JP2023023406A - Linear motor control device and suspension system equipped with the same, and linear motor control method - Google Patents

Abstract

To provide a linear motor control device suitable for a wide range of pressure conditions.SOLUTION: The present invention includes: a linear motor 104 composed of an armature 9 having a coil to which an AC voltage is applied, and a movable element 6 that moves relatively with the armature 9; a resonance spring 23 connected to one side of the movable element 6; and a control unit 102 that controls the linear motor 104. A piston that reciprocates in a cylinder 1a is connected to the other side of the movable element 6. The control unit 102 includes pressure state determination means 109 that determines a pressure state in the cylinder 1a according to one of a phase difference between an applied voltage of the coil 8 and a current, a phase difference between the applied voltage of the coil 8 and a position of the movable element 6, a q-axis current value, and a current amplitude. The control unit 102 has a control mode in which an amplitude of the voltage applied to the coil 8 and a center position of the reciprocation of the movable element 6 are changed based on the pressure state determined by the pressure state determination means 109.SELECTED DRAWING: Figure 1

Description

The present invention relates to a linear motor control device, a suspension system having the same, and a linear motor control method.

As a system using a linear motor, there is a technique described in Patent Document 1, for example. Patent Document 1 discloses a phase detection means for detecting a phase difference between an output voltage detected by a voltage detection means and a current detected by a current detection means, and a value corresponding to the phase difference detected by the phase detection means. Control means are disclosed for correcting the output voltage of the AC power supply to maintain the neutral position of the piston at a predetermined position.

Japanese Patent No. 3869481

The technology described in Patent Document 1 provides a linear compressor driving device that can maintain a constant neutral position of the piston even if the load fluctuates and does not complicate the configuration of the linear compressor. are doing.

However, since Patent Document 1 assumes a mechanism for compressing expanded refrigerant gas in a cooling device such as a refrigerator, it does not assume a situation where the suction pressure of the compressor is higher than the discharge pressure. Further, in the technology described in Patent Document 1, the viewpoint of flow rate is not taken into consideration.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a linear motor control device, a suspension system having the same, and a linear motor control method that can handle a wide range of pressure conditions.

In order to achieve the above objects, the present invention provides a linear motor comprising an armature having a winding to which an alternating voltage is applied, and a mover that moves relative to the armature, and a linear motor connected to one of the movers. and a controller for controlling the linear motor, wherein a fluid machine is connected to the other side of the mover, and the controller controls the voltage applied to the winding and the pressure state determination means for determining the pressure state of the fluid machine according to any one of a current phase difference, a phase difference between the voltage applied to the winding and the position of the mover, a q-axis current value, and a current amplitude; The part is characterized by comprising a control mode for varying the amplitude of the voltage applied to the windings and the center position of the reciprocating motion of the mover based on the pressure state determined by the pressure state determining means.

ADVANTAGE OF THE INVENTION According to this invention, the linear motor control apparatus which can respond to a wide range of pressure conditions, a suspension system provided with the same, and a linear motor control method can be provided.

