JP5018357B2 - Linear compression apparatus and control method thereof - Google Patents

Description

  The present invention relates to a linear compressor driven by a linear motor used for gas compression, vapor compression or a refrigerator, and a control method thereof, and more specifically, a linear compression device for controlling the position of a piston and a control method thereof. The present invention relates to a method for controlling a linear compression apparatus that measures the inductance and back electromotive force coefficient of a coil of a linear motor.

The inductance used in the control method of the prior art is measured by measuring and recording the impedance Z and the phase angle θ while sweeping the frequency in the LCR circuit, and the phase angle θ measured in the measurement step a predetermined number of times before. A first comparison step for determining whether the phase angle is approaching a predetermined value or moving away from a value, and measuring the number of increases / decreases in θ and comparing it with a predetermined value to determine the completion of measurement. A second comparison step, and an arithmetic processing step for calculating an approximate value by performing a numerical operation on the measured values of impedance Z and phase angle θ measured and recorded in the measurement step. The second comparison step and the measurement step Is compared with a predetermined value, and if it is equal to the predetermined value, in the arithmetic processing step, the measurement frequency measured and recorded in the measurement step, the numerical calculation of the impedance Z and the phase angle θ are performed, and the inductance L ′ Seeking an approximate value. In this case, when the frequency f is set to 0 or a sufficiently low value, the impedance Z and the phase angle θ are numerically calculated using the equations (1) and (2) to obtain an approximate value of the inductance L ′ (for example, patent document) 1).

In Equation 1, ω is an angular velocity, and ω = 2πf when the circumferential ratio is π (≈3.14).

Further, an alternating current comprising an inverter composed of power semiconductor elements for converting the direct current voltage V _dc into alternating current and supplying the alternating current to the alternating current motor, and a control device for controlling the magnitude and frequency of the output voltage of the inverter. In a constant measuring method for an AC motor in a motor control device, a single-phase AC excitation signal is output based on the primary frequency command value ω ₁ and the primary voltage command value V _C1 of the inverter, and the inverter is operated by this signal. The AC motor is single-phase AC excited, the effective power current Iq and the reactive power current Id of the motor are calculated from the phase obtained by integrating the primary frequency command and the current detection value of the AC motor, and the following formula V _C1 · Iq , the following equation primary and secondary combined resistance of ^(Iq 2 + Id ²⁾ from the ratio of the AC motor _(r 1 + _{r 2)} is calculated measured, and the following equation _V C1 · Id, the following formula omega (I From the ratio of the ² + Iq ^2), calculates measured AC motor primary and secondary synthetic leakage inductance _(L 1 + L _2). That is, the combined leakage inductance (L ₁ + L ₂ ) is obtained by Equation 3 (for example, Patent Document 2).

Further, in the conventional linear compressor with piston position control, the voltage and current of the linear motor that reciprocates the piston are continuously detected, and the detected voltage V and current I are measured in advance and the coil electrical current measured in advance. From the resistor R, the piston speed is calculated using an equation including the linear motor inductance L and the counter electromotive force coefficient C, that is, the speed v = {(1 / C) (VL (dl / dt) -IR)}. Differentiating this speed, the piston acceleration is integrated to calculate the displacement, and using these quantities, the top dead center position of the piston is calculated, and the piston position is controlled without using the displacement sensor. (For example, patent document 3).
Japanese Patent No. 2751285 Patent No. 3284602 Japanese Patent No. 3413658

  However, in the inductance measurement method of Patent Document 1, the influence of the counter electromotive force generated by the speed of the mover or the rotor in a magnetic circuit such as a linear motor is not included in the equations 1 and 2, so There is a problem that the inductance and back electromotive force coefficient corresponding to the actual machine operating state cannot be measured.

  Further, in the method of measuring the combined leakage inductance of Patent Document 2, the influence of the counter electromotive force generated by the speed of the rotor (movable element) of the AC motor is not included in Equation 3 even in the magnetic circuit of the AC motor. There is a problem that the inductance and the back electromotive force coefficient corresponding to the actual operation state of the linear motor cannot be measured.

  Further, in Patent Document 3, it is necessary to continuously detect the voltage and current of the linear motor, and to perform successive differentiation processing and integration processing. In this differentiation process, the speed change is divided by a small amount of time to obtain the acceleration. If the speed change includes electrical noise, the influence of this noise will cause the acceleration to be inaccurate and correct piston displacement will not be calculated. There is a problem that the piston position is not controlled correctly. In addition, in order to perform successive differentiation and integration processing, it is necessary to provide the controller with a differentiator and an integrator. If the differentiator and the integrator are realized with an analog circuit, the circuit configuration becomes complicated, which is realized with a digital circuit. This increases the burden on the processor that performs the arithmetic processing and increases the cost.

  The present invention has been made in view of the above problems, and does not require a piston position detector, reduces the burden on a processor that performs arithmetic processing, is hardly affected by electrical noise, and can perform highly accurate piston position control. An object of the present invention is to provide a low-cost linear compressor and a control method therefor.

