Power Supply Cell Topology for Smooth Series-Parallel Output Control
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Solution Overview
Problem
Conventional DC to DC power conversion systems face inefficiencies and limited constant output power range when switching between series and parallel connections, especially in wide voltage range applications like electric vehicle charging, where the output current drops significantly when changing from parallel to series connection.
Innovation Solution
A power supply cell and system that utilize a first and second power conversion circuit, controllable unidirectional semiconductor switches, and low-pass filters to control the series and parallel connection ratio, allowing for a wide linearly extended output voltage and current range, with the low-pass filters enhancing filtering power and reducing inductor requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power modules are switched between series and parallel connection to extend output voltage range, then output voltage range is enlarged, but output current drops significantly when changing from parallel to series connection
Solution Approach 1:
The patent applies dynamic switching control between series and parallel connections of power modules. The controlling unit dynamically adjusts the connection configuration based on the required output voltage and current demands, enabling the system to transition smoothly between different operational states. This dynamic approach allows the system to maintain optimal performance across a wide range of output conditions without significant current drops during transitions.
Solution Approach 2:
The patent changes the electrical connection parameters (series/parallel configuration) of power modules to adapt to different output requirements. By modifying the connection topology parameter, the system can extend its output voltage range while the controlling unit compensates for current variations to maintain constant power output. This parameter change approach enables flexible adaptation to wide voltage range applications.
2Ease of manufacture
If conventional DC to DC power conversion is used with series-parallel switching, then cost is reduced, but constant output power range cannot be attained due to step drop in maximum output current
Solution Approach 1:
The patent implements a feedback control mechanism where the controlling unit monitors the output voltage and current conditions and adjusts the switching configuration accordingly. This feedback loop ensures that the system maintains constant power output by compensating for the step drops in maximum output current that occur during series-parallel transitions. The feedback control enables reliable constant power operation across the entire output range while keeping the system cost-effective.
3Adaptability or versatility
If wide output voltage range is required for EV charging applications, then charging compatibility is improved, but power efficiency decreases when operating far from optimal operation point
Solution Approach 1:
The patent employs dynamic operation mode switching that allows the power conversion circuit to operate at or near its optimal efficiency point across a wide voltage range. By dynamically adjusting the connection configuration and control parameters, the system maintains high power efficiency even when operating far from the original optimal point, thereby reducing energy losses while providing wide charging voltage compatibility for different EV types.
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
This solution achieves a smooth and linearly extended output power range, maintaining constant power output from 375V to 1000V, reducing inductor size and cost, and improving power efficiency by controlling the series and parallel connection ratio through PWM modulation.
Implementation Method 1
The first low-pass filter can help smooth an output voltage and current in order to achieve a relatively wide linearly constant output power range
Implementation Method 2
a first controllable unidirectional semiconductor switch operative to generate a first conduction path from the first positive terminal of the first power conversion circuit to the second negative terminal of the second power conversion circuit
Data Source
AI summary
An objective of the disclosure is to provide a power supply cell of a power supply system and a power supply system using the same. The power supply cell includes a first power conversion circuit operative to output a first DC voltage across its first positive terminal and first negative terminal, a second power conversion circuit operative to output a second DC voltage across its second positive terminal and second negative terminal, a first controllable unidirectional semiconductor switch operative to generate a first conduction path from the first positive terminal of the first power conversion circuit to the second negative terminal of the second power conversion circuit, a first unidirectional semiconductor switch operative to generate a second conduction path from the first positive terminal of the first power conversion circuit to the second positive terminal of the second power conversion circuit, a second unidirectional semiconductor switch operative to generate a third conduction path from the first negative terminal of the first power conversion circuit to the second negative terminal of the second power conversion circuit, a first low-pass filter, a second low-pass filter, a third low-pass filter and a controlling unit. The controlling unit is operative to: issue turn-on signal to the first controllable unidirectional semiconductor switch so that the first power conversion circuit and the second power conversion circuit supply current to the first low-pass filter via the first conduction path, the second low-pass filter and the third low-pass filter; or issue turn-off signal to the first controllable unidirectional semiconductor switch so that the first power conversion circuit and the second power conversion circuit supply currents to the first low-pass filter in parallel via the second conduction path and the second low-pass filter together with the third conduction path and the third low-pass filter. The first low-pass filter can help smooth an output voltage and current in order to achieve a relatively wide linearly constant output power range.