Linear compressor controller
AssigneeFisher & Paykel Appliance Limited
InventorsZhuang Tian, John H. Boyd, Jr.
Life of this patent
Estimating the term…
Abstract
A control for a linear compressor energises the linear motor in harmony with the present natural frequency of the compressor. The controller monitors the present operating frequency and compares the frequency with one or more outer limit thresholds. The control may remove power from the linear motor if the running frequency drops below a lower threshold. The control may reduce power to the linear motor if the running frequency rises above an upper threshold. The control uses compressor running frequency to operate the comperssor within safe operating limits.
Claims21
A method of controlling a free-piston linear compressor comprising the steps of:
- energizing said compressor according to a demand load so that said compressor reciprocates at its natural frequency according to the system operating conditions,
- monitoring the frequency of reciprocation of said compressor, and ceasing to energise said compressor when the frequency of reciprocation is below a floor threshold.
A method of controlling a free-piston linear compressor comprising the steps of:
- energizing said compressor according to a demand load so that said compressor reciprocates at its natural frequency according to the system operating conditions,
- monitoring the frequency of reciprocation of said compressor, and
- reducing the power applied to said compressor when the frequency of reciprocation is above a ceiling threshold.
A free piston gas compressor comprising:
- a cylinder,
- a piston,
- the piston reciprocable within the cylinder,
- a reciprocating linear electric motor coupled to the piston and having at least one excitation winding,
- a controller receiving feedback concerning the operation of the compressor, providing a drive signal for applying current to the linear motor in harmony with the instant natural frequency of the compressor,
- the controller including means for removing power from the compressor when the natural frequency of the compressor falls below a floor threshold.
A free piston gas compressor comprising:
- a cylinder,
- a piston,
- the piston reciprocable within the cylinder,
- a reciprocating linear electric motor coupled to the piston and having at least one excitation winding,
- a controller receiving feedback concerning the operation of the compressor, providing a drive signal for applying current to the linear motor in harmony with the instant natural frequency of the compressor,
- the controller including means for reducing power to the compressor when the natural frequency of the compressor rises above a ceiling threshold.
Dependencies are inferred from the claim text.