1 is a schematic diagram of a linear motor control device 100 according to Embodiment 1 of the present invention; FIG. 1 is a perspective view of a linear motor 104 according to Example 1 of the present invention; FIG. 3 is a cross-sectional view in a plane along line III-III of FIG. 2; FIG. FIG. 10 is a diagram showing the thrust applied to the mover 6 due to the magnetization of the magnetic pole teeth 70; 4 is a schematic diagram showing a state in which an external mechanism is connected to the mover 6 of the linear motor 104; FIG. 4 is a diagram showing the relationship between the frequency of an alternating voltage (horizontal axis) and the stroke (vertical axis) of a mover 6 when alternating voltages having the same amplitude are applied; FIG. 7A shows the relationship between the position and speed of the mover 6 when the linear motor 104 is driven, and FIG. 7B shows the relationship between the applied voltage waveform and the motor current flowing through the linear motor 104. FIG. It is a figure which shows. FIG. 8 is a diagram showing the AC waveform of FIG. 7 as a vector; 2 is a vertical cross-sectional view showing an example of a hermetic compressor 50 having a linear motor 104. FIG. 1 is a diagram showing a system configuration example using a hermetic compressor 50 having a linear motor 104 as a power source; FIG. FIG. 5 is a diagram showing an example of pressure changes over time when the hermetic compressor 50 is operated with air having different pressures previously put into tanks on the suction side and the discharge side. It is a figure which shows the example of the relationship between differential pressure (pressure difference of discharge pressure and suction pressure) and resonance frequency. FIG. 7 is a diagram showing an example of analysis results of changes in discharge pressure and discharge flow rate when suction pressure is changed; 3 is a diagram illustrating the configuration of a voltage command value generator 103; FIG. 3 is a diagram showing a configuration example of an offset voltage calculator 180; FIG. FIG. 4 is a diagram showing a second configuration example of an offset voltage calculator 180; 3 is a diagram showing a configuration example of pressure state determination means 109. FIG. FIG. 5 is a diagram showing an example of change in phase difference dltθ with respect to pressure difference; FIG. 10 is a diagram showing a second configuration example of the pressure state determination means 109a; FIG. 10 is a diagram showing a third configuration example of the pressure state determination means 109b; It is a figure which shows the example of the relationship between a load state and resonance frequency. It is a figure which shows the example of the relationship between a load state, a stroke command value, and a voltage amplitude value. FIG. 7 is a diagram showing an example of analysis results of changes in discharge pressure and discharge flow rate when suction pressure is changed; FIG. 5 is a diagram showing the circuit configuration of an air suspension system 200 according to Embodiment 2 of the present invention; FIG. 2 is a schematic diagram of a vehicle 300 equipped with an air suspension system 200 according to Embodiment 2 of the present invention; It is a configuration example of an offset voltage calculator 180a according to Example 2 of the present invention. FIG. 9 is a diagram showing an example of change in output voltage according to Example 2 of the present invention;

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Similar components are denoted by similar reference numerals, and the same description will not be repeated.

The various constituent elements of the present invention do not necessarily exist independently of each other, and a plurality of constituent elements may be formed as one member, and one constituent element may be formed by a plurality of members. , that a component is part of another component, part of one component overlaps part of another component, and so on.

In this embodiment, for convenience of explanation, terms such as the front-back direction, the left-right direction, and the up-down direction, which are orthogonal to each other, are used. It can be parallel to one direction or the other.

<Linear motor controller 100>
FIG. 1 is a schematic diagram of a linear motor control device 100 according to Embodiment 1 of the present invention. A linear motor control device 100 comprises a control section 102 , a linear motor 104 , a power conversion circuit 105 and a current detection means 107 . As will be described later, the linear motor 104 has an armature 9 and a mover 6 that move relative to each other.

The control unit 102 outputs an output voltage command value to the power conversion circuit 105 or a drive signal (pulse signal) for driving the power conversion circuit 105 according to the detection result of the voltage command value generator 103 . The control unit 102 also has a pressure state determination means 109 and a PWM signal generator 133 .

Although details are omitted, the power conversion circuit 105 is an example of a power conversion unit that converts the voltage of a DC voltage source and outputs an AC voltage. For example, it can be configured using a widely used voltage-type PWM inverter. A DC current source may be used instead of the DC voltage source.

<Linear motor 104>
FIG. 2 is a perspective view of the linear motor 104 according to Example 1 of the present invention. The linear motor 104 of this embodiment has a mover 6 (see FIG. 3) that can move relative to the armature 9 in the direction of the arrow in FIG. The armature 9 has two magnetic poles 7 facing each other across an air gap and a winding 8 wound around the magnetic poles 7 . The mover 6 is arranged in this gap. The magnetic pole 7 has magnetic pole teeth 70 as end faces facing the mover 6 .

The armature 9 can apply a longitudinal force (hereinafter referred to as thrust) to the mover 6 . For example, as will be described later, the thrust can be controlled so that the mover 6 reciprocates in the front-rear direction.

The mover 6 has two plate-shaped permanent magnets 2 (2a, 2b) that are vertically magnetized. In FIG. 2, the permanent magnets 2a and 2b are shown, but the mover 6 is not shown. As the mover 6, for example, a plate-like one to which the plate-like permanent magnet 2 is fixed can be used.

In this embodiment, the configuration of the mover 6 having one armature 9 and two permanent magnets 2 is shown. There is no particular limit to the number. Also, the number of phases of the power conversion circuit 105 can be freely determined according to the number of armatures 9 .

The control unit 102 can output a drive signal so that the mover 6 reciprocates within a range facing the armature 9 .

