System for controlling a resonant linear compressor piston, method for controlling a resonant linear compressor piston, and resonant linear compressor

Patent metadata

Field	Value
Publication number	US-9915260-B2
Application number	US-201615291613-A
Country	US
Kind code	B2
Filing date	Oct 12, 2016
Priority date	May 5, 2010
Publication date	Mar 13, 2018
Grant date	Mar 13, 2018

Abstract

A control method and a system for controlling the piston of a resonant linear compressor including at least one electronic control unit, the electronic control unit including at least one observing electronic circuit and at least one control circuit associated to each other. The observing electronic circuit is configured for: measuring at least one electric magnitude of the electric motor; estimating at least one set of electric parameters and at least one set of mechanical parameters of the resonant linear compressor; and estimating and providing at least one control parameter of the system for the control circuit based on the measured electric magnitude measured and on the estimated set of electric and mechanical parameters. The control circuit is configured for actuating the electric motor from the at least one control parameter.

First claim

The invention claimed is:

1. A control method for controlling a piston of a resonant linear compressor, the resonant linear compressor ( 100 ) comprising at least one electric motor, the electric motor being actuated by a frequency inverter, the control method comprising the following steps:
a) measuring an operation current at one operation cycle of the resonant linear compressor ( 100 );
b) calculating an operation period (T R ) of the resonant linear compressor ( 100 ) from the operation current of the electric motor measured in step a), and on the basis of the calculated operation period (T R ), calculating a resonance frequency (F R ) for the actuation of the resonant linear compressor;
c) calculating a current of the electric motor (i e (t)), a piston displacement (d e (t)) and a piston velocity (v e (t)) at each one of the operation periods (T R ) of the resonant linear compressor ( 100 ) at a discretization frequency (F d ),
d) calculating a current error (i eo ) by the difference between the operation current measured in step a) and the calculated current calculated in step c) at each one of the operation periods (T R ) of the resonant linear compressor ( 100 );
e) calculating a maximum displacement (D MAX ) of the piston ( 1 ) of the resonance linear compressor ( 100 ) from the piston displacement (d e (t)) calculated in step c);
f) calculating, from the maximum displacement (D MAX ) calculated in step e), from the piston velocity (V e (t)) calculated in step c) and from the operation current (i m ) measured in step a), a value of operation voltage (u c ) to be applied to the electric motor of the linear compressor ( 100 ); and
g) applying to the electric motor of the resonant linear compressor ( 100 ) the value of operation voltage (u c ) calculated in step k).

2. The control method for the piston of a resonant linear compressor according to claim 1 , wherein an electric mathematical model of the linear compressor ( 100 ) is defined on the basis of an electric circuit RL in series with a voltage source and equated through the following(equation:
V ENT ( t )= V R ( i e ( t ))+ V L ( i e ( t ))+ V MT ( v e ( t ))
wherein:
V R (i e (t))=R·i e (t); resistance voltage [V];

V
L

⁡

(

i
e

⁡

(
t
)

)

=

L
·

d
⁢

⁢

i
e

⁡

(
t
)

d
⁢

⁢
t

;

inductor voltate [V];
V MT (V e (t))=K MT ·v e (t); voltage induced in the motor or FCEM [V];
V ENT (t); feed voltage [V];
R; electric resistance of the compressor motor
L; inductance of the compressor motor ( 100 )
K MT ; constant of force and voltage of the motor
v e (t); calculated piston velocity
i e (t); calculated motor current.

3. The control method for the piston of a resonance linear compressor according to claim 1 , wherein the mechanical mathematical model of the linear compressor ( 100 ) is defined on the basis of a mass/spring mechanical system equated through the following equation;

m
·

d
2

⁢

d
e

⁡

(
t
)

d
⁢

⁢

t
2

=

F
MT

⁡

(

i
e

⁡

(
t
)

)

-

F
ML

⁡

(

d
e

⁡

(
t
)

)

-

F
AM

⁡

(

v
e

⁡

(
t
)

)

-

F
G

⁡

(

d
e

⁡

(
t
)

)

wherein:
F MT (i e (t))=K MT ·i e (t); motor force [N];
F ML (d e (t))=K ML ·d e (t); spring force [N];
F AM (v e (t))=K AM ·v e (t); dampening force [N];
F G (d e (t)); gas-pressure force inside the cylinder [N];
K MT ;

Assignees

• Whirlpool Sa
• Fundacao Univ Do Estado De Santa Catarina Udesc

Inventors

• Dainez Paulo Sergio
• De Oliveira Jose
• Nied Ademir

Classifications

• F04B2201/0202

  Linear speed of the piston · CPC title

• F04B35/045 Primary

  using solenoids · CPC title

• F04B2201/0206

  Length of piston stroke · CPC title

• H02K7/14

  Structural association with mechanical loads, e.g. with hand-held machine tools or fans (with fan or impeller for cooling the machine H02K9/06) · CPC title

• F04B51/00

  Testing machines, pumps, or pumping installations · CPC title