Starting Voltage Module Step-Down Converter for Starter Systems
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Solution Overview
Problem
Internal combustion engine starters experience high electrical currents during starting, leading to excessive load on the voltage source and risk of magnetic oversaturation and voltage dips in the on-board voltage system, resulting in inefficiency and safety concerns.
Innovation Solution
A starting voltage module with a step-down converter reduces the starter voltage using MOSFET switches and a control unit to manage current flow, avoiding energy losses and overloading the voltage source, and integrating the module into the vehicle replaces conventional voltage sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional voltage source directly supplies high current to the starter, then the starter can be energized, but the voltage source experiences excessive loading and voltage dips occur in the on-board voltage system
Solution Approach 1:
A step-down converter is introduced as an intermediary device between the voltage source and the starter. This converter includes switching elements (MOSFETs), an inductor, and a capacitor that work together to convert the high voltage from the voltage source into the appropriate lower voltage for the starter, thereby preventing excessive current draw and voltage dips while still delivering the required power.
Solution Approach 2:
The step-down converter dynamically changes voltage and current parameters through controlled switching of MOSFETs. By adjusting the duty cycle of the switching elements and utilizing the energy storage properties of the inductor and capacitor, the converter transforms the voltage source output parameters to match the starter requirements, eliminating the direct high-current connection that causes loading problems.
2Force
If high current flows through the starter winding, then the starter generates sufficient torque, but magnetic oversaturation occurs reducing efficiency
Solution Approach 1:
The step-down converter acts as an intermediary that controls the current delivery to the starter. By using pulse-width modulation through the switching elements and energy storage components, it delivers the precise current needed for optimal torque generation without exceeding the magnetic saturation point of the starter winding, thus maintaining high efficiency.
Solution Approach 2:
The converter uses periodic switching of the MOSFETs to deliver current in controlled pulses rather than continuous high current. This periodic action allows the magnetic field in the starter winding to build up and collapse efficiently, preventing saturation while maintaining the average torque output needed for engine starting.
3Reliability
If a step-down converter is integrated into the starting voltage module, then voltage source loading is reduced and safety is improved, but device complexity increases
Solution Approach 1:
The step-down converter is merged with the voltage source to form an integrated starting voltage module. This combination consolidates the voltage source, switching elements, inductor, capacitor, and control circuitry into a single modular unit, which reduces the overall system complexity compared to having separate components distributed throughout the vehicle's electrical system.
Solution Approach 2:
The integrated starting voltage module serves multiple functions: it acts as the voltage source, contains the step-down converter for voltage regulation, provides current control for the starter, and incorporates protection circuits for voltage safety. This multi-functionality reduces the need for separate dedicated components, thereby managing complexity while achieving multiple objectives.
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 solution provides efficient starting operations with reduced load on the voltage source, enhancing safety and allowing for smaller, cost-effective voltage sources, suitable for hybrid vehicles by preventing voltage dips and ensuring ASIL capability.
Implementation Method 1
a step-down converter between the voltage source and the first potential connection for providing a starter voltage that is reduced with respect to the supply voltage
Implementation Method 2
a converter inductor having a first converter inductor terminal and a second converter inductor terminal
Implementation Method 3
a capacitor unit having a first capacitor unit connection and a second capacitor unit connection
Data Source
Figure 1
AI summary
A starting voltage module for a starter system of an internal combustion engine in a vehicle comprises a voltage source (20) for providing a supply voltage, a ground potential connection (26) for connecting the starting voltage module (16) to a ground potential (28), a first potential output connection (30) for connecting the starting voltage module (16) to a starter system (12) of an internal combustion engine, and a step-down converter (40) between the voltage source (20) and the first potential connection (30) for providing a starter voltage at the first potential connection (30) that is reduced with respect to the supply voltage.