Voltage Doubler Control for Faster Motor Acceleration
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Solution Overview
Problem
Existing power conversion devices for motor speed control face challenges in accelerating motors quickly enough to reduce tact time in metal processing machines, as the method of boosting DC voltage after receiving a motor acceleration command results in longer transient times, making it difficult to achieve high-acceleration operations.
Innovation Solution
A power conversion device with a voltage doubler circuit that is activated earlier than the motor speed command rise, allowing for earlier boosting of DC voltage, thereby shortening the motor acceleration time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the voltage doubler circuit is activated after receiving the motor acceleration command, then the DC voltage can be boosted to enable high-speed motor operation, but the transient time for voltage boosting increases the motor acceleration time
Solution Approach 1:
The voltage doubler circuit is activated in advance before the motor acceleration command is issued. The controller detects the acceleration command and activates the voltage doubler circuit a predetermined period beforehand, allowing the DC voltage to be boosted before the motor needs to accelerate, thus eliminating the delay between voltage boosting and motor acceleration
Solution Approach 2:
The invention anticipates the need for high voltage by activating the voltage doubler circuit before the acceleration command is given. This preliminary action counteracts the potential delay by ensuring the voltage is already boosted when the motor acceleration begins, preventing the transient time from adding to the overall acceleration time
2Productivity
If the voltage doubler circuit is activated earlier to shorten acceleration time, then the motor can accelerate faster, but the power capacity of the voltage doubler circuit may need to be increased
Solution Approach 1:
The voltage doubler circuit is activated for a predetermined period before the acceleration command, which is more than the minimum necessary time. This excessive advance activation ensures that the voltage boosting is complete before acceleration begins, allowing the use of a smaller voltage doubler circuit with lower power capacity while still achieving the desired acceleration performance
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
This approach reduces the time required for motor acceleration, thereby decreasing the tact time of metal processing devices without increasing the power capacity of the voltage doubler circuit, allowing for a more efficient and faster motor operation.
Implementation Method 1
a voltage doubler circuit capable of switching between a full-wave rectification mode and a voltage doubler rectification mode depending on a load state of a motor
Implementation Method 2
The DC voltage from the voltage doubler circuit becomes a full-wave rectified voltage (once) in the full-wave rectification mode, and becomes a double voltage (twice) in the voltage doubler rectification mode
Data Source
AI summary
A power conversion device capable of shortening the time required for acceleration of a motor and a metal processing device including the power conversion device are provided. Then, a power conversion device 10 includes a converter 100 configured to convert an AC voltage from outside to a DC voltage Vo and a converter controller 107 configured to control the converter 100. The converter 100 includes a voltage doubler circuit 104 configured to boost the DC voltage Vo when activated, and outputs the DC voltage Vo having a voltage value different in accordance with the activation and stop of the voltage doubler circuit 104. The converter controller 107 activates the voltage doubler circuit 104 at a first time that is earlier by a predetermined period than a second time at which a speed command value ω* of the motor 130 rises from a predetermined value.