Heat-Pump Compressor Speed Control to Reduce Resonance Vibration
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Solution Overview
Problem
Household appliances with heat-pump arrangements often experience resonances during operation, leading to negative effects such as noise and component wear, which existing technologies have not adequately addressed.
Innovation Solution
A household appliance with a heat-pump arrangement featuring a variable speed compressor and a control and drive unit that operates the compressor within specific speed ranges to minimize resonance by maintaining the speed at upper or lower limits of forbidden compressor speed ranges and reducing the time for crossing these ranges with a high speed gradient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the compressor speed is controlled to avoid the forbidden compressor speed range (FCSR), then resonance vibrations are reduced, but the time required for speed transitions increases
Solution Approach 1:
The patent applies the 'Skipping' principle by intentionally allowing the compressor speed to pass through the forbidden compressor speed range (FCSR) during transitions, rather than avoiding it. The control unit is configured to increase or decrease the compressor speed directly through the FCSR range, skipping the intermediate speeds that would cause resonance. This approach reduces the total transition time while managing resonance effects through controlled passage rather than avoidance.
2Object-affected harmful factors
If the compressor speed is kept constant to avoid frequent transitions, then resonance is minimized, but the heat pump efficiency decreases
Solution Approach 1:
The patent applies the 'Dynamics' principle by making the compressor speed variable and adaptable to different operating conditions. The control unit dynamically adjusts the compressor speed based on the current operating point, allowing the system to optimize efficiency while managing resonance. The control strategy includes detecting when the current operating point is within or near the FCSR and temporarily adjusting the speed setpoint to avoid resonance, then returning to the optimal efficiency speed when resonance conditions are no longer present.
3Reliability
If the compressor speed transitions smoothly through the FCSR, then component wear is reduced, but the period for speed change increases
Solution Approach 1:
The patent applies the 'Skipping' principle to rapidly transition through the FCSR range, minimizing the time spent at speeds that cause resonance and excessive wear. The control unit implements this by calculating the optimal transition path that passes through the FCSR as quickly as possible while still respecting compressor mechanical limits. This approach balances wear reduction with time efficiency by limiting exposure to harmful resonance conditions rather than prolonged smooth transitions.
Data Source
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AI summary
The invention relates to a household appliance having a heat-pump arrangement, in particular a domestic laundry or dishes treatment machine, more preferably a drying machine, a washer dryer (2), a washing machine or a dishwasher, wherein the household appliance comprises: a cabinet housing (4), a heat pump (34) having a variable speed compressor (46), and a control and drive unit (65, 66) configured for operating the compressor (46) at a given speed (Sg) or a given power (Pg). The control and drive unit (65, 66) is adapted to control the compressor (46) in a speed range in which at least one forbidden compressor speed range (FCSR)(72, 74) defining a compressor speed range where the compressor (46) is normally not to be operated is specified, (46) such that its speed is at least temporally kept above or at an upper limit (72a, 74a) or to be at least temporally kept below or at a lower limit (72b, 74b) of the forbidden compressor speed range and such that a period for increasing the speed from a lower limit (72b, 74b) to an upper limit (72a, 74a) or for decreasing the speed from an upper limit (72a, 74a) to a lower limit (72b, 74b) of the forbidden compressor speed range (FCSR) is reduced or minimized.