FIG. 3 is a cross-sectional view in a plane taken along line III--III in FIG. The arrow lines in FIG. 3 show an example of magnetic flux lines when an AC voltage is applied to the two windings 8 and a current is caused to flow. The direction of magnetic flux flow can be reversed depending on the direction of the current flowing through the winding 8, so it is not limited to that shown in the figure. The magnetic flux lines magnetize the magnetic pole teeth 70 .

[Thrust applied to mover 6]
FIG. 4 is a diagram showing the thrust applied to the mover 6 by the magnetization of the magnetic pole teeth 70. As shown in FIG. The polarities of the magnetic pole teeth 70 caused by the current flowing through the winding 8 are represented by "N" and "S" near the magnetic pole teeth 70 in the figure.

In FIG. 4A, the upper magnetic pole tooth 70a is magnetized to "S" and the lower magnetic pole tooth 70b is magnetized to "N", so that the permanent magnet 2a is attracted and the mover 6 receives a forward force. , shows an example in which the mover 6 has moved forward. In FIG. 4B, the upper magnetic pole tooth 70a is magnetized to "N" and the lower magnetic pole tooth 70b is magnetized to "S". An example in which the mover 6 has moved backward is shown.

Thus, by applying a voltage or current to the winding 8, magnetic flux is supplied to the magnetic circuit including the two magnetic poles 7, and the two opposing magnetic pole teeth 70 (magnetic pole tooth group) can be magnetized. By applying an AC voltage or current, such as a sine wave or a rectangular wave (square wave), as the voltage or current, it is possible to give a thrust to reciprocate the mover 6 . Thereby, the motion of the mover 6 can be controlled.

The thrust applied to the mover 6 can be changed by changing the amplitude of the applied AC current or AC voltage. Further, by appropriately changing the thrust applied to the mover 6 using a known method, the displacement of the mover 6 can be changed as desired. Here, when the mover 6 makes a reciprocating motion (for example, motion that sequentially repeats the magnetization of the magnetic pole teeth 70 as shown in FIGS. 4(a) and 4(b)), the displacement of the mover 6 that changes in the form of an AC waveform is The amount of change is called a stroke. In this embodiment, forward displacement of the mover 6 is defined as positive.

Since the magnetic pole tooth 70 is a magnetic material, a magnetic attraction force that attracts the permanent magnet 2 acts on the magnetic pole tooth 70 . In this embodiment, since the two magnetic pole teeth 70 are arranged to face each other with the mover 6 interposed therebetween, the resultant force of the magnetic attraction force acting on the mover 6 can be reduced.

<Purpose of this embodiment>
The details of the configuration example will be described later, but the purpose of this embodiment is to provide a suitable configuration and drive control when used as a power source for the fluid machine. Efficiency and flow rate are generally used as evaluation indices for fluid machinery, and it can be said that the purpose of this embodiment is to improve efficiency and increase flow rate.

[Mechanism outside mover 6]
FIG. 5 is a schematic diagram showing a state in which an external mechanism is connected to the mover 6 of the linear motor 104. As shown in FIG. In FIG. 5, as an example, a mechanism is provided in which an external mechanism configured by a resonance spring 23 (elastic body) as a coil spring is connected to one side of the mover 6 and the mover 6 is returned by the spring force. The resonance spring 23 has one end connected to one side of the mover 6 via the intermediate portion 24 and the other end fixed to the base portion 25 . Further, a side portion 26 that extends substantially parallel to the extending direction of the resonance spring 23 and guides or supports the resonance spring 23 is provided. The other end of the mover 6 is connected to, for example, a piston 4 as a fluid machine (compression element 20) (see FIG. 9).

When the linear motor 104 is reciprocated, acceleration and deceleration are repeated each time the moving direction of the mover 6 changes. During deceleration, the velocity energy of the mover 6 is converted into electrical energy (regenerative operation), but the resistance of the wiring to the linear motor 104 causes loss.

On the other hand, when a resonance spring 23 (assist spring) is added to the mover 6 as shown in FIG. The velocity energy of the element 6 can be effectively utilized, and a highly efficient linear motor drive system can be constructed. A known elastic body may be used instead of the resonance spring 23 .

FIG. 6 is a diagram showing the relationship between the frequency of the alternating voltage (horizontal axis) and the stroke of the mover 6 (vertical axis) when the alternating voltage of the same amplitude is applied. As can be seen from FIG. 6, the stroke of the mover 6 sharply increases near the resonance frequency (approximately 50 Hz), and the stroke decreases away from the resonance frequency. The resonance frequency is given by the square root of the value obtained by dividing the spring constant k of the resonance spring 23 by the mass m of the mover 6, but depending on the system of the linear motor 104, this value may be an approximate value.