In order to solve the above-mentioned problem, the invention described in claim 1 includes a linear motor having a movable body having a piston disposed on a mover and a coil, and a cylinder portion in which the piston reciprocates to compress gas. A control method of a linear compression apparatus comprising: a linear compressor provided; and a power supply unit that supplies electric power to a coil of the linear motor and reciprocates a movable body of the linear compressor in a sine wave or sine wave shape,
A basic waveform generating step of generating the basic waveform by a basic waveform generating means for generating a sine wave or a sine wave basic waveform to be sent to the power supply unit;
By means of voltage measurement calculation means for measuring and calculating the voltage of the power, 2π (360 °) which is an integral multiple of three or more different voltage phase angles within one period of the frequency of the basic waveform with reference to a common timing. When the DC component of the voltage is small relative to the amplitude with the added phase angle, 2π which is an integer multiple is added to two or more different voltage phase angles within one period of the frequency with reference to the common timing. A voltage measurement calculation step for measuring the voltage at a phase angle and calculating a voltage amplitude and a voltage phase angle of a voltage waveform from the measured voltage value;
From the current measurement calculation means for measuring and calculating the current of the electric power, with a phase angle obtained by adding 2π of an integer multiple to three or more different current phase angles within one period of the frequency based on the common timing, Alternatively, when the direct current component of the current is small with respect to the amplitude, the current is set at a phase angle obtained by adding 2π which is an integral multiple of two or more different current phase angles within one period of the frequency with reference to the common timing. A current measurement calculation step for measuring and calculating the current amplitude and current phase angle of the current waveform from the measured current value;
A phase angle obtained by adding an integral multiple of 2π to three or more different displacement phase angles within one period of the frequency with reference to the common timing by a displacement measurement calculation means for measuring and calculating the displacement of the piston; or When the DC component of the displacement is smaller than the amplitude, the displacement is measured at a phase angle obtained by adding 2π which is an integral multiple of two or more different displacement phase angles within one period of the frequency with reference to the common timing. A displacement measurement calculation step for calculating a displacement amplitude and a displacement phase angle of the displacement waveform from the measured displacement value;
By means of coil calculation means for calculating based on the calculation results obtained from the measured values of the voltage, the current and the displacement, the voltage amplitude, the voltage phase angle, the current amplitude, the current phase angle, and the displacement amplitude, From the displacement phase angle, the inductance of the coil and a coil calculation step of calculating a counter electromotive force coefficient of the coil, and obtaining the inductance and the counter electromotive force coefficient in advance,
A control unit that controls the voltage or current of the power of the power supply unit;
During operation of the linear compression device, the control unit generates a sine wave or a sine wave basic waveform to be sent to the power supply unit, and within one cycle of the frequency of the basic waveform based on a common timing. The phase angle is obtained by adding an integer multiple of 2π to three or more different voltage phase angles, or within one period of the frequency of the basic waveform with reference to the common timing when the DC component of the voltage is small relative to the amplitude. Voltage measurement calculation means for measuring a voltage flowing through the coil at a phase angle obtained by adding 2π which is an integer multiple to two or more different voltage phase angles, and calculating a voltage amplitude and a voltage phase angle of a voltage waveform from the measured voltage values When,
With the phase angle obtained by adding an integer multiple of 2π to three or more different current phase angles within one period of the frequency with reference to the common timing, or when the DC component of the current is small relative to the amplitude, the common timing The current flowing through the coil is measured at a phase angle obtained by adding an integer multiple of 2π to two or more different current phase angles within one period of the frequency, and the current amplitude of the current waveform is calculated from the measured current value. Current measurement calculation means for calculating a current phase angle;
A displacement waveform computing means for computing a displacement waveform of the movable body from the voltage waveform obtained by the voltage measurement computing means and the current waveform obtained by the current measurement computing means;
Comparing the basic waveform and the displacement waveform obtained by the displacement waveform calculating means, the basic waveform correcting means for transmitting the operation signal corrected the basic waveform to the power supply unit,
It is a control method for a linear compression device, wherein the displacement waveform is calculated by the displacement waveform calculation means based on the inductance obtained in the coil calculation step and the counter electromotive force coefficient, and the position of the movable body is controlled. .

  In the first aspect of the present invention, a sine wave having a predetermined amplitude or a sine wave-like basic waveform is generated at a predetermined frequency in the basic waveform generation step, and the linear compressor of the linear compressor is generated by the power supply unit based on the basic waveform. The voltage and current of the electric power supplied to the motor are supplied to the linear motor in a state close to the actual machine operating state, and the movable body is reciprocated in a sine wave or sine wave (substantially sine wave). Next, in the voltage measurement calculation step, current measurement calculation step, and displacement measurement calculation step, the voltage, current, and displacement are measured based on the common timing, respectively, and the voltage amplitude and voltage phase angle, and the current amplitude and current are measured from the measured values. Since the phase angle, displacement amplitude and displacement phase angle are calculated, and the inductance and counter electromotive force coefficient are calculated from the calculated values in the coil calculation step, the inductance value and counter electromotive force of the linear motor coil in a state close to the actual machine operating state It is possible to determine the value of the coefficient, and since there is no need to differentiate the measured current of the prior art, the position detector is not used, it is difficult to be affected by electrical noise, the burden on the processor that performs arithmetic processing is small, It is possible to provide a control method for a linear compression apparatus that can perform position control with high accuracy.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a block diagram of a circuit relating to a control method of a linear compression apparatus according to the present invention. The configuration of the control circuit will be described with reference to FIG. The linear motor control circuit 1 a of the linear compressor 1 includes a linear compressor 2, a power supply unit 3, and a control unit 4. The linear compressor 2 includes a linear motor 50 having coils 53a, 53b, and 53c as described later (FIG. 6). A piston 58 is connected to the mover 55 of the linear motor 50 via a rod 59 to form a movable body 60. The movable body 60 is elastically supported by coil springs 71 and 72 at both ends, and has a resonance point. Is formed. It is preferable to operate the linear motor 50 at a frequency near the resonance point by operating the linear motor 50 at a frequency near the resonance point so that the gas or steam is efficiently compressed by the piston 58.

The measurement calculation step of the control unit 4 includes a basic waveform generation step 5 s by the basic waveform generation means 5, a voltage measurement calculation step 6 s by the voltage measurement calculation means 6, a current measurement calculation step 7 s by the current measurement calculation means 7, and a displacement measurement calculation means 8. Displacement measurement calculation step 8s by the coil calculation step 9 and coil calculation step 9s by the coil calculation means 9. First, in the basic waveform generation step 5s, a time signal serving as a reference is generated at a very short fixed time interval by the clock signal generation means 5b in order to set a timing reference for various processes performed by the control unit 4. Next, the frequency and amplitude of the basic waveform are set to desired values by the displacement waveform information setting means 5c. Based on this waveform information and time signal, the reference waveform generating source 5a is a sine wave or a substantially sine wave (hereinafter referred to as a sine wave). The basic waveform u (t) and timing signals for various processes performed by the control unit 4 are generated and output. Further, a predetermined direct current component U _D can be superimposed on the amplitude component U _O in the basic waveform u (t) as necessary.

  The power supply unit 3 determines the voltage and current of power supplied to the coils 53a, 53b, and 53c of the linear motor 50 based on the sine wave or sine wave basic waveform sent from the control unit 4, and the power to the coils 53a, 53b, and 53c. Supply. With this supplied power, the mover 55 of the linear motor 50 is integrated with the piston 58 and reciprocates in a sine wave or sine wave shape.

  The output of each measured value measured in the voltage measurement calculation step 6s, the current measurement calculation step 7s, and the displacement measurement calculation step 8s described below is the output of the reference waveform generation source 5a described above for each step 6s, 7s, 8s. Processing is performed based on the common timing based on the timing signal.

In the voltage measurement calculation step 6s, the voltage measurement means 6a measures the voltages at both ends of the coils 53a, 53b and 53c, and then measures each voltage value measured based on a measurement timing command described later from the voltage measurement timing means 6d. Is output from the voltage value output means 6b, and the voltage amplitude V _O of each voltage at both ends of the coils 53a, 53b, 53c from the voltage values output from the voltage amplitude voltage phase detection means 6c and the voltage based on the common timing calculated based on the arithmetic expression will be described later phase angle theta _V, is transmitted to the coil calculating means 9.

In the current measurement calculation step 7s, each current flowing through the coils 53a, 53b, 53c is measured by the current measurement means 7a, and each current value measured based on the measurement timing command from the current measurement timing means 7d is converted into a current value. The current amplitude IO of each current flowing through the coils 53a, 53b, 53c from the current value output by the output means 7b and output from the current amplitude current phase detection means 7c, and the current phase angle θI based on the common timing are described later. Is calculated based on the arithmetic expression to be transmitted to the coil calculation means 9.

