Vehicle Charger Power Factor Correction Circuit Synchronization

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Solution Overview

Problem

Conventional power factor correction circuits in vehicle chargers face issues with electromagnetic noise due to fixed switching frequencies, leading to pulsating input AC current when the switching frequency variation interferes with the input AC voltage frequency.

Innovation Solution

An apparatus that includes a phase angle detection unit and a frequency determination unit to synchronize the switching frequency variation with the input AC voltage period, using a dq phase locked loop structure and cosine calculation to derive the switching frequency, ensuring the switching frequency follows the AC voltage period and preventing input AC current pulsation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the switching frequency of the switching element is varied at a predetermined period within a predetermined range, then electromagnetic noise is distributed over a predetermined band, but the input AC current pulsates due to interference with the input AC voltage frequency

Engineering Contradiction:

Improveelectromagnetic noiseVSAvoidinput AC current pulsation

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The switching frequency is made dynamic by synchronizing its variation period with the input AC voltage frequency. The control apparatus adjusts the switching frequency within a predetermined range while maintaining synchronization with the AC voltage period, preventing current pulsation while still distributing electromagnetic noise across a frequency band.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The switching frequency parameter is varied within a predetermined range (e.g., 85-115 kHz) while maintaining synchronization with the input AC voltage frequency. This parameter change distributes electromagnetic noise energy across a broader spectrum while the synchronized variation prevents constructive interference that would cause current pulsation.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If the switching frequency is fixed, then the power factor correction circuit operates stably, but substantial electromagnetic noise occurs due to narrowband peak component

Engineering Contradiction:

Improveoperational stabilityVSAvoidelectromagnetic noise

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The switching frequency is varied periodically within a predetermined range while maintaining synchronization with the input AC voltage frequency. This periodic variation distributes the narrowband peak component across a broader frequency spectrum, reducing electromagnetic noise while maintaining stable power factor correction operation.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The switching frequency transitions from a fixed value to a dynamically varied value that changes periodically within a predetermined range. This dynamic adjustment disperses electromagnetic noise energy while the control apparatus ensures stable operation by maintaining synchronization with the AC voltage period.

Inventive Principle:

Principle #15Dynamics

3Object-affected harmful factors

If the switching frequency variation period is not synchronized with the input AC voltage period, then electromagnetic noise is distributed, but the input AC current pulsates

Engineering Contradiction:

Improveelectromagnetic noise distributionVSAvoidpower factor correction efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The control apparatus uses feedback from the input AC voltage frequency to synchronize the switching frequency variation period. By detecting the AC voltage period and adjusting the switching frequency variation accordingly, the system achieves both electromagnetic noise distribution and efficient power factor correction without current pulsation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The switching frequency parameter is adjusted based on the input AC voltage frequency. The variation period and range are modified dynamically to maintain synchronization with the AC voltage, ensuring both noise distribution and optimal power factor correction performance.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11658565B2Apparatus for controlling power factor correction circuit of charger for vehicle battery

Publication Date: 2023.05.23 HYUNDAI MOTOR CO LTD

AI summary

An apparatus for controlling a power factor correction circuit of a charger for charging a vehicle batter is configured to correct a power factor of an input AC voltage through switching of a switching element. The apparatus for controlling the power factor correction circuit includes: a phase angle detection unit configured to detect phase angle information of the input AC voltage; and a frequency determination unit configured to synchronize a period in which a preset frequency variation value varies, with a period of the input AC voltage by applying the phase angle information to the frequency variation value, and determine, as a switching frequency of the switching element, a value obtained by applying the synchronized frequency variation value to a preset fundamental frequency value.