Speed Variator Loop Tuning via Load Mass Calculation
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Solution Overview
Problem
The commissioning of variable speed drives for hoisting applications, such as elevators, is often complex and time-consuming, requiring adjustments to current and speed regulation loops, which can be cumbersome and costly, especially when involving load sensors and current injection steps.
Innovation Solution
A method to calculate the proportional and integral gains of the speed regulation loop based on user-input parameters like nominal linear speed, rotational frequency, number of motor poles, and total load mass, eliminating the need for load sensors and current injection, allowing for off-line presetting of the speed regulation loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If automatic commissioning method from US5929400 is used, then commissioning is automated, but current injection into blocked rotor is required which complicates the process
Solution Approach 1:
The patent extracts and eliminates the complex current injection step from the commissioning process. Instead of injecting current into the blocked rotor, the system uses sensor data from normal operation to calculate regulation loop parameters, removing the problematic step while maintaining automation.
Solution Approach 2:
The system performs self-adjustment by automatically calculating the proportional and integral gains using data from its own sensors (current sensor 22 and speed encoder 24) during normal operation, without requiring external calibration equipment or blocked rotor conditions.
2Extent of automation
If load sensor is used to adjust speed regulation loop as in JP 08 012206, then proportional gain can be automatically adjusted, but load sensor cost and complexity increase
Solution Approach 1:
The patent uses existing sensors (current sensor 22 and speed encoder 24) as intermediaries to indirectly determine load mass. Instead of directly measuring mass with a load sensor, the system calculates mass from electrical parameters and speed data, eliminating the need for expensive direct mass measurement equipment.
Solution Approach 2:
The patent replaces the mechanical load sensor with an electrical calculation system. By substituting direct mechanical mass measurement with electrical parameter analysis (current, voltage, frequency), the system achieves the same functional result without the physical sensor.
3Manufacturing precision
If manual adjustment of regulation loops is performed, then precise tuning is possible, but commissioning time and complexity increase
Solution Approach 1:
The system performs preliminary automatic calculation of optimal proportional and integral gains using data collected during normal operation. This preliminary action eliminates the need for time-consuming manual trial-and-error tuning, providing precise parameters ready for implementation without extended commissioning time.
Solution Approach 2:
The system uses feedback from actual operational data (current measurements from sensor 22, speed measurements from encoder 24) to automatically calculate and optimize regulation loop parameters. This closed-loop approach ensures precise tuning based on real system behavior rather than theoretical estimates.
Data Source
Figure 1~2
AI summary
The invention relates to a method for setting a speed regulating loop of a speed variator intended to control a motor connected to a lifting load. The method involves a step of calculating a proportional gain (KP) and an integral gain (Ki) of the speed regulating loop, as a function of the nominal linear speed of the load, of the nominal rotational frequency of the motor, of the number of pairs of motor poles and of the total mass of the load.