In the displacement measurement calculation step 8s, the displacement measuring means 8a measures the displacement of the movable body 60 (FIG. 6) (same as the displacement of the piston 58 and the movable element 55), and then at a predetermined timing from the displacement measurement timing means 8d. each displacement value measured on the basis of a command outputted by the displacement value output means 8b, a displacement amplitude X _O of the movable body 60 from the respective displacement values output by displacement amplitude displacement phase detecting means 8c, relative to the common timing the displacement phase angle theta _X calculated based on the arithmetic expression will be described later, is transmitted to the coil calculating means 9.

The coil calculation step 9s includes a voltage amplitude V _O and a voltage phase angle θ _V calculated by the voltage amplitude voltage phase detection means 6c, and a current amplitude I _O and a current phase angle θ _I calculated by the current amplitude current phase detection means 7c. From the displacement amplitude X _O and displacement phase angle θ _X calculated by the displacement amplitude displacement phase detection means 8c, the inductances L and the counter electromotive force coefficients C of the coils 53a, 53b, 53c are calculated based on the calculation formula described later. A series of processes of the control method for calculating and calculating the inductance and back electromotive force coefficient of the linear motor is completed.

The common timing may be the basic waveform or the clock signal of the time signal generation means 5b, or any one of the measurement timings of the measurement calculation means 6a, 7a, 8a may be the common timing. it may be. Further, the voltage amplitude voltage phase detection means 6c, current amplitude current phase detection means 7c, displacement amplitude displacement phase detection means 8c add an integer multiple of 2π to the same phase angle of many cycles in addition to the arithmetic function described later. A processing function is provided for averaging the measured values measured at different phase angles.

  Next, the operation of the control method of the linear compression apparatus 1 for obtaining the inductance and the counter electromotive force coefficient of the linear motor will be described with reference to the coil 53a. The action of the coils 53b and 53c is the same as that of the coil 53a.

(Control method when there is DC component)
FIG. 2 shows voltage amplitude and voltage derived from coil voltage measurement values measured at phase angles corresponding to three or more different measurement timings of the coil voltage waveform v (t) within one cycle with reference to the common timing. The voltage vector diagram explaining the computing equation of a phase is shown.

  The case where the DC component is present means that at least one of the DC component of voltage and current of the coil 53a and the DC component of displacement of the movable body has a DC component.

(Basic waveform generation step)
In the basic waveform generation step 5s, the basic waveform generation means 5 generates a basic waveform u (t) in which a direct current component is superimposed on a sine wave of a predetermined frequency or a sine wave (substantially sine wave). For example, the basic waveform u (t) is preferably expressed by Equation 4, but the operation described below can also be applied to a sine wave (substantially sine wave).

The number 4, t is time, basic in U _O amplitude of the fundamental wave, U _D is the DC component of the basic waveform, omega is angular velocity, [pi is pi, f is a predetermined frequency, u (t) is the time t It is a waveform. The predetermined frequency is preferably a frequency in the vicinity of the resonance frequency of the vibration system formed by a synthetic spring obtained by synthesizing the movable body 60, coil springs 71 and 72, which will be described later, a gas spring, and a magnetic spring.

(Voltage measurement calculation step)
The voltage waveform v (t) measured at both ends of the coil 53a is expressed by Equation 5 because the basic waveform expressed by Equation 4 is a sine wave. In the voltage measurement calculation step 6s, with reference to the common timing from the voltage measurement timing means 6d, voltage values measured at three or more different measurement timings, that is, at three or more different phase angles within one period of the frequency of the basic waveform. To obtain the voltage amplitude V _O and the voltage phase θ _V shown in equation (5).

In Equation 5, V _O is the voltage amplitude, θ _V is the voltage phase angle based on the common timing, and V _D is the direct current component (FIG. 2).

A first phase angle (θ _V1 + θ _V ), a second phase angle (θ _V2 + θ _V ), and a third phase angle corresponding to three different measurement timings within one cycle with reference to the common timing If the voltages measured at θ _V are V ₁ , V ₂ , and V ₃ , respectively, the first voltage phase angle (θ _V1 + θ _V ), the second voltage phase angle (θ _V2 + θ _V ), and the third voltage Even if the phase angle θV is a phase angle obtained by multiplying 2π (360 °) by an integer, the values of the measured values V ₁ , V ₂ , and V ₃ do not change, so that three or more different measurement timings are within one cycle. The measurement may be performed at a timing obtained by adding an integer multiple period to three or more different measurement timings within one period. That is, when P _V , Q _V , and R _V are integers, a first voltage phase angle {(θ _V1 + θ _V ) + P _{V obtained} by adding an integer multiple of 2π to a phase angle corresponding to three or more different measurement timings. (2π)}, second voltage phase angle {(θ _V2 + θ _V ) + Q _V (2π)}, and each voltage value V measured at the third voltage phase angle {θ _V + R _V (2π)}. _{1, V} 2, _{V 3} is Ru indicated by the number 5 in 6. Accordingly, by solving the ternary simultaneous equations of Equation 6, the unknown voltage amplitude V _O , voltage phase angle θ _V , and DC component V _D are shown in Equation 7, and the voltage amplitude V _O , voltage phase angle theta _V, can be determined DC component _{V D.}

(Current measurement calculation step)
The current measurement calculation step 7s is based on the common timing from the current measurement timing means 7d, and current values measured at three or more different measurement timings within one period of the frequency of the basic waveform, that is, at three or more different phase angles. To obtain the current amplitude I _O and the current phase θ _{I shown} in Eq.

In Equation 8, I _O is the current amplitude, θ _I is the current phase angle based on the common timing, and _ID is the direct current component.

Similar to the voltage measurement calculation step 6s, the first current phase angle {θ _I1 + θ _I + P _{I) obtained} by adding an integer multiple of 2π to the phase angle corresponding to three different measurement timings in one cycle with reference to the common timing. (2π)}, the second current phase angle {θ _I2 + θ _I + Q _I (2π)}, and the third current phase angle {θ _I + R _I (2π)} are respectively measured as I ₁ , Assuming I ₂ and I ₃ , I ₁ , I ₂ , and I ₃ are expressed by Eq. 9 using Eq. 8, and Eq. 10 is obtained by solving the ternary simultaneous equations of Eq. 9, and the current amplitude I is determined from the current constant value. _{O 1} , current phase angle θ _I , and direct current component _ID can be obtained from Equation 10. Here, the _{P I,} and _{Q I,} the _{R I} is an integer.

(Displacement measurement calculation step)
The displacement measurement calculation step 8s is based on the common timing from the displacement measurement timing means 8d as a reference, and the displacement values measured at three or more different measurement timings, that is, at three or more different phase angles, within one period of the frequency of the basic waveform. The displacement amplitude X _O and the displacement phase θ _X shown in Equation 11 are obtained.

