Control circuit applied to lifting platform and method of controlling the same
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Solution Overview
Problem
Traditional electric lifting tables experience a decrease in output power when loads increase, leading to poor load capacity and inability to lift heavy loads, requiring costly upgrades to the converter, resulting in a bulky circuit.
Innovation Solution
A control circuit comprising a conversion circuit and a control unit that adjusts the PWM signal based on detection signals from the AC/DC conversion circuit, decreasing the motor's rotation speed when output power falls below a threshold to maintain stable DC voltage and power, allowing the lifting platform to operate efficiently under heavy loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the converter output power is increased to drive heavier loads, then the load capacity is improved, but the cost and circuit size increase
Solution Approach 1:
The patent applies dynamic control by adjusting the duty cycle of PWM signals based on real-time detection of DC voltage levels. The control unit dynamically modifies the switching characteristics of the DC/DC conversion circuit to optimize power delivery under varying load conditions, allowing the system to adapt its power output without requiring a larger converter design
Solution Approach 2:
The system changes operational parameters (duty cycle ratio) based on detected voltage conditions. When DC voltage drops below a threshold indicating heavy load, the control unit adjusts the duty cycle to maintain optimal power transfer, effectively changing the electrical parameters to match load requirements without hardware changes
2Power
If the converter output power is increased to drive heavier loads, then the load capacity is improved, but the cost increases
Solution Approach 1:
The control system performs self-adjustment by detecting DC voltage levels and automatically modifying PWM duty cycles. This self-regulating mechanism allows the existing converter to serve multiple power levels without requiring external intervention or larger capacity components, reducing manufacturing costs
Solution Approach 2:
By changing the duty cycle parameter dynamically, the system achieves variable power output from a fixed-size converter. This parameter-based control eliminates the need for costly oversized converters, allowing cost-effective heavy load handling through software/control circuit adjustments rather than hardware upgrades
3Reliability
If the duty cycle is decreased to maintain DC voltage under heavy load, then the load capacity is maintained, but the motor rotation speed decreases
Solution Approach 1:
The system employs feedback control by continuously detecting DC voltage at the output of the AC/DC conversion circuit and using this information to adjust PWM duty cycle. This closed-loop feedback ensures that when voltage drops indicate heavy load conditions, the duty cycle is reduced to maintain stable voltage and prevent system failure, balancing reliability with speed control
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 maintains load capacity and enables faster lifting speeds under heavy load conditions compared to traditional methods, preventing the platform from becoming stuck due to low DC voltage or power, while avoiding the need for costly converter upgrades.
Implementation Method 1
The AC/DC conversion circuit converts the input voltage into a DC voltage
Implementation Method 2
The DC/DC conversion circuit converts the DC voltage into the output voltage
Implementation Method 3
provides an output voltage to control the motor
Data Source
AI summary
A control circuit applied to a lifting platform controls a motor to adjust the height of a platform. The control circuit includes an AC/DC conversion circuit, a DC/DC conversion circuit, a detection unit, and a control unit. The detection unit detects an output end of the AC/DC conversion circuit and provides a detection signal. The control unit provides a PWM signal according to the detection signal to control the DC/DC conversion circuit so that the DC/DC conversion circuit converts a DC voltage to an output voltage. When the control unit realizes that the DC voltage or a DC power provided by the AC/DC conversion circuit is less than a power supply threshold according to the detection signal, the control unit decreases a duty cycle of the PWM signal to maintain the DC voltage or the DC power to be greater than or equal to the power supply threshold.