DC Converter Voltage Control for Vehicle Driving Motor
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Solution Overview
Problem
Existing methods for controlling the output voltage of a low voltage DC-DC converter in hybrid electric vehicles do not effectively account for road conditions, leading to inefficiencies in charging and discharging the auxiliary battery, particularly during changes in road gradient and curvature, resulting in wasted regenerative braking energy.
Innovation Solution
A method and apparatus that determine the expected state of charge (SOC) of the auxiliary battery at specific event points on the driving route, adjusting the output voltage of the DC converter based on SOC difference values, with discharging-oriented or charging-oriented controls set according to negative or positive SOC differences, and a maximum output voltage when a main battery discharging condition is met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the output voltage of the LDC is adjusted based on current driving mode and SOC of the auxiliary battery, then the auxiliary battery can be efficiently charged or discharged at current time, but it does not completely reflect road conditions (gradient, curvature radius) and is inefficient in consideration of entire driving section
Solution Approach 1:
The controller pre-calculates the expected SOC at event points along the driving route before actually reaching them. By determining the SOC trajectory in advance based on road gradient, curvature radius, and traffic conditions, the system prepares charging/discharging strategies proactively rather than reactively, enabling efficient energy management throughout the entire driving section.
Solution Approach 2:
The system continuously monitors the actual SOC and compares it with the expected SOC at event points. Based on the SOC difference value, the controller dynamically adjusts the output voltage of the LDC to maintain optimal charging/discharging operations, creating a closed-loop feedback mechanism that adapts to actual driving conditions.
2Loss of energy
If the SOC of the auxiliary battery is high when entering a downhill, then the chargeable SOC is insufficient, resulting in wasted regenerative braking energy
Solution Approach 1:
The controller identifies downhill event points in advance along the driving route and calculates the expected SOC at these points. By knowing the future road gradient conditions beforehand, the system can proactively manage the auxiliary battery SOC to ensure sufficient chargeable capacity before regenerative braking opportunities arise, preventing energy waste.
Solution Approach 2:
The system takes preliminary actions to prevent the problem of insufficient chargeable SOC before it occurs. By monitoring upcoming downhill sections and adjusting charging strategies in advance, the controller ensures the auxiliary battery is in an optimal state to capture regenerative braking energy, counteracting the potential energy loss before the downhill event occurs.
3Device complexity
If the output voltage of the DC converter is determined without considering event points on the driving route, then the control is simpler, but the charging and discharging management is inefficient across the entire driving section
Solution Approach 1:
The driving route is divided into multiple segments with event points (acceleration, deceleration, uphill, downhill) identified at specific locations. The controller calculates expected SOC at each event point separately and determines output voltage strategies for each segment, enabling precise power management throughout the entire driving section rather than using a single uniform control approach.
Data Source
AI summary
A method and an apparatus are provided for controlling an output voltage of a direct current (DC) converter for a vehicle including a driving motor. The apparatus of controlling an output voltage of a DC converter for a vehicle including a driving motor includes a data detector that is configured to detect data for adjusting the output voltage of the DC converter and a controller that is configured to adjust the output voltage of the DC converter based on the detected data.