In Equation 11, X _O is the displacement amplitude, θ _X is the current phase angle based on the common timing, and X _D is the direct current component. Similar to the voltage measurement calculation step 6s, a first displacement phase angle {θ _X1 + θ _X + P () obtained by adding an integer multiple of 2π to a phase angle corresponding to three different measurement timings in one cycle with the common timing as a reference. 2π)}, the second displacement phase angle {θ _X2 + θ _X + Q (2π)}, and the third displacement phase angle {θ _X + R (2π)}, X ₁ and X ₂ , respectively. , X ₃ , X ₁ , X ₂ , X ₃ are expressed by Equation 12 using Equation 11, and Equation 13 is obtained by solving the ternary simultaneous equations of Equation 12, and the displacement amplitude X _O , The displacement phase angle θ _X and the direct current component X _D can be obtained from Equation 13. Here, P _X , Q _X , and R _X are integers.

The measurement timing of each of the above-described measurement calculation steps 6s, 7s, and 8s must be based on a common common timing, but may be the same as or different from each other in each step 6s, 7s, and 8s. Further, the measured values of voltage, current, and displacement are obtained by substituting the measured values obtained by shifting the phase angle by a small amount into Equations (7), (10), and (13), and the amplitudes V _O and I of the displacement. _{O, X O,} the phase angle _{θ V, θ I, θ X} , the DC component _{V D, I D, X D} , is the difference for the case where the phase angle does not deviate is microcrystalline small amounts, measurements of voltage , it may be used measurements of where the phase angle is shifted by a small amount. Further, when θ _V1 = θ _I1 = θ _X1 = π and θ _V2 = θ _I2 = θ _X2 = π / 2, Equations 7, 10, and 13 become simple equations.

(Coil calculation step)
The coil calculation step 9s includes a voltage amplitude V _O and a voltage phase angle θ _V of the voltage measurement calculation step 6s, a current amplitude I _O and a current phase angle θ _{I of} the current measurement calculation step 7s, and a displacement amplitude X _O of the displacement measurement calculation step 8s. determining the inductance L and the back electromotive force coefficient C of the coil 53a from each of the calculated values of the displacement phase angle theta _X and.

Calculation formulas for the inductance L and the counter electromotive force coefficient C are introduced as follows. That is, since the inductance and the counter electromotive force coefficient are coefficients generated by the change of the magnetic flux, each DC component of voltage, current, and displacement may be reduced from each. The voltage, current, and displacement vector display voltage V, current I, and displacement X obtained by subtracting the direct current component are expressed by the following equation (14). Here, j is an imaginary unit, and e is 2.718.

FIG. 3 shows an equivalent circuit in which the basic waveform generating means 5, the power supply unit 3, and the coil 53 a of the linear motor 50 of the linear compressor 1 of FIG. 1 are connected. In the figure, L and R respectively indicate the inductance and electric resistance of the coil 53a. The voltage V (t) between the terminals of the coil 53a is affected by the counter electromotive force due to the reciprocating motion of the mover 55, and the inductance L and the counter electromotive force coefficient C of the coil 53a are expressed by Equation 15. Here, N is the number of turns of the coil 53a, and Φ is the magnetic flux generated by the coil 53a.

Since the speed is a function of displacement and time, the magnetic flux Φ is a function Φ (I, X) of the current I and the displacement X, and the current I and the displacement X are functions of time. Therefore, since the magnetic flux Φ is affected by the time change of the current and the time change of the displacement of the mover 55, that is, the speed, the voltage V between the terminals of the coil 53a is expressed by the following equation (16) using the equation (15).

Equation 17 is obtained by Equation 14 and Equation 16. Accordingly, the inductance is obtained from the voltage amplitude V _O and the voltage phase θ _V , the current amplitude I _O and the current phase θ _{I at} both ends of the coil, the displacement amplitude X _O and the displacement phase θ _{X of} the movable body 60, that is, the movable element 55 or the piston 58. L and the counter electromotive force coefficient C can be obtained from Equation 17.

When the electrical resistance R of the coil 53a is smaller than the inductance L, the electrical resistance is regarded as 0, and Expression 17 is expressed by Expression 18.

  Note that Equations 3 to 17 hold even when the DC component is zero.

(Control method when the DC component is smaller than the amplitude component)
When the direct current component is smaller than the amplitude component (including amplitude 0), the power source unit 3 is configured so that the voltage and current of the power supplied from the power source unit 3 to the linear motor 50 are smaller than the amplitude component before the measurement. Or by adjusting the direct current component of the basic waveform generating source 5a. Further, as will be described later (FIG. 6), the neutral position of the mover 55 of the linear compressor 2 can be secured by adjusting the thickness of the spacers 73 and 74 provided at one end of the coils 71 and 72. The neutral position can be secured by adjusting the length of the piston 58.

  Further, by supplying power to the coils 53a, 53b, and 53c of the linear motor 50 with a transformer interposed in the output of the power supply unit 3, the coil voltage between the coil terminals and the current flowing through the 53a, 53b, and 53c are reduced to zero. be able to. In this case, what is necessary is just to adjust so that the direct-current component of the displacement of the movable body 60 may become small with respect to an amplitude component.

Since the direct current component U _D of Equation 4 and the direct current component V _D of Equation 6 may be regarded as 0, the basic waveform u (t) and the voltage waveform v (t) are expressed by Equations 19 and 20, respectively. In step 6s, two unknowns, voltage amplitude and voltage phase angle, may be obtained. Accordingly, the first voltage phase angle {(θ _V1 + θ _V ) + P obtained by adding an integer multiple of 2π to the phase angle corresponding to two different measurement timings within one cycle of the frequency of the basic waveform with respect to the common timing. _V (2π)} and the voltage amplitude by solving the number 20 simultaneous binary equations obtained from the voltage values V ₁ and V ₂ measured at the second voltage phase angle {θ _V + Q _V (2π)} Equation 21 is obtained, where V _O and voltage phase θ _V are obtained. Here, P _V and Q _V are integers.

In the current measurement calculation step 7s, since the _ID of Formula 9 may be regarded as 0, the current waveform i (t) is expressed by Formula 22, and two unknowns of the current amplitude and the current phase angle may be obtained. That is, the first current phase angle {(θ _I1 + θ _I ) + P _{I obtained} by adding an integer multiple of 2π to the phase angle corresponding to two different measurement timings within one period of the frequency of the basic waveform with respect to the common timing. (2π)} and the current amplitude I _O by solving the simultaneous binary equation 22 given by the current values I ₁ and I ₂ measured at the second current phase angle {θ _I + Q _I (2π)}. And the equation (23) in which the current phase θ _I is obtained. Here, P _I and Q _I are integers.

In displacement measurement calculation step 6s, few because the X _D of 11 may be regarded as 0 displacement waveform x (t) is indicated by the number 24, the displacement amplitude displacement phase angle may be obtained with two unknowns. That is, a first displacement phase angle {(θ _X1 + θ _X ) + P _X (2π)} obtained by adding an integer multiple of 2π to a phase angle corresponding to two different measurement timings within one period with reference to the common timing. Solving the displacement amplitude X _O and the displacement phase θ by solving the simultaneous binary equation 24 obtained from the displacement values X ₁ and X ₂ measured at the second displacement pressure phase angle {θ _X + Q _X (2π)} _The number 25 from which _I is obtained is obtained. Here, P _X and Q _X are integers.