In this manner, by applying an AC voltage having a resonance frequency or a frequency in the vicinity thereof, it is possible to vibrate with a large stroke (large energy). That is, high efficiency can be realized. In this way, when controlling the linear motor 104 in which an elastic body such as the resonance spring 23 is added to the mover 6 , it is important to detect or estimate the resonance frequency of the mover 6 . It is also important to detect or estimate the resonance frequency of the mover 6 when controlling the stroke of the mover 6 as desired.

[Phase relationship when driving]
7A shows the relationship between the position and speed of the mover 6 when the linear motor 104 is driven, and FIG. 7B shows the relationship between the applied voltage waveform and the motor current flowing through the linear motor 104. FIG. It is a figure which shows. FIG. 8 is a diagram showing the AC waveform of FIG. 7 as a vector. It can be seen that the speed of the mover 6, the applied voltage, and the motor current are almost in phase.

Further, when a resonance spring 23 is added to the mover 6 and the mover 6 is reciprocated at a mechanical resonance frequency determined by the mass of the mover 6 and the spring constant, the phase of the position of the mover 6 is the winding 8 It is known that there is a phase difference of 90 degrees with respect to each of the phases of the voltage V applied to , the motor current Im, and the speed of the mover 6 . That is, when any one of these relationships holds, it can be estimated that the motor is driven at the resonance frequency. FIG. 8 shows the relationship between the position of the mover, the speed of the mover, the applied voltage, and the motor current as a vector.

If the mass of the mover 6 deviates from the assumption due to manufacturing variations, or if the state of the load element added to the mover 6 (the state of the load when viewed from the linear motor 104) changes, the mass connected to the resonance spring 23 changes, the resonance frequency changes. Therefore, it is preferable to accurately detect or estimate the resonance frequency that changes depending on the conditions.

<Hermetically sealed compressor 50>
FIG. 9 is a longitudinal sectional view showing an example of a hermetic compressor 50 having a linear motor 104. As shown in FIG. The hermetic compressor 50 is a reciprocating compressor in which the compression element 20 and the electric element 30 are arranged inside the hermetic container 3 . The compression element 20 and the electric element 30 are elastically supported inside the sealed container 3 by a support spring 49 . Electric element 30 includes mover 6 and armature 9 .

The compression element 20 includes a cylinder block 1 forming a cylinder 1a, a cylinder head 16 assembled on the end face of the cylinder block 1, and a head cover 17 forming a discharge chamber space. The working fluid supplied into the cylinder 1a is compressed by the reciprocating motion of the piston 4, and the compressed working fluid is sent to a discharge pipe (not shown) communicating with the outside of the compressor. For example, a valve element made of an elastic material may be provided between the cylinder and the discharge chamber space so that the pressure in the cylinder is substantially equal to or higher than the pressure in the discharge space. When the pressure inside the cylinder is lower than the pressure in the discharge space, the valve body closes to prevent reverse flow (flow from the discharge side to the suction side).

A piston 4 is connected to the other end of the mover 6 . In this embodiment, the working fluid is compressed by the reciprocation of the mover 6 and the piston 4 . A compression element 20 is arranged at one end of the electric element 30 . The cylinder block 1 has a guide rod along the front-rear direction for guiding the reciprocating motion of the mover 6 .

When installing the linear motor 104 in the sealed container 3, an airtight connector called a hermetic connector or a hermetic seal may be used. To maintain hermeticity, it is desirable to minimize the number of connectors. Therefore, it is important to configure the position and resonance frequency of the mover 6 without a sensor, but this point is not mentioned in this specification, and any known technique can be applied.

When a resonance spring 23 (not shown in FIG. 9) is added to the mover 6 and the mover 6 is reciprocated at a mechanical resonance frequency determined by the mass and spring constant of the mover 6, the resonance frequency of the compression element 20 is It is also necessary to consider the impact on That is, the pressure in the discharge space causes the working fluid to act like a spring, so that the frequency at which the resonance occurs changes. That is, when the pressure of the cylinder 1a is high, it is equivalent to the spring constant of the resonance spring 23 added to the mover 6 being high, and the resonance frequency is increased. Conversely, when the pressure in the cylinder 1a is low, the spring constant of the resonance spring 23 added to the mover 6 becomes dominant, and the resonance frequency is the mechanical resonance frequency determined by the mass and spring constant of the mover 6. close to

As described above, the evaluation indexes of the hermetic compressor 50 generally include efficiency and flow rate. Efficiency needs to be considered for each of the compression element 20 and the electric element 30, but is ultimately determined by multiplying the efficiencies of both elements. Simply speaking, the flow rate can be obtained by multiplying the stroke amount of the piston 4 (which can also be considered as the stroke amount of the mover 6) and the frequency of the piston reciprocating motion.

