H-Bridge Bootstrap Circuit Energy Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional H-bridge power factor correction (PFC) circuits face operational reliability issues due to loss of the bootstrap path during unloaded conditions, light loads, or zero-crossings of AC input voltage, leading to insufficient voltage across the bootstrap capacitor, which affects the driving circuit's ability to operate effectively.
Innovation Solution
An H-bridge circuit with an energy compensation circuit and a controlling method that provides compensation energy to the bootstrap circuit when the bootstrap voltage is insufficient, ensuring the operational reliability by comparing the bootstrap voltage with a reference voltage and controlling a switch element to supply energy when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bootstrap driver circuit is used in the H-bridge circuit, then the circuit structure is simple and easy to manufacture, but the bootstrap path is lost during unloaded conditions, light loads, or zero-crossings of AC input voltage, leading to insufficient bootstrap capacitor voltage and reduced operational reliability
Solution Approach 1:
The energy compensation circuit is designed to proactively detect when the bootstrap capacitor voltage drops below a threshold (during unloaded conditions, light loads, or zero-crossings) and automatically activate to recharge the bootstrap capacitor before the driving circuit fails, preventing the reliability issue before it occurs
Solution Approach 2:
An auxiliary energy compensation circuit is introduced as an intermediary component between the AC power source and the bootstrap capacitor. This mediator circuit includes a switch element, diode, and capacitor that selectively transfers energy to maintain the bootstrap capacitor voltage when the conventional bootstrap path is unavailable, thus resolving the reliability issue without fundamentally changing the main H-bridge circuit structure
2Productivity
If the bootstrap path is lost during unloaded conditions or zero-crossings, then the H-bridge circuit can operate with fewer components, but the driving circuit cannot effectively operate due to insufficient voltage across the bootstrap capacitor
Solution Approach 1:
The energy compensation circuit changes the voltage parameter of the bootstrap capacitor by actively charging it when the voltage drops below a threshold. The circuit monitors the bootstrap capacitor voltage and activates the switch element to transfer energy from the AC power source through the diode to recharge the capacitor, maintaining the voltage parameter within the required range for continuous driving circuit operation
Solution Approach 2:
The bootstrap circuit with energy compensation is designed to be self-regulating. The driving circuit's own operation triggers the need for bootstrap voltage, and when that voltage drops, the system automatically activates the energy compensation mechanism through voltage threshold detection, allowing the circuit to service itself without external intervention
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 energy compensation circuit effectively raises the operational reliability of the bootstrap circuit by maintaining a stable voltage across the bootstrap capacitor, even under conditions where the conventional bootstrap path is lost, thereby ensuring continuous operation of the driving circuit.
Implementation Method 1
a bootstrap circuit providing a bootstrap voltage... a bootstrap capacitor having a first terminal and a second terminal connected to the bidirectional switch, and the bootstrap voltage is a voltage across the bootstrap capacitor
Implementation Method 2
an energy compensation circuit coupled to the H-bridge, the bootstrap circuit and the driving circuit, and providing a compensation energy to the bootstrap circuit
Data Source
AI summary
The configurations of an H-bridge circuit and a controlling method thereof are provided in the present invention. The proposed circuit includes an H-bridge having a first and a second bridge arms, each of which has a middle point, and a bidirectional switch connected to the two middle points, a bootstrap circuit providing a bootstrap voltage, a driving circuit receiving the bootstrap voltage and driving the bidirectional switch, and an energy compensation circuit coupled to the H-bridge, the bootstrap circuit and the driving circuit, and providing a compensation energy to the bootstrap circuit.