Vacuum Cleaner Motor Control via Periodic Phase Angle Alternation
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Solution Overview
Problem
Existing methods for controlling the power of vacuum cleaners using sinusoidal AC voltage and phase control result in only partial reduction of harmonics, leading to the need for limiting maximum power consumption and sometimes causing unwanted vibrations.
Innovation Solution
A method that periodically changes both the leading edge and trailing edge phase angles in full waves of the sinusoidal AC voltage, generating a control signal with a lower frequency to reduce harmonic amplitudes, particularly at critical frequencies like 150 Hz, allowing for higher power consumption without vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If phase control angle is used to control power consumption, then power adjustment is achieved, but harmonics are generated causing vibrations and requiring power limits
Solution Approach 1:
The patent applies periodic action by alternating between different phase control strategies across successive full waves of the AC voltage. Specifically, it uses phase control in one full wave and phase cut-off in the next full wave, creating a periodic pattern that reduces harmonic amplitudes at integer multiples of the mains frequency while maintaining power adjustment capability.
Solution Approach 2:
The patent segments the control approach by dividing the AC voltage waveform into individual full waves and applying different control methods to each. This segmentation allows the system to treat each half-cycle independently, alternating between phase control and phase cut-off techniques to achieve harmonic reduction while maintaining overall power control.
2Object-generated harmful factors
If maximum power consumption is limited to reduce harmonics, then harmonic limits are met, but vacuum cleaner performance is reduced
Solution Approach 1:
By implementing periodic alternation between phase control and phase cut-off methods across successive full waves, the patent achieves harmonic reduction without requiring a permanent reduction in maximum power consumption. The periodic switching allows the motor to operate at higher power levels while the alternating control strategies cancel out harmful harmonics.
3Object-generated harmful factors
If phase control angle is varied to change harmonic spectrum, then some harmonic reduction is achieved, but vibrations still occur and power must be limited
Solution Approach 1:
The patent goes beyond simple phase angle variation by implementing periodic alternation between phase control and phase cut-off methods. This periodic action creates a more effective harmonic cancellation pattern that reduces vibrations at the motor and fan, allowing full power operation without the vibrations that plague conventional phase control methods.
Data Source
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AI summary
The method involves operating a blower (16) by an electric motor (14) that is supplied with sinusoidal alternating voltage. A phase leading angle and phase trailing angle of the sinusoidal alternating voltage are periodically changed for each full wave of the sinusoidal alternating voltage. A firing angle is triggered for controlling the electric motor, and is made to correspond to the phase leading angle, where the change in the phase leading angle and phase trailing angle is determined depending on the firing angle or predetermined threshold value. An independent claim is also included for a vacuum cleaner comprising a controlling device.