Force Commutated Synchronous Rectifier Bi-Directional Converter
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Solution Overview
Problem
Existing bi-directional voltage converters face inefficiencies due to reverse recovery times in diodes, leading to high power dissipation and weight issues in thermal management, particularly in high-voltage applications.
Innovation Solution
The use of two force commutated synchronous rectifiers eliminates reverse recovery time by commutating currents during switch-off, allowing power to flow efficiently in both directions without a series diode, reducing FET losses and thermal management needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a series diode is used in the converter circuit, then the circuit structure is simpler, but the power dissipation increases and efficiency decreases
Solution Approach 1:
The patent removes the series diode from the converter circuit entirely, replacing it with a synchronous rectifier configuration using FETs. This extraction of the problematic component eliminates the reverse recovery time issue and associated power losses while maintaining circuit functionality through alternative switching mechanisms.
Solution Approach 2:
The patent substitutes the passive diode rectification mechanism with an active FET-based synchronous rectification system. This replacement uses controlled electronic switching instead of passive component behavior, enabling bidirectional power flow and eliminating the inherent limitations of diode-based rectification.
2Productivity
If a series diode is used for rectification, then the rectification function is achieved, but reverse recovery time causes efficiency losses
Solution Approach 1:
The patent applies preliminary action by turning off the FET switch before the current naturally would reverse direction, and using a commutation circuit to actively reverse the current flow. This proactive approach prevents the reverse recovery phenomenon entirely by controlling the switching timing and current direction actively, rather than passively accepting the diode's natural behavior.
Solution Approach 2:
The patent replaces the passive diode rectification mechanism with an active FET-based synchronous rectification system. This substitution uses controlled electronic switching to achieve rectification without the reverse recovery time limitation inherent in diode-based systems.
3Temperature
If high power dissipation occurs in the converter, then thermal management hardware is required, but the weight of the system increases
Solution Approach 1:
The patent removes the source of excessive heat generation by eliminating the series diode and its associated power losses. By replacing it with a synchronous rectifier using low-loss FETs, the system generates significantly less heat, thereby reducing or eliminating the need for heavy thermal management hardware.
Solution Approach 2:
The patent substitutes the high-loss diode-based rectification with a low-loss FET-based synchronous rectification system. This substitution dramatically reduces power dissipation and heat generation, thereby reducing the requirements for thermal management hardware and associated weight.
4Adaptability or versatility
If the converter supports bidirectional power flow, then versatility is improved, but circuit complexity increases
Solution Approach 1:
The patent applies universality by designing a converter circuit that can operate in multiple modes (power factor correction, bidirectional power flow, different voltage levels) using the same basic FET-based synchronous rectifier topology. This multi-functional design achieves versatility without proportionally increasing complexity, as the core switching mechanism serves multiple purposes.
Solution Approach 2:
The patent replaces the unidirectional diode-based rectification with a bidirectional FET-based synchronous rectification system. This substitution enables natural bidirectional power flow capability inherent in the FET switching mechanism, allowing the converter to operate in multiple modes without requiring separate circuits for each function.
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 approach enhances efficiency, reduces weight, and allows for more compact packaging by minimizing heat sink requirements, enabling effective bi-directional power processing in high-voltage systems like spacecraft electrical bus regulation.
Implementation Method 1
The first force commutated synchronous rectifier is operable to eliminate reverse recovery time in a diode by force commutating a commutation current from a cathode terminal of the diode to an anode terminal of the diode while switching off a component associated with the diode
Implementation Method 2
An inductor is charged by the charge current, and a discharge current from the inductor is controlled by the second force commutated synchronous rectifier
Data Source
AI summary
A system and method for bi-directional voltage conversion are disclosed. A charge current is received at a first voltage on a first force commutated synchronous rectifier, and the charge current is controlled by the first force commutated synchronous rectifier. An inductor is charged by the charge current, and a discharge current from the inductor is controlled by the second force commutated synchronous rectifier.