Pump Assembly Dynamic Voltage Control for Switching Loss Reduction
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Solution Overview
Problem
Speed-controlled wet rotor centrifugal pumps face high switching losses in frequency converters and inefficiencies in power consumption due to fixed input voltage settings, which are not optimized for minimal power consumption.
Innovation Solution
A pump assembly with a control unit that includes a frequency converter, voltage converter, and a controller to dynamically adjust the input voltage based on actual power consumption, using a minimum power loss algorithm to minimize switching, conversion, and motor losses, and to manage power consumption rates, thereby optimizing power usage across different operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the switching frequency of the frequency converter is increased to drive the motor with a sinusoidal pulse width modulated signal, then the motor control precision is improved, but switching losses in the frequency converter increase
Solution Approach 1:
The patent applies dynamics by making the input voltage to the frequency converter dynamically adjustable rather than fixed. The voltage converter continuously adapts the input voltage level based on operating conditions to minimize switching losses while maintaining effective motor control. This resolves the contradiction by allowing the system to operate at optimal voltage levels that reduce switching frequency requirements and associated losses.
Solution Approach 2:
The patent changes the voltage parameter (input voltage to frequency converter) as a key control variable. By adjusting the input voltage within a range between minimum and maximum values, the system can optimize the modulation index and reduce switching losses. This parameter change enables the frequency converter to achieve effective motor control with reduced switching activity, thereby lowering energy losses.
2Device complexity
If the input voltage to the frequency converter is fixed, then the device complexity is reduced, but the overall power consumption increases
Solution Approach 1:
The patent introduces dynamic voltage adjustment capability through the voltage converter, which continuously adapts the input voltage to the frequency converter based on actual power consumption and operating conditions. This dynamic approach minimizes overall power consumption by optimizing voltage levels in real-time, resolving the contradiction between fixed voltage simplicity and energy efficiency.
Solution Approach 2:
The patent implements feedback control where the controller monitors actual power consumption and uses this information to adjust the input voltage via the voltage converter. This closed-loop feedback mechanism enables the system to automatically optimize power consumption without requiring complex manual intervention, thereby achieving energy efficiency while maintaining manageable device complexity.
3Loss of energy
If the modulation index is maximized by adapting the input voltage, then switching losses in the frequency converter are minimized, but the device complexity increases
Solution Approach 1:
The patent achieves multi-functionality by integrating the voltage converter and frequency converter in a unified control system. The voltage converter serves multiple purposes: it adapts the input voltage to maximize the modulation index, minimizes switching losses, and contributes to overall power consumption optimization. This universal approach reduces the need for separate specialized components, thereby managing device complexity while achieving energy efficiency.
Solution Approach 2:
The voltage converter acts as an intermediary component between the power source and the frequency converter. It mediates the voltage adaptation process, enabling the frequency converter to operate with optimized input voltage levels that maximize the modulation index and minimize switching losses. This intermediary role simplifies the overall system architecture compared to redesigning the frequency converter itself, thereby managing device complexity.
Data Source
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AI summary
The present disclosure provides a pump assembly (1) comprising a pump unit (2), an electrical drive motor (203) for driving the pump unit (2), and a control unit (201) for controlling the drive motor (203), wherein the control unit (201) comprises a frequency converter (209), a voltage converter (207) and a controller (211), wherein the voltage converter (207) is configured to provide an input voltage (Uin) to the frequency converter (209), the input voltage (Uin) being adjustable within a voltage range between a minimum input voltage (Umin) and a maximum input voltage (Umax), wherein the controller (211) is configured to determine an actual power consumption of at least one of the drive motor (203), the frequency converter (209) and the voltage converter (207) during operation of the pump unit (2), and wherein the controller (211) is configured to tune the input voltage (Uin) depending on the determined actual power consumption during operation of the pump unit (2).