Bidirectional DC-DC Regenerative Power Management for DC Bus Quality
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Solution Overview
Problem
Conventional methods for managing regenerative power in hybrid vehicles' high voltage DC power systems inadequately harvest regenerative energy, leading to reduced power quality on the DC bus during load transients and requiring additional thermal management due to power dissipation.
Innovation Solution
A regenerative load electric power management system incorporating bidirectional solid state power controllers and bidirectional DC-DC converters, along with an energy storage bus, to efficiently capture and store regenerative energy, improving power quality and reducing thermal management needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If shunt regulators are used to dissipate regenerative power into a power dissipation resistor, then regenerative power can be managed, but additional thermal management is required to manage heat generated in the dissipation resistor
Solution Approach 1:
The patent converts the harmful regenerative power that would otherwise be dissipated as waste heat into useful energy by redirecting it to an energy storage device (battery or capacitor). The regenerative power from motor deceleration is captured and stored, transforming a waste heat problem into an energy recovery opportunity, thereby eliminating the need for thermal management of dissipation resistors.
Solution Approach 2:
The patent introduces an intermediary energy storage device (battery or capacitor) between the regenerative power source and the system bus. This intermediary captures and stores the regenerative energy, preventing it from being dissipated as heat in a resistor and enabling its later reuse when needed.
2Temperature
If regenerative power is redirected to a power sink such as ancillary electrical loads or starter/generator, then thermal management needs are reduced, but current methods do not adequately harvest regenerative energy and can result in reduction in power quality on the DC bus during load transients
Solution Approach 1:
The patent introduces an energy storage device as an intermediary between the regenerative power source and the system bus. This intermediary efficiently captures and stores regenerative energy during braking events, preventing energy loss while maintaining power quality on the DC bus during load transients by providing supplemental power when needed.
Solution Approach 2:
The patent changes the operational parameters of the power management system by introducing energy storage capability, which enables the system to capture regenerative energy at one parameter state (braking) and deliver it at another parameter state (acceleration or high load), thereby improving overall energy harvesting efficiency and power quality.
3Device complexity
If conventional power management methods are used, then system simplicity is maintained, but regenerative energy harvesting is inadequate and power quality deteriorates during load transients
Solution Approach 1:
The patent makes the power management system multi-functional by enabling it to both manage power distribution and harvest regenerative energy through the energy storage device. The system can operate in multiple modes: normal power distribution, regenerative braking energy capture, and supplemental power delivery during transients, thereby improving energy harvesting without proportionally increasing complexity.
Solution Approach 2:
The patent implements preliminary action by pre-charging the energy storage device during normal operation and braking events, so that energy is already available when needed during load transients. This preliminary energy storage prevents power quality deterioration without requiring complex real-time power management interventions.
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 system effectively captures regenerative energy, enhancing power quality on the DC bus and providing fault-tolerant operation by storing energy during transients, while maintaining low weight, size, and cost.
Implementation Method 1
a bidirectional DC-DC converter coupled to the second bidirectional solid state power controller and an energy storage bus coupled to the bidirectional DC-DC converter, the energy storage bus providing access to an energy storage device
Data Source
AI summary
A regenerative load electric power management system can include a system bus, an input filter coupled to the system bus, a first bidirectional solid state power controller coupled to the system bus, a motor drive inverter coupled to the input filter, a second bidirectional solid state power controller coupled to the motor drive inverter, a bidirectional direct current DC-DC converter coupled to the second bidirectional solid state power controller and an energy storage bus coupled to the bidirectional DC-DC converter, the energy storage bus providing access to an energy storage device.