The measurement timings of the above-described measurement calculation steps 6s, 7s, and 8s must be based on a common common timing, but may be the same or different from each other in each step. The measured values of voltage, current, and displacement are obtained by substituting the measured values obtained by shifting the phase angle by a small amount into Equations (21), (23), and (25), and the amplitudes V _O and I of the displacement. _{O, X O,} the phase angle _{θ V, θ I, θ X} , the DC component _{V D, I D, X D} , is the difference for the case where the phase angle does not deviate is microcrystalline small amounts, measurements of voltage Alternatively, the measured value where the phase angle slightly deviates may be used. Further, when θ _V1 = θ _I1 = θ _{X1 is set} to π / 2 or π, Equations 21, 23, and 25 become simple equations.

In the coil calculation 9s, the coil 53a inductance L and the counter electromotive force coefficient C are obtained. That is, the voltage amplitude V _O and the voltage phase angle θ _V calculated by the equation 21 in the voltage measurement calculation step 6s, the current amplitude I _O and the current phase angle θ _I calculated by the equation 23 in the current measurement calculation step 7s, and the displacement measurement. inductance L and the back electromotive force coefficient C of the coil by substituting the displacement amplitude X _O and displacement phase angle theta _X calculated by the number 25 in the calculation step 8s number 17 is obtained. Since the above-described Equations 17 and 18 exclude the direct current component, this holds true even when the direct current component is smaller than the amplitude component. Therefore, the equation 17 is calculated when the electric resistance R of the coil is considered, and the equation 18 is calculated when the electric resistance R is not considered.

  The inductance and the counter electromotive force coefficient can be obtained by measuring the values measured by the voltage, current, and displacement measuring means 6a, 7a, and 8a using the above-described various arithmetic expressions. May be calculated.

  Next, the effect of the control method of the linear compressor 1 for obtaining the inductance and the counter electromotive force coefficient of the linear motor will be described.

  A basic waveform generating source 5a of the control unit 4 generates a sine wave having a predetermined amplitude or a sine wave basic waveform at a predetermined frequency corresponding to the actual machine operation, and the linear motor is generated by the power source unit 3 based on the basic waveform. The voltage and current of the electric power supplied to 50 are supplied to the linear motor 50 in a state close to the actual machine operating state, and the movable body 60 is reciprocated in a sine wave or sine wave shape. The voltage measurement operation step 6s, the current measurement calculation step 7s, and the displacement measurement calculation step 8s are based on the common timing, and the voltage and current of the coil 53a and the movable body 60 are measured at the measurement timing from each timing means 6d, 7d, 8d. The measured values of the displacements are output by the output means 6b, 7b, 8b. An inductance and a counter electromotive force coefficient are calculated in the coil calculation step 9s from the calculated values obtained by the detection means 6c, 7c, and 8c from the output measurement values, that is, the respective amplitudes and phase angles of voltage, current, and displacement. Therefore, the inductance and the counter electromotive force coefficient of the coils 53a, 53b, 53c of the linear motor 50 in a state close to the actual machine operating state can be obtained, and there is no need to differentiate the measured current of the prior art. Therefore, it is possible to provide a control method for the linear compression apparatus 1 that is not easily affected by electrical noise, has a small burden on a processor that performs arithmetic processing, and can perform highly accurate position control.

(Effect of control method when there is DC component)
When the DC component is included in any of the voltage, current, and displacement of the piston 58 supplied to the coils 53a, 53b, 53c, the voltage measurement in the voltage measurement calculation step 6s and the current measurement in the current measurement calculation step 7s are performed. The measurement and the displacement measurement in the displacement measurement step 8s are measured at a phase angle obtained by adding an integer multiple of 2π to each of three or more different phase angles within one period of the frequency of the basic waveform with reference to the common timing. Then, by calculating the inductance from the calculated values obtained by the respective measurement calculation means 6, 7, and 8, the burden on the processor of the calculation processing is reduced. Furthermore, by increasing the number of measurement points at three or more different phase angles and averaging and calculating the measurement values, the accuracy of the inductance value and the back electromotive force coefficient value is improved, and high-precision piston position control is possible. .

  Further, a basic waveform generating source 5a of the control unit 4 generates a sine wave having a predetermined amplitude or a sine wave (substantially sine wave) basic waveform at a predetermined frequency corresponding to the actual machine operation, and this basic waveform is generated. By inputting and supplying electric power from the power supply unit 3 to the linear motor 50 of the linear compressor 2, the movable body 60, that is, the movable element 55 and the piston 58 have a predetermined frequency and a predetermined amplitude, or a sine wave. Reciprocates in waves. Therefore, when the DC component is included in any of the voltage and current of the power supplied to the coils 53a, 53b, and 53c and the displacement of the piston 58, the number 7 of the voltage measurement calculation step 6s and the number of the current measurement calculation step 7s. 10 and the number 13 of the displacement measurement calculation step 8 s and the number 17 of the coil calculation step 9 s can be used. Therefore, the calculation is performed without using the differentiation and integration used in the prior art, so that it is hardly affected by noise. Highly accurate calculation is possible, the calculation circuit is simple, and the burden on the processor for calculation processing is reduced.

(Effect of control method when DC component is smaller than amplitude component)
When the direct current component of the voltage and current supplied to the coils 53a, 53b, and 53c is small by the amplitude, and the direct current component of the displacement of the piston 58 is small relative to the amplitude component, the direct current components of the voltage, current, and displacement are reduced. By considering it as 0, the voltage measurement calculation step 6s, the current measurement calculation step 7s, and the displacement measurement calculation step 8s are integer multiples of two or more different phase angles within one period of the frequency of the basic waveform with reference to the common timing. The voltage, current, and displacement are respectively measured at the phase angle to which 2π is added, and the respective amplitudes and phase angles of the voltage, current, and displacement can be obtained by calculation by the detection means 6c, 7c, 8c, An inductance and a counter electromotive force coefficient can be calculated from the calculated values. Therefore, the number of processes in each measurement calculation step 6s, 7s, 8s is reduced, the calculation formula used in each detection means 6c, 7c, 8c is simplified, and the burden on the processor of the calculation process is further reduced. By increasing the measurement points of two or more different phase angles and averaging and calculating the measurement values, the accuracy of the inductance value and the counter electromotive force coefficient value is improved, and the piston position can be controlled with high accuracy.

  In addition, the movable body 60 reciprocates at a predetermined frequency with a predetermined amplitude of a sine wave or a sine wave. Therefore, the DC voltage of the power and current supplied to the coils 53a, 53b, and 53c is smaller by the amplitude. When the direct current component of the displacement of the piston 58 is smaller than the amplitude component, the direct current components of the voltage, current, and displacement are regarded as 0, so that the number 21 of the voltage measurement calculation step 6s, the current measurement calculation Since the number 23 of the step 7 s, the number 25 of the displacement measurement calculation step 8 s, and the number 17 of the coil calculation step 9 s can be used, the influence of noise can be obtained by performing the calculation without using the differentiation and integration used in the prior art. The calculation circuit can be performed with high accuracy, the calculation circuit is simple, and the load on the processor for calculation processing is reduced.

