Method for simultaneously actuating a three-phase motor in a two-phase operation and a single-phase motor, motor controller and electric household appliance
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Solution Overview
Problem
Existing technologies face challenges in simultaneously controlling a three-stranded engine in a two-phase operation and a striking engine of an electrical household appliance using a three-phase converter, while minimizing coupling between the two engines.
Innovation Solution
The procedure involves using a three-phase converter to control the three-stranded engine with the first and second phases, and the striking engine with the second and third phases, while employing PWM signals to control half-bridges with high-side and low-side transistors. This approach reduces mutual influence by switching off the appropriate transistors during PWM signal periods, thereby minimizing voltage errors and coupling between the engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a three-phase converter is used to simultaneously control a three-phase motor in two-phase operation and a single-phase motor, then both motors can be operated from a single converter, but voltage errors and coupling between the motors occur due to current-dependent voltage drops in the converter
Solution Approach 1:
The patent segments the control of the two motors by assigning them to different phase combinations of the three-phase converter. The three-phase motor uses phases U and V, while the single-phase motor uses phases V and W. This segmentation allows independent control of each motor through dedicated PWM channels, reducing the coupling effect caused by shared phase currents.
Solution Approach 2:
The control device preliminarily determines the current direction in the shared phase V before switching operations. Based on this preliminary determination, it pre-configures which transistors to switch on or off to minimize voltage errors. This preliminary action prevents the accumulation of voltage errors that would occur if switching decisions were made without considering current direction.
2Ease of operation
If standard PWM control is used without considering current direction, then control implementation is simple, but voltage errors accumulate and coupling between motors increases
Solution Approach 1:
The control device implements feedback by continuously monitoring the current direction in phase V and using this information to adjust transistor switching decisions. The control device determines whether current flows from the converter to the motors or from the motors to the converter, and based on this feedback, it selects the appropriate switching strategy to minimize voltage errors while maintaining operational simplicity.
3Reliability
If additional hardware is added to eliminate coupling between motors, then voltage errors can be reduced, but system complexity and cost increase
Solution Approach 1:
The system uses its existing resources - the three-phase converter's transistors and the control device's processing capability - to eliminate voltage errors and coupling. By intelligently controlling the switching of existing transistors based on current direction, the system achieves error reduction without requiring additional hardware components, making the solution cost-neutral while improving reliability.
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 solution effectively reduces voltage errors and coupling between the three-stranded and striking engines, eliminating the need for additional hardware and minimizing computing power requirements, thus enabling cost-neutral implementation.
Implementation Method 1
The converter comprises three half-bridges with high-side transistors and low-side transistors. These half-bridges are controlled with PWM (pulse width modulation) signals.
Data Source
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AI summary
The invention relates to a method for simultaneously controlling a three-phase motor (M1) in two-phase operation and a single-phase motor (M2, M3) of an electrical household appliance by means of a three-phase (U, V, W) inverter, such that the three-phase motor (M1) is energized by means of a first phase (U) and a second phase (V) of the three-phase (U, V, W) inverter, and the single-phase motor (M2, M3) is energized by means of the second phase (V) and a third phase (W) of the three-phase (U, V, W) inverter, wherein the inverter has several half-bridges with high-side transistors (T1, T3, T5) and low-side transistors (T2, T4, T6), wherein each of the motors (M1, M2, M3) has a half-bridge with a high-side transistor (T1, T3, T5) and a low-side transistors (T2, T4, T6) are assigned, which are controlled with PWM signals, the method having the following characteristics when several of the motors (M1, M2, M3) are operated in parallel: a) switching,Depending on the direction of the current flowing, either the associated high-side transistor (T1, T3, T5) or the associated low-side transistor (T2, T4, T6) is switched on, and the other associated low-side transistor (T2, T4, T6) or high-side transistor (T1, T3, T5) is left off during one or more duty cycles of the PWM signal. The invention further relates to a motor controller comprising the inverter configured to control the three-phase motor (M1) in two-phase operation and the single-phase motor (M2, M3) of an electrical household appliance according to the method, as well as an electrical household appliance comprising the motor controller.