Current Resonance Circuit Control Apparatus for DC/DC Converters
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Solution Overview
Problem
Current DC/DC converters with current resonance circuits face instability due to noise influences when controlling output power based solely on integration results, leading to delayed control responses and the need for increased capacitor capacity.
Innovation Solution
A control apparatus and method for a current resonance circuit that includes an integration circuit, feedback circuit, comparison circuit, digital filtering circuit, and PWM circuit to generate a pulse width modulation signal, comparing integration signals with feedback signals and filtering noise to stabilize control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If output power is controlled only according to integration result, then control response is faster, but output voltage varies greatly due to noise influence
Solution Approach 1:
The patent introduces a feedback signal from the output voltage through a feedback circuit, and compares it with the integration signal. This feedback mechanism allows the system to correct for noise-induced variations by continuously monitoring the actual output voltage and adjusting the PWM duty cycle accordingly, thus maintaining control stability while preserving fast response characteristics.
Solution Approach 2:
The patent combines two different control signals (integration signal and feedback signal) into a composite measurement signal through comparison. This composite signal integrates the advantages of both approaches: the fast response from integration and the noise immunity from feedback, creating a robust control signal that resolves the contradiction between speed and reliability.
2Loss of energy
If DC/DC converter uses current resonance circuit, then switching loss is reduced and efficiency is improved, but control response is delayed and capacitor capacity must be increased
Solution Approach 1:
The patent replaces traditional voltage-based control mechanisms with current-based integration and comparison. By integrating the current through the switching element and comparing it with a feedback signal, the system achieves faster and more accurate control response without requiring large capacitors for smoothing, thus reducing both energy loss and time delay.
Solution Approach 2:
The patent changes the control parameter from voltage to current integration. This parameter change enables the system to achieve both low switching loss (through resonant current control) and fast response (through direct current measurement and comparison), resolving the contradiction between energy efficiency and response speed.
3Measurement precision
If integration circuit is used for power control, then control precision is improved, but noise influence increases and control stability deteriorates
Solution Approach 1:
The patent uses feedback to counteract noise effects. The feedback signal, derived from the actual output voltage, provides a reference that cancels out noise components in the integration signal. This allows the system to maintain high measurement precision while achieving stable control by continuously correcting for noise-induced deviations.
Solution Approach 2:
The comparison circuit acts as an intermediary between the integration circuit and the PWM generator. It processes the integration signal by comparing it with the feedback signal, effectively filtering out noise while preserving the precise power control information. This intermediary function resolves the contradiction by separating noise from useful control signals.
Data Source
AI summary
Embodiments of this disclosure provide a control apparatus and method for a current resonance circuit and a current resonance power supply. The control method includes: performing integration on a resonance current of the current resonance circuit or a switching current of one or more switching elements to generate an integration signal; generating a feedback signal of the current resonance circuit; comparing the integration signal with the feedback signal, and generating a measurement signal according to a comparison result; performing digital filtering on the measurement signal; and according to the measurement signal after filtering, generating a pulse width modulation signal controlling the switching elements.