending on the present operating mode of the vehicle. Closing the bypass switch connects the DC battery pack to the input node of the power inverter, thereby bypassing the DC boost converter
Data Source
AI summary
A vehicle includes a transmission, energy storage system (ESS), power inverter module (PIM), and controller. The PIM includes a boost converter having a bypass switch and a first plurality of switches, and also a power inverter having a second plurality of switches. The controller is programmed to execute a method that enables a DC boost converter of the PIM by opening the bypass switch when a speed and a torque of the electric machine are within a predetermined boost range. The controller bypasses the boost converter by transmitting a second switching signal closing the bypass switch when the speed and torque are not within the predetermined boost range. A voltage input to the power inverter is equal to the DC battery voltage whenever the boost converter is bypassed and exceeds the DC battery voltage whenever the boost converter is enabled.