Moving-Body Power Supply Bypass Circuit for Lower Switching Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power supply systems for moving bodies, such as electric vehicles, face increased switching loss and steady loss due to the use of multi-stage DC chopper circuits, which require higher withstand voltage switching elements, leading to higher on-resistance and subsequent losses.
Innovation Solution
A power supply system that includes a variable voltage power supply, a first and second power line connecting the power supply to a load, a first switch on the first power line, a bypass line with a bypass diode, and first and second DC power supplies. This configuration allows for reduced switching and steady losses by minimizing the number of switches and lowering the withstand voltage of the switching elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a multi-stage DC chopper circuit is used to generate AC power, then AC power can be supplied to the load, but the number of switching elements increases and switching loss increases
Solution Approach 1:
The invention extracts the DC power supply function from the multi-stage DC chopper circuit and implements it as a separate DC power supply unit. This allows the chopper circuit to use fewer switching elements while still achieving the required multi-level voltage output through the combination of the DC power supply and the chopper circuit's switching action.
Solution Approach 2:
The power conversion function is segmented into two independent parts: a DC power supply unit that provides DC voltage and a chopper circuit that converts DC to AC. This segmentation allows each unit to be optimized independently, reducing the overall complexity and switching loss.
2Reliability
If the withstand voltage of switching elements is increased to handle surge voltage, then reliability improves, but on-resistance increases and steady loss increases
Solution Approach 1:
The invention introduces a DC power supply unit as an intermediary between the battery and the chopper circuit. This DC power supply acts as a buffer that handles voltage stabilization and surge protection, allowing the chopper circuit's switching elements to operate at lower voltages with lower on-resistance while still protecting against surge voltages.
3Loss of energy
If the number of switching elements is reduced to decrease switching loss, then energy efficiency improves, but the ability to generate multi-stage DC voltage may be compromised
Solution Approach 1:
The invention merges the DC power supply function with the chopper circuit by connecting them in series. The DC power supply provides DC voltage and the chopper circuit converts it to AC, creating a unified power conversion system that achieves multi-stage voltage output with fewer switching elements than a traditional multi-stage DC chopper circuit.
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 proposed power supply system reduces switching loss and steady loss compared to multi-stage DC chopper circuits, lowers the withstand voltage of switching elements, and decreases iron loss by minimizing high-frequency voltage components.
Implementation Method 1
a bypass diode (33a) that allows an output current of the first DC power supply and cuts off a current reverse to the output current
Data Source
AI summary
A power supply system 1 includes: a variable voltage power supply 7 that outputs power of a variable voltage E1 from a pair of secondary-side input/output terminals 72p and 72n; a first power line 21 and a second power line 22 that connect the pair of secondary-side input/output terminals 72p and 72n and a load 4; a first switch unit 31 that is provided on the first power line 21; a third power line 23 that connects both ends of the first switch unit 31; and a bypass line 25 that connects the pair of secondary-side input/output terminals 72p and 72n, a first DC power supply 38 is provided on the third power line 23 to output DC power, and a bypass diode 33a is provided on the bypass line 25 to allow an output current of the first DC power supply 38.