Three-Level DC Converter Control for Flying Capacitor Voltage Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing three-level direct current converters with flying capacitors face challenges in maintaining a stable voltage on the flying capacitor, leading to increased ripple current and additional power loss due to deviations from half the power supply voltage.
Innovation Solution
A three-level direct current converter is designed with an on-time generator that adjusts the charging current of a capacitor to maintain the voltage on the flying capacitor at half the power supply voltage, thereby stabilizing the switch point voltage and reducing ripple current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the voltage on the flying capacitor is not maintained at half the power supply voltage, then the circuit operation is simpler, but the ripple current of the inductor increases and additional power loss occurs
Solution Approach 1:
The patent implements a feedback control mechanism where the control circuit continuously monitors the voltage on the flying capacitor and adjusts the charging current accordingly. When the voltage deviates from half the power supply voltage, the control circuit modifies the on-time signal to correct the voltage, ensuring stable operation and minimizing ripple current and power loss.
Solution Approach 2:
The patent dynamically adjusts the charging current parameter of the on-time generator based on the flying capacitor voltage status. By changing the charging current in response to voltage deviations, the system maintains optimal operating conditions, reducing ripple current and power loss while keeping the circuit operation relatively simple.
2Device complexity
If the voltage on the flying capacitor deviates from half the power supply voltage, then fewer control adjustments are needed, but the switch point voltage becomes unstable and ripple current increases
Solution Approach 1:
The control circuit employs feedback control to monitor the flying capacitor voltage and automatically adjust the charging current through the on-time generator. This maintains the switch point voltage stability without requiring complex manual control adjustments, as the system self-corrects voltage deviations.
Solution Approach 2:
The system performs self-regulation by automatically detecting voltage deviations on the flying capacitor and adjusting its own operating parameters (charging current) through the control circuit. This self-service mechanism maintains voltage stability without external intervention or complex control systems.
3Stability of the object's composition
If the charging current of the on-time generator is adjusted to maintain flying capacitor voltage, then the voltage stability improves, but the control circuit complexity increases
Solution Approach 1:
The control circuit uses feedback control to achieve flying capacitor voltage stability through automatic adjustment of the charging current. The feedback mechanism compares the actual voltage with the target voltage (half the power supply voltage) and generates corrective control signals, maintaining stability without requiring overly complex control architecture.
Solution Approach 2:
The system maintains flying capacitor voltage stability by dynamically changing the charging current parameter of the on-time generator. This parameter adjustment approach provides effective voltage control while keeping the control circuit relatively simple, as it focuses on modifying a single key parameter rather than implementing complex multi-parameter control.
Data Source
AI summary
The three-level direct current converter includes: a flying capacitor, a plurality of switch groups, a drive circuit, and a control circuit. The control circuit includes at least an on-time generator. When a voltage on the flying capacitor deviates from a half of a power supply voltage, the on-time generator changes a charging current of a capacitor of the on-time generator to adjust an output on-time signal, and outputs the on-time signal to the drive circuit. The drive circuit generates a drive pulse signal based on the on-time signal to drive switch statuses of the plurality of switch groups, to adjust charging time and discharging time of the flying capacitor, where an absolute value of a difference between the voltage on the flying capacitor and the half of the power supply voltage is less than or equal to a preset threshold.