Motor Control Device Power Consumption Calculation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional motor driving devices with regenerative resistance fail to accurately calculate power consumption due to incomplete accounting for power accumulated in smoothing capacitors, leading to inaccuracies in energy loss calculation.
Innovation Solution
A motor control device comprising a rectifying unit, smoothing capacitor, regenerative resistance, inverter, current detection unit, velocity calculation unit, torque calculation unit, servo control unit, and power-consumption calculation unit, which determines the energized state of the regenerative resistance to accurately calculate power consumption by considering both power loss and motor output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the conventional technique considers negative total value as zero power consumption, then the calculation is simplified, but the power consumption cannot be calculated accurately because power accumulated in smoothing capacitor is treated as loss
Solution Approach 1:
The invention changes the calculation parameter from simple total value to a conditional parameter that considers the energized state of regenerative resistance. By detecting whether regenerative resistance is energized and adjusting the power consumption calculation accordingly (using total value when energized, zero when not energized), the system achieves accurate power consumption measurement while maintaining calculation feasibility.
2Loss of energy
If regenerative power is entirely consumed by regenerative resistance, then the power loss calculation is accurate, but the reusable power accumulated in smoothing capacitor is incorrectly calculated as loss
Solution Approach 1:
The invention introduces feedback by detecting the energized state of regenerative resistance and using this information to adjust the power consumption calculation. The system continuously monitors whether regenerative resistance is energized and feeds this information back to the power consumption calculation unit, enabling it to distinguish between power actually consumed as loss and power accumulated in the smoothing capacitor for reuse.
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
Enables accurate power calculation without the need for dedicated measurement devices, ensuring precise identification of electricity costs and optimal power facility selection.
Implementation Method 1
a rectifying unit that converts power from an AC power supply to DC power
Implementation Method 2
a smoothing capacitor for main-circuit smoothing that is connected to an output of the rectifying unit
Implementation Method 3
a regenerative resistance, one terminal of which is connected to one of electrodes of the smoothing capacitor, and which consumes regenerative power
Implementation Method 4
an inverter unit that converts DC power output from the rectifying unit to AC power suitable for driving a motor
Data Source
AI summary
A motor control device includes a power-consumption calculator that calculates a power loss L according to a motor current I or according to the motor current I and a motor velocity v, and calculates a motor output W from a product of the motor velocity v and a torque τ or thrust force, to determine whether a regenerative resistance is in an energized state. When the regenerative resistance is in an energized state, if a total value W+L of the power loss L and the motor output W is equal to or greater than 0 (W+L≧0), the power-consumption calculator calculates a power consumption P as W+L, and if a total value W+L of the power loss L and the motor output W is less than 0 (W+L<0), the power-consumption calculator calculates the power consumption P=0.