Transformer-Based Variable Voltage Converter for Low Ripple Current
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Solution Overview
Problem
Existing high-power variable voltage converters for electrified vehicles face challenges in maintaining low battery ripple current across a wide range of battery internal impedance changes, requiring large inductance and capacitance that increase volume, weight, cost, and loss, and complicating cooling and packaging.
Innovation Solution
A transformer-based variable voltage converter with a series-connected transformer and input capacitor in parallel with the battery, which reduces inductance and capacitance, using a transformer to limit battery ripple current, maintaining low ripple current regardless of battery internal impedance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If large inductance and capacitance are used to maintain low battery ripple current across wide impedance changes, then battery ripple current is reduced, but volume, weight, cost, and loss increase
Solution Approach 1:
The patent changes the topological parameters of the converter by introducing a transformer with specific turns ratio and connecting the input capacitor in series with the transformer primary winding. This parameter change allows the system to achieve low battery ripple current with significantly reduced inductance and capacitance values compared to conventional parallel LC configurations.
Solution Approach 2:
The transformer acts as an intermediary element between the input capacitor and the rest of the circuit. By introducing this intermediate component with its magnetic coupling and turns ratio, the patent enables indirect impedance transformation that effectively limits battery ripple current without requiring large energy storage components.
2Object-generated harmful factors
If large inductance and capacitance are used to maintain low battery ripple current across wide impedance changes, then battery ripple current is reduced, but weight increases
Solution Approach 1:
The patent changes the topological parameters of the converter by introducing a transformer with specific turns ratio and connecting the input capacitor in series with the transformer primary winding. This parameter change allows the system to achieve low battery ripple current with significantly reduced inductance and capacitance values compared to conventional parallel LC configurations.
Solution Approach 2:
The transformer acts as an intermediary element between the input capacitor and the rest of the circuit. By introducing this intermediate component with its magnetic coupling and turns ratio, the patent enables indirect impedance transformation that effectively limits battery ripple current without requiring large energy storage components.
3Object-generated harmful factors
If large inductance and capacitance are used to maintain low battery ripple current across wide impedance changes, then battery ripple current is reduced, but cost increases
Solution Approach 1:
The patent changes the topological parameters of the converter by introducing a transformer with specific turns ratio and connecting the input capacitor in series with the transformer primary winding. This parameter change allows the system to achieve low battery ripple current with significantly reduced inductance and capacitance values compared to conventional parallel LC configurations.
4Object-generated harmful factors
If large inductance and capacitance are used to maintain low battery ripple current across wide impedance changes, then battery ripple current is reduced, but cooling and packaging complexity increases
Solution Approach 1:
The patent changes the topological parameters of the converter by introducing a transformer with specific turns ratio and connecting the input capacitor in series with the transformer primary winding. This parameter change allows the system to achieve low battery ripple current with significantly reduced inductance and capacitance values compared to conventional parallel LC configurations.
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 achieves low battery ripple current with significant changes in battery internal impedance, reducing volume, loss, and cost, and simplifying cooling and packaging, while maintaining efficient performance across varying temperature conditions.
Implementation Method 1
a transformer having a pair of windings sharing a common terminal
Implementation Method 2
an input capacitor, and an inductor electrically between the switches and transformer
Data Source
AI summary
A vehicle electric drive includes a battery, an electric machine, and a variable voltage converter. The variable voltage converter includes switches, a transformer having a pair of windings sharing a common terminal with a series connected input capacitor, and an inductor electrically between the switches and transformer. The transformer and input capacitor are in parallel with the battery. The variable voltage converter is configured to boost voltage of the battery via operation of the switches.