Power converter
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Solution Overview
Problem
Existing power converters in motor drivers experience noise generation and loss due to switching operations, particularly with wide bandgap semiconductors, and existing snubber circuits introduce additional losses by allowing charge and discharge currents during normal operation.
Innovation Solution
A power converter design incorporating a snubber circuit with a first diode and capacitor in parallel with the reactor, directing recovery currents away from the switching element to the AC power supply, reducing noise and loss by providing an alternative path for recovery currents and using wide bandgap semiconductors for efficient switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a snubber circuit consisting of diodes and a capacitor is provided in parallel with a switching element to absorb recovery current and reduce noise, then noise is reduced, but charge and discharge currents flow through the snubber circuit during normal switching operation causing loss
Solution Approach 1:
The patent extracts the harmful recovery current from the main switching path by providing a dedicated circulation path through the snubber circuit. The first diode is configured to allow recovery current to circulate between the capacitor and the switching element, preventing it from flowing through the load or causing noise, while the second diode prevents normal load current from entering the snubber circuit.
Solution Approach 2:
The snubber circuit acts as an intermediary element between the switching element and the load. It mediates the recovery current by providing a controlled circulation path that isolates the recovery current from the main power flow, allowing noise reduction without interfering with normal switching operation.
2Loss of energy
If wide bandgap semiconductors are used for switching elements to reduce switching loss and improve switching characteristic, then switching loss is reduced, but noise is likely to be generated by ringing and recovery current
Solution Approach 1:
The patent converts the harmful recovery current and ringing noise into a beneficial circulation pattern. By providing a dedicated path through the first diode and capacitor, the recovery current that would otherwise cause noise is redirected to circulate harmlessly, transforming a harmful effect into a controlled, noiseless operation.
Solution Approach 2:
The snubber circuit serves as an intermediary that handles the noisy recovery current generated by wide bandgap semiconductors, allowing these high-performance switching elements to operate at full efficiency without transmitting noise to the load or system.
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 converter effectively reduces noise and loss by managing recovery currents through a snubber circuit, stabilizing ground potential and improving detection accuracy, while utilizing wide bandgap semiconductors for efficient switching and reduced size and heat dissipation.
Implementation Method 1
The switching element performs power supply short-circuiting operation to short-circuit the output path of the rectification circuit upon transition to a conductive state. This power supply short-circuiting operation increases the current flowing in the reactor, thereby the reactor charges energy.
Implementation Method 2
When the voltage at the reactor exceeds the terminal voltage of the capacitor, the reverse blocking diode transitions to a conductive state, thereby causing a current to flow from the reactor to the capacitor, and the capacitor is thus charged.
Implementation Method 3
Opening the switching element under this condition decreases the current flowing to the reactor, and accordingly generates a voltage across the reactor based on a relationship of V=Ldi/dt.
Data Source
AI summary
A power converter is connected between a power supply source of a first direct current power and a power supply destination of a second direct current power obtained by performing power conversion on the first direct current power. The power converter includes: a switching element; a reactor; a first diode; a first capacitor; a second diode. The reactor is connected to a first end of the switching element. The first end of the switching element and a first end of the reactor are connected to a first connection point. A cathode of the first diode is connected to a second end of the reactor. The cathode of the first diode and the second end of the reactor are connected to a second connection point. The second diode includes an anode connected to the first connection point and a cathode connected to the power supply destination.