Using the linear motor 104 as the electric element 30 has the advantage that the stroke of the piston can be controlled by the voltage applied to the linear motor 104 . By controlling the stroke, it has the advantage that the volume of the electric element 30 can be changed.

<Linear Compressor System>
FIG. 10 is a diagram showing a system configuration example using a hermetic compressor 50 powered by a linear motor 104. As shown in FIG. FIG. 10 shows a configuration example in which a suction pipe 53a and a discharge pipe 53b are connected to the suction side and the discharge side of a hermetic compressor 50, and a first tank 52a and a second tank 52b are connected to the ends of the pipes 53. . The working fluid (including gas) compressed by the hermetic compressor 50 is not particularly limited, but air will be described as an example here. As for the operation of the system configuration example shown in FIG. 10, the air stored in the first tank 52a is moved to the second tank 52b.

Here, the configuration in which the tanks 52 are added to both the suction side and the discharge side is shown, but this is only an example. For example, a system in which the tanks are not connected to the discharge side is naturally conceivable. It is a system to move to the second tank 52b.

In such a system that compresses or moves the working fluid into the tank, not only the efficiency and power consumption during the compression operation are important, but also the amount of movement of the working gas per unit time, that is, the flow rate. Furthermore, from the point of view of the system, small size and light weight are desired. By making it smaller, the degree of freedom in installation increases, and the materials required for manufacturing can be reduced.

FIG. 11 is a diagram showing an example of pressure changes over time when the hermetic compressor 50 is operated with air having different pressures previously put into the respective tanks on the suction side and the discharge side. In this example, immediately after the start of operation, the suction pressure (the pressure in the first tank 52a) is higher than the discharge pressure (the pressure in the second tank 52b), the pressure difference gradually decreases, and at a certain point (about 25 sec), the pressure reverses (suction pressure < discharge pressure), and the pressure difference increases. For example, it shows an example of a system in which the operation is stopped when the discharge pressure reaches a desired pressure.

FIG. 12 is a diagram showing an example of the relationship between differential pressure (pressure difference between discharge pressure and suction pressure) and resonance frequency. Again, when the discharge pressure is high, this is equivalent to a high spring constant of the resonance spring 23 added to the mover 6, and the resonance frequency increases. When the differential pressure is small, the resonance frequency is close to the resonance frequency determined by the resonance spring and the mover mass. When the differential pressure is negative (the suction pressure is higher than the discharge pressure), the air flows out even if the piston does not compress. Therefore, the resonance frequency is lowered.

FIG. 13 is a diagram showing an example of analysis results of changes in the discharge pressure and the discharge flow rate when the suction pressure is changed with respect to the flow rate, which is the evaluation index of the compressor described above. As a power source for the piston 4, although details are omitted, two types are used: a reciprocating type (DC motor drive) in which the rotary motion of a DC motor is converted to reciprocating motion by a crankshaft or the like, and the linear motor 104 of this embodiment. It is the result of comparing the flow rate by drive system.

For simplicity of explanation, if the stroke amount of the reciprocating type and the linear type is constant, when the discharge pressure is high, the resonance frequency is high, that is, the driving frequency (the frequency of the piston reciprocating motion) is also high. The discharge flow rate of the linear type is greater than that of the reciprocating type. Conversely, when the discharge pressure is low, the discharge flow rate of the linear type is lower than that of the reciprocating type.

Therefore, another object of the present invention is to provide a linear motor control device that achieves a high efficiency and a high flow rate under a wide range of suction pressure and discharge pressure conditions. A configuration example thereof will be described below.

<Overview of Control Unit 102>
The control unit 102 and the like will be described with reference to FIG. 1 and the like. The control unit 102 has a voltage command value generator 103 , a pressure state determination means 109 and a PWM signal generator 133 . The control unit 102 applies power to the linear motor 104 so that the linear motor 104 operates according to a stroke command and a frequency command given from a higher control (not shown) or obtained by holding or calculation in the control unit 102 The basic operation is to control the voltage applied.