(About the electrical resistance of the coil)
In general, the electrical resistance of the coil is designed to be smaller than the inductance of the coil. Therefore, since the inductance L and the counter electromotive force coefficient C can be used in the equation 18, the equation 18 is simpler than the equation 17 and is processed. The burden on the processor is reduced.

FIG. 4 is a circuit diagram of inductance measurement performed conventionally. As shown in FIG. 4, a coil 15 as a specimen is connected to an alternating current source 17, and a voltmeter 18 and an ammeter 16 are provided in the coil 15. In the figure, L represents the inductance of the coil 15, and R represents the electrical resistance of the coil 15. A conventional equation for obtaining the impedance used in the measurement circuit shown in FIG. Here, V is a voltage, I is a current, R is an electric resistance of the coil, f is a frequency, and π is a circular ratio.

  Next, a linear compression device in which the position of the piston is controlled will be described.

  FIG. 5 shows a block diagram of a control circuit of a linear compressor with piston position control according to the present invention. The circuit of FIG. 5 is basically the same as the circuit of FIG. 1 and will be described with respect to differences from FIG. 1. The control circuit 10a of the linear compression apparatus 10 of FIG. The coil calculation means 9 is removed, and a calculation formula specifying means 11, a displacement waveform calculation means 12, and a basic waveform correction means 13 are newly added.

  The control circuit 1a in FIG. 1 and the control circuit 10a in FIG. 5 can be realized by a digital circuit, an analog circuit, or a circuit combining a digital circuit and an analog circuit. Various arithmetic expressions can be realized by a microprocessor and software in the case of a digital circuit, and can be realized by combining an adder, a sine generator, a multiplier, and a divider in the case of an analog circuit. The power supply unit 3 may be an inverter or a power amplifier.

  The operation of the linear compression apparatus 10 in which the position of the piston 58 is controlled will be described with reference to FIG. The operation of the coils 53b and 53c is the same as that of the coil 53a.

(When there is a direct current component)
When at least one of the voltage and current of the coil 53a of the linear motor 50 and the displacement of the piston 58 has a direct current component, the basic waveform generation means 5, the voltage measurement calculation means 6 and the current measurement calculation means 7 The basic waveform generation step 5s, the voltage measurement calculation step 6s, and the current measurement calculation step 7s, except for the displacement measurement calculation step 8s when there is a direct current component of the impedance and counter electromotive force coefficient measurement method shown in FIG. The same processing is performed based on the same arithmetic expression used. The voltage and current measurement timings correspond to three or more different measurement timings within one period of the frequency of the basic waveform with reference to the common timing from the voltage measurement timing means 6d and the current measurement timing 7d. Each measured value of voltage and current is output at a phase angle obtained by adding an integral multiple (2π) to the phase angle.

In the arithmetic expression specifying means 11, various quantities of the arithmetic expression of the displacement x (t) of the piston 58 calculated by the displacement waveform calculating means 12, that is, the voltage amplitude V _O , the voltage phase angle θ _V , the current amplitude I _O , and the current phase. The angle θ _I , the inductance L, the counter electromotive force coefficient C, and the electric resistance R are set as constants.

The calculation formula of the displacement x (t) used in the displacement waveform calculation means 12 is derived as follows. In the equivalent circuit of the coil 53a in FIG. 3, the relationship between the coil voltage v (t), the coil current i (t), and the displacement x (t) is expressed by Equation 27.

In Equation 27, L is an inductance, R is an electric resistance of the coil 53a, and C is a counter electromotive force coefficient. Integrating the speed dx (t) / dt obtained from Equation 27, v (t) and V _D = 0 of Equation 5 above, i (t) of Equation 8, and I _D = 0 over time t A displacement x (t) indicated by 28 is obtained. The integral and derivative terms are not included in x (t) of Equation 28.

In Equation 28, V _O and θ _V are in Equation 7, I _O and θ _I are in Equation 10, L and C are in Equation 17 or Equation 18, X _D is shown in Equation 13, and these constants are given in advance. The measurement is calculated by the steps 6s, 7s, 8s, and 9s shown in FIG. The electrical resistance R is measured in advance with an ohmmeter.

  The displacement waveform calculation means 12 calculates a displacement waveform based on the specified displacement equation of Equation 28.

  The basic waveform correcting means 13 compares the voltage waveform corresponding to the displacement waveform x (t) calculated by the displacement waveform calculating means 12 with the basic waveform u (t) generated by the basic waveform generation source 5a and calculates a deviation value. Then, the basic waveform u (t) is corrected and a deviation signal (operation signal) is transmitted to the power supply unit 3.

  The power supply unit 3 determines the voltage value and current value of the power supplied to the linear motor 50 based on the deviation signal, and when power is supplied to the linear motor 50, an alternating magnetic field is generated in the coils 53a, 53b, and 53c of the linear motor 50. The position of the displacement of the piston 58 is feedback-controlled so as to interact with the magnetic flux of the permanent magnet 56a of the mover 55 and to reciprocate the mover 55 in a sine wave or sine wave having a desired amplitude corresponding to the basic waveform. The gas in the compression space 70 is compressed.

(When DC component is small relative to amplitude)
In this case, the voltage and current measurement timings correspond to two or more different measurement timings within one period of the frequency of the basic waveform with reference to the common timing from the voltage measurement timing means 6d and the current measurement timing 7d. The measured value is output at a phase angle obtained by adding an integral multiple (2π) to the phase angle. Further, in the position control circuit of FIG. 5, the basic waveform generation step 5s, except for the displacement measurement calculation step 8s when the DC component of the impedance and counter electromotive force coefficient measurement method shown in FIG. The same processing is performed based on the same calculation formula used in the voltage measurement calculation step 6s and the current measurement calculation step 7s.

Displacement calculation equation of the displacement x (t) used in the waveform calculating means 12 will number 29 Remove the DC component X _D of displacement of the number 28.

In Equation 29, as described above, V _O and θ _V are expressed by Equation 21, I _O and θ _I are expressed by Equation 23, L and C are expressed by Equation 17 or Equation 18, and these constants are described above in advance. The measurement is calculated by each step 6s, 7s, 8s, 9s. The electric resistance R is also measured in advance, and these quantities are specified as constants by the arithmetic expression specifying means 11. Next, when the displacement waveform x (t) is calculated based on the equation 29 by the displacement waveform calculation means 12, the position of the piston 58 is feedback-controlled as in the case where there is a direct current component.

(About linear compressor)
FIG. 6 is a cross-sectional view of the linear compressor 2 shown in FIGS. 1 and 5. The linear compressor 2 includes a pressure vessel 69, a linear motor 50 fixed to the inner peripheral surface of the pressure vessel 69, a piston 58 disposed on a mover 55 of the linear motor 50, and a piston 58 reciprocatingly moving the gas. And a cylinder portion 65 that forms a compression space 70 for compressing.

