Power Adjusting Unit for Transformer Duty Control
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Solution Overview
Problem
Conventional power devices for image forming apparatuses face difficulties in controlling output when load impedance is low and fail to secure sufficient output when load impedance is high, due to significant changes in output voltage in response to duty changes in PWM signals.
Innovation Solution
A power device comprising a transformer with a primary and secondary coil, a control signal outputting unit, and a power adjusting unit that modifies the rate of change of power supplied to the primary coil based on a control signal, allowing for variable control of output power and improved duty-output characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the duty of PWM signal is decreased to increase output, then output power increases, but output resolution deteriorates when load impedance is low
Solution Approach 1:
The patent applies dynamics by making the rate of change of PWM duty dynamic rather than fixed. The control unit adjusts the rate of change of duty based on feedback from the output voltage, allowing the system to adapt to different load conditions. When load impedance is low, the rate of change is reduced to maintain resolution; when load impedance is high, the rate of change is increased to achieve sufficient output.
Solution Approach 2:
The patent implements feedback control by monitoring the output voltage and using it to adjust the PWM duty rate of change. The control unit receives feedback about the actual output and modifies the duty adjustment accordingly, enabling precise control of output power while maintaining resolution across varying load conditions.
2Power
If the duty of PWM signal is increased to reduce output, then output power decreases, but sufficient output cannot be secured when load impedance is high
Solution Approach 1:
The system dynamically adjusts the rate of change of PWM duty based on load conditions. When load impedance is high, the control unit increases the rate of change to ensure sufficient output power can be achieved, making the system reliable across different operating conditions.
Solution Approach 2:
The patent changes the parameter of PWM duty rate of change based on load impedance conditions. By adjusting this parameter dynamically, the system can achieve sufficient output when load impedance is high while maintaining precise control when load impedance is low.
3Device complexity
If a single transformer is used with PWM control, then device complexity is reduced, but control precision deteriorates across broad load impedance range
Solution Approach 1:
The patent maintains a simple single-transformer configuration but compensates for control precision issues by making the PWM duty adjustment dynamic. The control unit adjusts the rate of change of duty based on feedback, achieving precise control across broad load impedance ranges without increasing device complexity.
Solution Approach 2:
The system changes the PWM duty parameter dynamically based on load conditions and feedback, enabling precise output control with a single transformer. This approach maintains device simplicity while achieving the precision that would otherwise require multiple transformers or complex control circuits.
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 solution enables precise control of output when load impedance is low and achieves sufficient output when impedance is high, improving the resolution and reliability of image formation in image forming apparatuses by adjusting the rate of change of power supplied to the transformer.
Implementation Method 1
a transformer (24) having a primary coil (24a) and a secondary coil (24b)
Data Source
AI summary
A power device includes a transformer, a control signal outputting unit, and a power adjusting unit. The transformer has a primary coil and a secondary coil. The control signal outputting unit variably controls a parameter value and outputs, based on the parameter value, a control signal for controlling output power from the secondary coil. The power adjusting unit receives the control signal from the control signal outputting unit and adjusts power supplied to the primary coil based on the control signal. The power adjusting unit modifies a rate of change within a range in which the parameter value can be variably controlled, the rate of change being a rate of change in the power supplied to the primary coil with respect to the parameter value.