<Voltage command value generator 103>
FIG. 14 is a diagram for explaining the configuration of the voltage command value generator 103. As shown in FIG. A phase command value θ*, which will be described later, and a stroke command value l* and a frequency command value ω* obtained from a host controller (not shown) or the like are input to the voltage command value generator 103, and a single-phase alternating current is generated. A voltage command value Vm* is output.

As can be seen from the configuration of FIG. 14, the voltage applied to the linear motor 104 can be adjusted by changing any one of the stroke command value l*, the frequency command value ω*, and the offset voltage Voff. can be done. That is, by adjusting the amplitude, frequency, and offset value of the applied voltage, it is possible to control the drive frequency to the resonance frequency and control the stroke. This makes it possible to optimize efficiency (power consumption) and flow rate.

In this embodiment, a stroke command value l* obtained from a host controller (not shown) or the like and a frequency command value ω* following the resonance frequency are input. A known method can be applied to obtain the frequency command value ω* that follows the resonance frequency. For example, it can be configured by means described in Japanese Patent No. 6591668.

The stroke command value l* has two meanings: the amplitude of the reciprocating motion of the piston (or mover) and the amount of displacement on the positive side (the direction in which the piston compresses the working fluid) and on the negative side. Use properly by.

The frequency command value ω* is integrated by the integrator 94a to obtain the phase command value θ*. *) is obtained. A multiplier 92d multiplies this cosine by the stroke command value l*. By doing so, the speed command value vm* of the mover 6 can be obtained without performing a differential operation. In general, one of the position command value xm* and speed command value vm* can be a sine and the other can be a cosine. In addition, depending on the combination of sine and cosine, it is necessary to add a negative sign.

Further, the speed command value vm* of the mover 6 is multiplied by the induced voltage constant Ke* in a multiplier 92e to obtain a single-phase AC voltage command value Vm0*. After that, the offset voltage output by the offset voltage calculator 180 is added to obtain the AC voltage command value Vm* to be applied to the linear motor 104 .

In addition to the above, the voltage command value generator 103 can apply a known drive voltage command method for a synchronous motor.

<Offset voltage calculator 180>
FIG. 15 is a diagram showing a configuration example of the offset voltage calculator 180. As shown in FIG. The offset voltage calculator 180 outputs an offset voltage Voff according to the pressure state. In FIG. 15, the horizontal axis indicates the input pressure state, and the vertical axis indicates the output offset voltage Voff. In FIG. 15, for example, information of differential pressure [MPa] is used as the pressure state on the horizontal axis, and the offset voltage Voff on the vertical axis is based on the DC voltage of the DC voltage source when the AC voltage is output by the power conversion circuit 105. This is an example of a case of expressing by a ratio.

In a region where the differential pressure is negative (suction pressure>discharge pressure) and the absolute value is small, the offset voltage Voff is negative. The offset voltage Voff is assumed to be zero in other pressure states. By doing so, the flow rate can be increased in a region where the differential pressure is negative (suction pressure>discharge pressure) and the absolute value of the pressure difference is small. By making the offset voltage Voff negative, the center position of the reciprocating motion of the mover 6 can be shifted to the anti-piston side. An increase in the stroke on the negative side can be considered equivalent to an increase in the maximum capacity of the compressor.

As the stroke on the negative side increases, the working fluid supplied from the suction pipe 53a into the cylinder 1a increases. Since the differential pressure is negative (suction pressure > discharge pressure) and the absolute value is small, the valve body opens as soon as the piston starts moving in the direction of compression (positive stroke direction), and the working fluid begins to flow. That is, even if the total stroke length is the same, by applying a negative offset voltage Voff to increase the stroke on the negative side, the flow rate can be increased without lowering the efficiency.

As described above, the resonance frequency is low in the operating state where the differential pressure is negative (suction pressure>discharge pressure) and the absolute value is small. In order to increase the flow rate in this operating region, increasing the stroke length or increasing the drive frequency are conceivable, but neither is desirable from the viewpoint of efficiency. When the stroke length is increased, the sliding distance is increased by that amount, so the sliding loss increases. Also, it is easy to understand that increasing the driving frequency results in driving outside the resonance frequency, which reduces the efficiency.