  In the pressure vessel 69, the end plate 69b is airtightly fixed to one end of the barrel 69a, and the flange portion 66a of the cylinder block 66 of the cylinder portion 65 is airtightly fixed to the other end.

  The linear motor 50 includes a stator 51 fixed to the inner peripheral surface of the barrel 69 a and a mover 55 that is driven by a magnetic flux generated by the stator 51. The stator 51 is provided with a holder 54a, a coil 53a wound in the circumferential direction of the barrel 62a, a core 52 in which a plurality of magnetic steel plates 52a are laminated at both axial ends of the coil 53a, and the outer sides of the two cores 52. Provided with holders 54b and 54c and coils 53b and 53c wound in the circumferential direction of the barrel 69a.

  The mover 55 is made of a cylindrical permanent magnet 56a fixed to the center of the hat-shaped holder 57, a non-magnetic spacer 56b provided at both ends of the permanent magnet 56a, and a magnetic material fixed via the spacer 55b. The yokes 56c, 56d and a spring holder 56e provided at the end of the yoke 56c are configured. The rod holder 61 is provided on the closed inner side of the holder 57, and the rod 59 passes through a hole at the center of the rod holder 61, and one end is fixed with a nut 62, and the other end is fixed with a piston 58. The piston 58 and the mover 55 are integrated with each other via a rod 59 to form a movable body 60.

  The cylinder portion 65 is composed of a cylinder block 66 and a cylinder liner 67. The Linder block 66 is composed of a large tube portion 66b, flange portions 66a provided at both ends of the large tube portion 66b, and a small tube portion 66c through which the rod 59 passes. Become. The cylinder liner 67 is mounted on the inner peripheral surface of the large cylinder portion 66b, and a head 68 having a pipe 68a through which gas flows in and out is provided at one end, and the head 68 is airtightly fixed to the flange portion 66a. The head 68, the cylinder liner 67, and the piston 58 form a compression space 70 in which gas is compressed.

  The piston 58 is slidably circumscribed with a predetermined minute gap with respect to the cylinder liner 67, and the rod 59 is attached to the hole of the small cylinder portion 66c with a gap. The holder 57 is slidably inscribed with a small gap with respect to the outer peripheral surface of the small tube portion 66c.

  Coil springs 71, 72 are provided at both ends of the mover 55, a combined spring in which the coil springs 71, 72, the magnetic spring of the permanent magnet 56 a and the gas spring generated by the reciprocating motion of the piston 58, and the mass of the movable body 60 A vibration system is formed. Further, the mover 55 maintains a predetermined gap with respect to the inner peripheral surface of the core 52, and the coil springs 71 and 72 so that the intermediate position in the axial direction of the permanent magnet 55a and the intermediate position of the two cores 52 are aligned in the stopped state. The length of the piston 58 on the head side is adjusted so that the piston 58 is disposed at the neutral position in this state. By adjusting in this way, each phase angle corresponding to each of two or three or more different measurement timings within one period of the frequency of the basic waveform with reference to the common timing is an integer multiple (2π ) Can be used to measure and calculate voltage, current, and displacement.

  When measuring the inductances and back electromotive force coefficients of the coils 53a, 53b, 53c of the linear motor 50, a displacement sensor 75 indicated by a one-dot chain line is disposed at the center of the end plate 69b, and the displacement of the movable body 60 (piston 58 and The displacement of the mover 55 is measured. When the position of the piston 58 of the linear compressor 2 is controlled, the displacement sensor 75 need not be provided.

  The linear compressor 2 is used, for example, in a Stirling refrigerator, and the pressure vessel 69 is filled with, for example, helium. By applying a sine wave or sinusoidal voltage to the linear motor 50, an alternating magnetic flux is applied to the stator 51. The alternating magnetic flux causes the mover 55 to reciprocate integrally with the piston 58, so that the compression and expansion of helium are repeated in the compression space 70 to reciprocate in the pipe 68a. Although not shown in FIG. 6, a linear compressor in which a suction valve and a discharge valve are provided in the head 68 is used for a split-type pulse tube refrigerator, a GM refrigerator, or the like.

  Next, the effect of the linear compression apparatus 10 that controls the position of the piston 58 will be described.

By supplying sine wave or sine wave power to the coils 53a, 53b, 53c of the linear motor 50, the movable body 60 having the piston 58 on the mover 55 is reciprocated in a sine wave or sine wave form. do. Therefore, it is obtained by measuring the voltage and current at a phase angle obtained by adding an integer multiple of 2π to a phase angle corresponding to three or more different timings within one period of the frequency of the basic waveform with reference to the common timing. Using the measured values and the measured values of the inductances of the coils 53a, 53b, 53c and the counter electromotive force coefficient obtained in the state close to the actual machine operation, without using the differentiation and integration included in the arithmetic expression of the prior art. can be Ru determined by calculating the displacement waveform of 58. Based on a deviation signal (operation signal) obtained by comparing the displacement waveform obtained by this calculation with the basic waveform and correcting the basic waveform by the basic waveform correcting means 13, the voltage of the power supplied to the coils 53a, 53b, 53c by the power source unit 3 Since the phase is determined and the linear motor 50 is driven to feedback control the position of the piston 58, the position detector of the piston 58 is unnecessary, the burden on the processor that performs the arithmetic processing is small, and it is not easily affected by electrical noise. Thus, the low-cost linear compressor 10 that can perform highly accurate piston position control can be provided.

Coil 53a of the linear motor 50, 53b, a DC component voltage amplitude amount small fence of the power of the voltage supplied to 53c, small DC component of the current with respect to the amplitude component, the DC component of the displacement of the piston 58 to the amplitude component On the other hand, by adjusting the voltage and current of the power supply unit and the positions of the mover 55 and the piston 58 of the linear compressor 2 in advance so as to be small, the frequency is reduced to 2 within one period of the frequency of the basic waveform with reference to the common timing. A voltage and current are measured at a phase angle obtained by adding 2π which is an integer multiple to a phase angle corresponding to two or more different timings, and a displacement waveform of the movable body 60 is conventionally calculated based on each measured value. The calculation is performed without using differentiation and integration included in the calculation formula of the technology, and the displacement waveform obtained by this calculation is fed back in the same manner as described above to control the position of the movable body 60. Therefore, it is possible to provide a low-cost linear compression apparatus 10 that does not require a position detector for the piston 58, is lightly burdened by a processor that performs arithmetic processing, is not easily affected by electrical noise, and can perform highly accurate piston position control. Furthermore, since the number of processes of the processor is reduced, the burden on the processor is reduced.

