DC/DC Converter Mode Switching for Low-Load NVH Control
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Solution Overview
Problem
Conventional DC/DC converters in electric vehicles do not maintain high efficiency and low noise, vibration, and harshness (NVH) during operation at light loads.
Innovation Solution
A DC/DC converter system with a controller that operates transistors in different modes based on load current, including continuous switching, pulse width modulation (PWM), and burst modes to reduce NVH, especially at low currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional DC/DC converters operate at light loads, then power consumption is reduced, but noise, vibration, and harshness (NVH) increase
Solution Approach 1:
The DC/DC converter dynamically switches between different operating modes (continuous conduction mode and discontinuous conduction mode) based on the load current level. This dynamic adaptation allows the system to maintain low NVH at light loads while preserving adequate efficiency, directly resolving the contradiction between power consumption and harmful factors.
Solution Approach 2:
The converter changes its operating parameters by transitioning between continuous and discontinuous conduction modes. This parameter change enables the system to optimize performance across different load conditions, specifically reducing NVH at light loads while maintaining acceptable power consumption characteristics.
2Loss of energy
If DC/DC converters operate in continuous switching mode at all loads, then efficiency is maintained, but noise and vibration increase at light loads
Solution Approach 1:
The system dynamically adjusts its switching behavior based on load conditions. At light loads, it transitions to discontinuous conduction mode to reduce NVH, while at higher loads it operates in continuous mode to maintain efficiency. This dynamic approach resolves the contradiction between maintaining efficiency and reducing harmful factors.
Solution Approach 2:
The converter changes its conduction mode parameter based on load current thresholds. By switching between continuous and discontinuous modes, it optimizes the balance between energy efficiency and NVH performance across different operating conditions.
3Object-affected harmful factors
If DC/DC converters reduce switching frequency at light loads, then noise and vibration are reduced, but efficiency decreases
Solution Approach 1:
Rather than simply reducing switching frequency, the system dynamically changes its conduction mode to discontinuous mode at light loads. This approach reduces NVH while maintaining better efficiency compared to frequency reduction methods, as the converter continues to switch effectively when needed.
Solution Approach 2:
The converter changes its operational parameters by entering discontinuous conduction mode at light loads, which naturally reduces switching activity and NVH while maintaining adequate efficiency through optimized switching when required.
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 reduces noise, vibration, and harshness while maintaining efficiency by dynamically adjusting transistor operation based on load current levels.
Implementation Method 1
a direct current to direct current converter (DC/DC converter) that regulates and converts one voltage level of direct current to another voltage level
Data Source
AI summary
An electrical system includes a DC/DC converter having a first transistor and a second transistor and a controller. The converter is configured to supply an output voltage to a load. The controller is configured to operate the first and second transistors in a set of modes. When an electrical current drawn by the load is associated with a low electrical current, the set of modes is configured to reduce noise, vibration, and harshness by operating the first and second transistors in a continuous switching mode when the current drawn by the load exceeds a first threshold, operating the first and second transistors in a PWM mode when the current drawn by the load is less than the first threshold and greater than a second threshold, and operating the first and second transistors in a burst mode when the current drawn by the load is less than the second threshold.