DC-Link Current Sensing for Low-Complexity Motor Control
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Solution Overview
Problem
Sensorless motor driving apparatuses face challenges in efficiently controlling motor operations due to higher calculation complexity and difficulty in managing phase currents, especially when using a single shunt resistor for current detection, leading to increased manufacturing costs and operational intricacies.
Innovation Solution
A motor driving apparatus that employs a dc-link resistor element and a signal generator to process current signals, generating multiple signals for the controller to calculate phase currents and control inverter output power, reducing calculation loads and simplifying motor control through separate signal filtering and amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sensorless type motor driving apparatus uses one shunt resistor for current detection, then manufacturing cost is reduced, but calculation complexity and control difficulty increase
Solution Approach 1:
The patent introduces a signal generator as an intermediary component that processes the single shunt resistor signal and generates multiple phase current signals. This mediator handles the computational complexity, leaving the controller with simpler control tasks while maintaining cost-effectiveness through single shunt resistor usage
Solution Approach 2:
The patent replaces the need for multiple physical shunt resistors with a single shunt resistor combined with signal processing electronics. The signal generator electronically synthesizes multiple phase current signals from the single resistor measurement, substituting physical components with electronic signal manipulation
2Ease of manufacture
If a sensorless type motor driving apparatus uses one shunt resistor for current detection, then manufacturing cost is reduced, but control operation difficulty increases
Solution Approach 1:
The signal generator acts as an intermediary that translates the single shunt resistor measurement into multiple phase current signals, simplifying the controller's operation. The mediator handles the complex signal reconstruction, making the control operation easier while maintaining manufacturing cost benefits
3Measurement precision
If multiple signals are generated through calculation in the controller, then phase current detection is achieved, but controller calculation load increases
Solution Approach 1:
The patent segments the signal processing functions by introducing a dedicated signal generator component. This component handles the computationally intensive signal reconstruction tasks, while the controller focuses on motor control operations, dividing the calculation load and improving overall system efficiency
Solution Approach 2:
The signal generator serves as an intermediary that performs the complex calculation work of generating phase current signals from the single shunt resistor measurement. This mediator absorbs the computational burden, reducing the controller's calculation load while maintaining accurate phase current detection
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 allows for efficient motor control with reduced calculation complexity and manufacturing costs, enabling precise phase current calculation and power management, thereby improving the operational efficiency of sensorless motor driving systems.
Implementation Method 1
a dc-link resistor element disposed between a dc-link capacitor and an inverter, and a signal generator configured to generate a plurality of signals, on the basis of voltage on both ends of the dc-link resistor element
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A motor driving apparatus for a home appliance includes: a power supply part configured to supply DC power, a DC-Link capacitor connected to the power supply part, an inverter connected to the DC-Link capacitor and comprising a plurality of switching elements, the inverter being configured to convert, by operating the plurality of switching elements, the DC power into AC power and output the converted AC power to a motor, a DC-Link resistor element disposed between the DC-Link capacitor and the inverter, a signal generator connected to the DC-Link resistor element and configured to generate and output a plurality of signals based on an output current flowing through the DC-Link resistor element, and a controller configured to control the inverter based on the plurality of signals received from the signal generator.