Power Control Apparatus for Harmonic Suppression in Image Forming
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Solution Overview
Problem
Conventional power control techniques face difficulties in effectively suppressing harmonic generation, particularly when the temperature sampling period is long, leading to insufficient harmonic reduction.
Innovation Solution
A power control apparatus that adjusts the current amount by setting a portion of the phase range in each half-wave period as a conduction angle and the remainder as a non-conduction angle, with a distribution processor determining distributed conduction angles across multiple periods to maintain an average within ±2.5% of the reference value, thereby reducing harmonic generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional power control technique with constant conduction angle distribution is used, then the control system is simple, but harmonic suppression is insufficient especially when temperature sampling period is long
Solution Approach 1:
The patent applies dynamics by making the conduction angle distribution variable rather than constant. The distribution processor dynamically adjusts the conduction angle for each half-wave period based on a predetermined distribution pattern, transforming the static control system into a dynamic one that actively suppresses harmonics while maintaining simplicity.
Solution Approach 2:
The patent implements periodic action by distributing the conduction angle differently across multiple half-wave periods within each temperature sampling period. The distribution processor applies a periodic distribution pattern that cycles through different conduction angle allocations, creating a periodic modulation effect that suppresses harmonic generation while maintaining the overall average conduction angle.
2Object-generated harmful factors
If conduction angle is distributed across multiple periods, then harmonic suppression is improved, but the control processing becomes more complex
Solution Approach 1:
The patent applies preliminary action by pre-storing multiple conduction angle distribution patterns in memory before the temperature sampling period begins. The distribution processor simply retrieves and applies the predetermined pattern during operation, avoiding complex real-time calculations and reducing processing complexity while maintaining effective harmonic suppression.
Solution Approach 2:
The patent implements parameter changes by varying the conduction angle parameter across different half-wave periods according to a predetermined distribution pattern. Instead of complex control logic, the system changes the conduction angle parameter in a structured manner that suppresses harmonics while keeping the control processing simple through parameter modulation.
3Object-generated harmful factors
If the conduction angle distribution is updated frequently, then harmonic suppression effectiveness is improved, but the response time for temperature control increases
Solution Approach 1:
The patent applies periodic action by updating the conduction angle distribution pattern periodically at each temperature sampling period rather than continuously. This periodic update approach maintains harmonic suppression effectiveness within each period while avoiding excessive updates that would delay the overall temperature control response.
Solution Approach 2:
The patent implements partial action by applying conduction angle distribution only within each temperature sampling period rather than continuously adjusting it. This partial application of distribution processing achieves sufficient harmonic suppression for each sampling interval without the overhead of continuous adjustment, preserving temperature control response time.
Data Source
AI summary
A power control apparatus that supplies an AC current to a load and adjusts a current amount by setting a portion of a phase range among each of half-wave periods of the AC current to be supplied as a conduction angle and setting the remainder as a non-conduction angle, includes: a reference value determiner that defines a period across a plurality of half-wave periods as a current determination period and that determines a reference value of the conduction angle; and a distribution processor that determines a distribution value to distribute the conduction angle and performs current amount adjustment by distributed conduction angles, wherein the distribution processor determines the distribution value within one current determination period such that the value includes a positive distribution value and a negative distribution value, and an average value of the distributed conduction angles is within ±2.5% with respect to the reference value.