Bidirectional Power Converter Dynamic Voltage Control
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Solution Overview
Problem
Existing power conversion systems face challenges in efficiently managing bidirectional power conversion between primary and secondary sides without DC conversion, particularly in handling varying voltage magnitudes and preventing inrush currents during voltage changes.
Innovation Solution
A power conversion apparatus incorporating matrix converter circuitry, rectifier circuitry, and control circuitry that adjusts the changeover reference voltage based on primary side voltage magnitude, allowing the rectifier circuitry to connect through either a route with a current limit device or one that bypasses it, thereby controlling the connection state for bidirectional power conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rectifier circuitry is always connected through the current limit device, then inrush currents are suppressed, but the response speed to voltage changes is reduced and power conversion efficiency deteriorates
Solution Approach 1:
The patent applies dynamics by making the connection route dynamically switchable between two states: connected through the current limit device when voltage magnitude is below the threshold, and connected directly when voltage magnitude exceeds the threshold. This dynamic switching resolves the contradiction by adapting the connection state to real-time voltage conditions, suppressing inrush currents during normal operation while enabling fast response during voltage sags.
Solution Approach 2:
The patent changes the parameter of connection impedance based on voltage magnitude. When the primary side voltage magnitude exceeds the threshold, the connection impedance is reduced by bypassing the current limit device; when it falls below the threshold, the impedance is increased by connecting through the current limit device. This parameter change resolves the contradiction by optimizing both current suppression and response speed under different operating conditions.
2Speed
If the rectifier circuitry is always connected directly to the capacitor, then response speed is improved, but inrush currents increase and cause harmful effects
Solution Approach 1:
The patent makes the connection state dynamic by switching between direct connection and connection through current limit device based on voltage magnitude. This resolves the contradiction by enabling direct connection (fast response) only when voltage magnitude exceeds the threshold, while using current limit device connection (slow response) when voltage is normal, thus achieving fast response without constant inrush currents.
Solution Approach 2:
The current limit device acts as an intermediary that can be inserted or removed from the connection path. When voltage magnitude is below the threshold, it mediates the connection to suppress inrush currents; when voltage exceeds the threshold, it is bypassed to enable direct connection for fast response. This intermediary mechanism resolves the contradiction by providing conditional current limiting.
3Device complexity
If a fixed changeover reference voltage is used, then the control logic is simple, but the system cannot adapt to varying voltage magnitudes and maintains inrush current suppression unnecessarily
Solution Approach 1:
The patent makes the changeover reference voltage dynamic by setting it equal to the instantaneous primary side voltage magnitude. This resolves the contradiction by allowing the reference voltage to adapt automatically to varying voltage magnitudes, enabling the system to switch to direct connection when voltage sags occur without requiring complex adaptive algorithms, thus maintaining both simplicity and adaptability.
Solution Approach 2:
The patent changes the reference voltage parameter dynamically based on the primary side voltage magnitude. Instead of using a fixed reference voltage, the system sets the reference voltage equal to the instantaneous voltage magnitude, which allows the comparison result to accurately reflect voltage sags and enable appropriate connection switching, resolving the contradiction between simplicity and adaptability.
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 enables efficient bidirectional power conversion across varying voltage conditions, reducing inrush currents and expanding the adaptable power source voltage range, thereby enhancing the system's operational flexibility and efficiency.
Implementation Method 1
rectifier circuitry configured to convert the primary side electric power to charge a capacitor having a terminal voltage
Implementation Method 2
a first connection state in which the rectifier circuitry is connected to the capacitor by a first route including a current limit device
Data Source
AI summary
A power conversion apparatus includes: matrix converter circuitry to perform power conversion between a primary side electric power and a secondary side electric power; rectifier circuitry to convert the primary side electric power to charge a capacitor; and control circuitry to: set a changeover reference voltage at a first reference voltage when the primary side voltage magnitude is a first voltage magnitude and set the changeover reference voltage at a second reference voltage when the primary side voltage magnitude is a second voltage magnitude; and select, based on the changeover reference voltage and the terminal voltage, a connection state from: a first connection state in which the rectifier circuitry is connected to the capacitor by a first route including a current limit device; and a second connection state in which the rectifier circuitry is connected to the capacitor by a second route that bypasses the current limit device.