Single-Shunt Signal Generation for Sensorless Motor Current 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, which increases manufacturing costs and complicates motor control.
Innovation Solution
A motor driving apparatus that processes currents through one shunt resistor using various circuit components to generate multiple signals, allowing a controller to reduce calculation loads and efficiently control inverter output power based on these signals, including signal amplification and filtering to improve noise reduction and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sensorless type motor driving apparatus is used to reduce manufacturing cost, then manufacturing cost is reduced, but calculation amount of controller increases and control complexity increases
Solution Approach 1:
The patent introduces a signal generator as an intermediary component between the shunt resistor and the controller. This signal generator hardware-wise processes the current signal through circuit components (amplifiers, filters) to generate multiple processed signals, thereby reducing the calculation burden on the controller while maintaining sensorless operation benefits
2Device complexity
If one shunt resistor is used for current detection to reduce component quantity, then device complexity is reduced, but calculation amount of controller increases
Solution Approach 1:
The signal generator acts as an intermediary that hardware-processes the single shunt resistor output through multiple circuit paths (different amplifiers and filters), generating multiple processed signals that reduce the computational burden on the controller while maintaining the simplicity of using only one shunt resistor
3Productivity
If multiple signals are generated through hardware processing to reduce controller calculation, then controller processing load is reduced, but device complexity increases
Solution Approach 1:
The signal generator performs multiple functions using a relatively compact circuit structure: it amplifies signals through multiple amplifiers, filters different frequency components through parallel filter paths, and generates multiple processed signals simultaneously. This multi-functionality reduces controller load while keeping the added complexity manageable
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 reduces the calculation burden on the controller, enhances motor control efficiency, and lowers manufacturing costs by simplifying the control of motor operations using a single shunt resistor, while maintaining precise control over phase currents and rotation speed.
Implementation Method 1
a first filter having a first bandwidth, eliminating noise included in output of the signal amplification part, and then outputting the first signal
Implementation Method 2
a second filter having a second bandwidth, eliminating noise included in output of the signal amplification part, and then outputting the second signal
Data Source
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.