Further, the direct current component of the power voltage supplied to the coils 53a, 53b, and 53c of the linear motor 50 is small in amplitude, the direct current component in current is small relative to the amplitude component, and the direct current component of the displacement of the piston 58 is the amplitude component. If it is smaller than the actual machine operating state, it is obtained by calculating the displacement waveform of the piston 58 using the inductance values of the coils 53a, 53b, 53c and the back electromotive force coefficient value obtained by measurement and calculation in a state close to the actual operating state, and feedback. By controlling the position of the movable body 60, the accuracy of the displacement waveform of the piston 58 is increased, and the linear compression device 10 with a highly accurate piston position control can be realized.

  Hereinafter, the control method of the linear compressor 1 for obtaining the inductance and the counter electromotive force coefficient of the embodiment and the verification test result verifying the validity of the linear compressor 10 whose position is controlled by the piston will be described with reference to FIG. To do. FIG. 7 is a diagram showing a control method of the linear compressor 1 for obtaining the inductance and the counter electromotive force coefficient in a linear compressor having dimensions different from those in FIG. 6 and a verification test result in which piston position control is applied. is there. In the figure, the horizontal axis indicates time t, and the vertical axis indicates voltage, current, and displacement. In the figure, (1) is the measured value of the supply voltage, (2) is the calculated value of the supplied voltage, (3) is the measured value of the supplied current, (4) is the calculated value of the supplied current, and (5) is the piston displacement. Measured value, (6) shows each waveform of the calculated value of piston displacement. The frequency of the supply voltage is 29 Hz, which is close to the resonance frequency of the piston displacement.

  As can be seen from FIG. 7, (1) of the measured value of the supply voltage and (2) of the calculated value of the supply voltage, (3) of the measured value of the supplied current and (4) of the calculated value of the supplied current, respectively. The waveforms of (5) of the measured value of the piston displacement and (6) of the calculated value of the piston displacement substantially overlap with each other and are calculated with high accuracy.

The block diagram of the control circuit regarding the control method of the linear compressor concerning this invention is shown. The voltage vector diagram explaining the calculation formula of the voltage amplitude and voltage phase which are derived | led-out from the voltage measurement value of a coil is shown. 2 shows an equivalent circuit in which a basic waveform generating means, a power supply unit, and a coil of a linear motor of the linear compression device of FIG. 1 are connected. 1 shows a prior art inductance measurement circuit. The block diagram of the control circuit of the linear compressor which carried out piston position control is shown. Fig. 6 shows the linear compressor shown in Figs. 1 and 5. The control method of the linear compressor which calculates | requires the inductance and back electromotive force coefficient of this invention, and the verification test result of piston position control are shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 10 Linear compressor 2 Linear compressor 3 Power supply part 4 Control part 5 Basic waveform generation means 5s Basic waveform generation step 6 Voltage measurement calculation means 6s Voltage measurement calculation step 7 Current measurement calculation means 7s Current measurement calculation step 8 Displacement measurement calculation Means 8s Displacement measurement calculation step 9 Coil calculation means 9s Coil calculation step 12 Displacement waveform calculation means 13 Basic waveform correction means 50 Linear motor 53a, 53b, 53c Coil 55 Movable element 58 Piston 60 Movable body 65 Cylinder part

Claims (1)

A linear motor including a linear motor having a movable body having a piston disposed on a mover and a coil, and a cylinder portion in which the piston reciprocates to compress gas;
A power source for supplying electric power to the coil of the linear motor and reciprocating the movable body of the linear compressor in a sine wave or sine wave;
A control method for a linear compression apparatus comprising:
A basic waveform generating step of generating the basic waveform by a basic waveform generating means for generating a sine wave or a sine wave basic waveform to be sent to the power supply unit;
By means of voltage measurement calculation means for measuring and calculating the voltage of the power, 2π (360 °) which is an integral multiple of three or more different voltage phase angles within one period of the frequency of the basic waveform with reference to a common timing. When the DC component of the voltage is small relative to the amplitude with the added phase angle, 2π which is an integer multiple is added to two or more different voltage phase angles within one period of the frequency with reference to the common timing. A voltage measurement calculation step for measuring the voltage at a phase angle and calculating a voltage amplitude and a voltage phase angle of a voltage waveform from the measured voltage value;
From the current measurement calculation means for measuring and calculating the current of the electric power, with a phase angle obtained by adding 2π of an integer multiple to three or more different current phase angles within one period of the frequency based on the common timing, Alternatively, when the direct current component of the current is small with respect to the amplitude, the current is set at a phase angle obtained by adding 2π which is an integral multiple of two or more different current phase angles within one period of the frequency with reference to the common timing. A current measurement calculation step for measuring and calculating the current amplitude and current phase angle of the current waveform from the measured current value;
A phase angle obtained by adding an integral multiple of 2π to three or more different displacement phase angles within one period of the frequency with reference to the common timing by a displacement measurement calculation means for measuring and calculating the displacement of the piston; or When the DC component of the displacement is smaller than the amplitude, the displacement is measured at a phase angle obtained by adding 2π which is an integral multiple of two or more different displacement phase angles within one period of the frequency with reference to the common timing. A displacement measurement calculation step for calculating a displacement amplitude and a displacement phase angle of the displacement waveform from the measured displacement value;
By means of coil calculation means for calculating based on the calculation results obtained from the measured values of the voltage, the current and the displacement, the voltage amplitude, the voltage phase angle, the current amplitude, the current phase angle, and the displacement amplitude, From the displacement phase angle, the inductance of the coil and a coil calculation step of calculating a counter electromotive force coefficient of the coil, and obtaining the inductance and the counter electromotive force coefficient in advance,
A control unit that controls the voltage or current of the power of the power supply unit;
During operation of the linear compression device, the control unit generates a sine wave or a sine wave basic waveform to be sent to the power supply unit, and within one cycle of the frequency of the basic waveform based on a common timing. The phase angle is obtained by adding an integer multiple of 2π to three or more different voltage phase angles, or within one period of the frequency of the basic waveform with reference to the common timing when the DC component of the voltage is small relative to the amplitude. Voltage measurement calculation means for measuring a voltage flowing through the coil at a phase angle obtained by adding 2π which is an integer multiple to two or more different voltage phase angles, and calculating a voltage amplitude and a voltage phase angle of a voltage waveform from the measured voltage values When,
With the phase angle obtained by adding an integer multiple of 2π to three or more different current phase angles within one period of the frequency with reference to the common timing, or when the DC component of the current is small relative to the amplitude, the common timing The current flowing through the coil is measured at a phase angle obtained by adding an integer multiple of 2π to two or more different current phase angles within one period of the frequency, and the current amplitude of the current waveform is calculated from the measured current value. Current measurement calculation means for calculating a current phase angle;
A displacement waveform computing means for computing a displacement waveform of the movable body from the voltage waveform obtained by the voltage measurement computing means and the current waveform obtained by the current measurement computing means;
Comparing the basic waveform and the displacement waveform obtained by the displacement waveform calculating means, the basic waveform correcting means for transmitting the operation signal corrected the basic waveform to the power supply unit,
A control method for a linear compression device, wherein the displacement waveform calculation means calculates the displacement waveform based on the inductance and the counter electromotive force coefficient obtained in the coil calculation step to control the position of the movable body.

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