Multi-Drive Machine Power Allocation Under Feed Capacity Limits
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Solution Overview
Problem
Existing machines with multiple electric drives face inefficiencies in power distribution from a common feed device, leading to underutilization of available power and potential machine shutdowns due to voltage drops when total power requirements exceed the feed device's capacity.
Innovation Solution
A control method that dynamically determines a proportion factor for each drive based on its operating state, modifying current setpoints to ensure each drive receives a power that is the product of its share factor and the available total power, utilizing drive controllers with integral components to optimize power allocation and avoid reduction in power supplied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power supply unit is dimensioned to provide maximum power to all drives simultaneously, then the drives can operate at full power without voltage drops, but the power supply unit becomes bulky and expensive
Solution Approach 1:
The patent applies dynamics by making the power distribution dynamic rather than static. The control device continuously monitors the total power requirement and dynamically adjusts the power allocation to each drive based on actual needs. This allows the power supply unit to be sized for average power consumption rather than peak power, reducing its size while maintaining voltage stability through real-time adaptive control.
2Weight of stationary object
If the power supply unit is dimensioned smaller to reduce costs and size, then the power reserves remain unused for most operating time, but the unit cannot provide sufficient power when all drives require maximum power simultaneously
Solution Approach 1:
The control device dynamically adjusts power distribution based on real-time monitoring of drive power requirements. When total power requirements are low, the power supply operates at partial capacity. When all drives require maximum power simultaneously, the control device detects this condition and redistributes power dynamically, ensuring sufficient power is available to maintain productivity while the power supply unit remains compact.
3Ease of operation
If a fixed percentage of remaining power is allocated to each drive type, then the power distribution is simple to implement, but the distribution is inefficient and does not match actual drive needs
Solution Approach 1:
The control device implements feedback by continuously monitoring the actual power requirements of each drive and comparing them with the allocated power. Based on this feedback, the control device dynamically adjusts the power distribution to match actual needs, eliminating the inefficiencies of fixed percentage allocation while maintaining implementation simplicity through automated control.
4Productivity
If the control device dynamically determines proportion factors for each drive, then full utilization of available power is achieved, but the control complexity increases
Solution Approach 1:
The control device uses feedback from drive controllers to dynamically determine proportion factors. Each drive controller reports its power needs, and the control device calculates appropriate proportion factors that ensure full utilization of available power. This feedback mechanism automates the complex calculations and adjustments, achieving high power utilization efficiency without excessive control complexity.
Solution Approach 2:
The drive controllers themselves participate in the power allocation process by reporting their power requirements and receiving adjusted setpoints. This self-service approach distributes the control complexity across multiple components rather than concentrating it all in the central control device, making the system more manageable while achieving optimal power distribution.
Data Source
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AI summary
The invention relates to a control device (6) of a machine that monitors a power supply (P1*), which power supply (P1*) is drawn by drives (1a) of the machine via a feed device (2). The control device (6) switches from a normal operation to a special operation, or vice versa, as soon as the power supply (P1*) exceeds an upper switching value (GO) or falls below a lower switching value (GU). In both operating modes, the control device (6) cyclically determines preliminary current setpoint values (I1j*) for the drives (1a) in such a way that operating states of the drives (1a) are approximated to respective basic setpoint values (B1j*) as far as possible. Said control device controls the drives (1a) in both operating modes in accordance with resulting current setpoint values (I1j*). In normal operation, the resulting current setpoint values (I1j *) match the preliminary setpoint values. In special operation, the control device (6) determines a total power (P1) available to the drives (1a). Furthermore, said control device dynamically determines a respective proportional factor (fj) for the drives (1a) by evaluating current nominal and/or actual operating states of the drives (1a). The control device determines the resulting current setpoint values (I1j*) by modifying the preliminary current setpoint values (I1j *) in such a way that only one respective power is obtained by the respective drive (la), said power resulting as a product of the respective proportional factor (fj) and the available total power (PI). The control device (6) implements drive registries (10) for the first drives (1a), to which the basic setpoint values (B1j*) and the basic actual values (B1j) are fed, and by means of which the preliminary first current setpoint values (I1j*) are determined. The drive registries (10) have control characteristics having an integral part. The preliminary first current setpoint values (I1j*) enter into the determination of the proportional factors (fj).