In the example of FIG. 15, the differential pressure is a curve near -0.2 and 0.0, but it does not have to be a curve. may be changed linearly with a minimum value at .

Although the horizontal axis in FIG. 15 represents the pressure state, a plurality of means for detecting the pressure state are conceivable. As described above, the means using the pressure sensor, the means using the phase difference between the applied voltage and the current flowing through the linear motor, the means using the q-axis current substantially proportional to the thrust of the linear motor 104, and the means using the amplitude of the current flowing through the linear motor 104 are It is possible to adopt the means to use, etc.

FIG. 16 is a diagram showing a second configuration example of the offset voltage calculator 180. As shown in FIG. FIG. 16 shows a configuration example for switching the offset voltage Voff in accordance with a load state mode signal output by pressure state determination means 109, which will be described later. An example of the relationship between the load state and the load state mode signal can be as shown in FIG. That is, the region where the pressure difference between the suction pressure and the discharge pressure is negative (suction pressure > discharge pressure) and the absolute value of the pressure difference is large is the first load state mode (1), and the pressure difference between the suction pressure and the discharge pressure is negative ( Suction pressure>discharge pressure) and the pressure difference absolute value is small is the second load state mode (2). Mode (3). Then, for example, the offset values for load condition modes (1) and (3) are set to zero, and the offset value for load condition mode (2) is set to a negative value. The pressure difference in the first load condition mode (1) is greater than the pressure difference in the second load condition mode (2). A first control mode signal (1) and a second control mode signal corresponding to the first load state mode (1), the second load state mode (2), and the third load state mode (3) (2) output the third control mode signal (3) from the offset voltage calculator 180; The second load state mode (2) may include the time when the suction pressure and the discharge pressure are equalized (suction pressure=discharge pressure).

<Pressure state determination means 109>
FIG. 17 is a diagram showing a configuration example of the pressure state determination means 109. As shown in FIG. FIG. 17 shows a phase difference detector 130 that outputs the phase difference between the mover position Xm or the motor current Im and the reference phase (for example, the phase obtained by integrating the frequency command value ω* shown in FIG. 14). It is an example of a configuration. When the phase obtained by integrating the frequency command value ω* shown in FIG. 14 is used as the reference phase θ*, the phase difference between the movable element position Xm or the motor current Im with respect to the applied voltage is obtained. . A plurality of combinations are conceivable depending on how to obtain the reference phase θ* and the denominator and numerator when obtaining the arctangent. For example, FIG.

In the example of FIG. 18, the phase difference in the pressure equalization state (suction pressure and discharge pressure are substantially the same) is 90°, and the phase difference dltθ increases or decreases according to the pressure difference. In other words, this is an example in which the pressure state determination means 109 is configured by utilizing the fact that the phase difference dltθ changes according to the load state determined by the pressure conditions of suction and discharge. When the offset voltage calculator 180 has the configuration shown in FIG. 16, the pressure difference is determined according to the preset phase difference dltθ, and the first load state mode (1) and the second load state mode are selected. (2) to output the signal of the third load state mode (3);

FIG. 19 is a diagram showing a second configuration example of the pressure state determination means 109a. This configuration example uses the load current detector 150, and the load current detector 150 of the present embodiment extracts the amplitude of the load current component using a Fourier transform formula.

The load current detector 150 has a sine calculator 81 that outputs the sine of the input value and a cosine calculator 82 that outputs the cosine of the input value, similarly to the configuration of the phase difference detector 130 shown in FIG. , a phase command value .theta.* as a reference phase is input, and the sine and cosine for the phase command value .theta.* are obtained. A multiplier 92 outputs a value obtained by multiplying each of the sine and cosine by the motor current Im. When the outputs are integrated by integrators 94e and 94f, respectively, first-order Fourier coefficients of sine and cosine are obtained. That is, since frequency components higher than the driving frequency ω of Fourier expansion can be eliminated, the configuration can be robust against high-order noise.

The outputs of the integrators 94 e and 94 f are squared and input to the square root operator 96 . That is, the square root of the sum of the squares of the sine and cosine components, which are the first-order Fourier coefficients of the sine and cosine, respectively, is obtained to obtain the amplitude of the fundamental current. Since the amplitude of the fundamental wave current increases as the load increases, the load current Im_ld can be detected with the configuration in FIG. In this embodiment, the load current is assumed to be equivalent to the q-axis current (current approximately proportional to the torque of the rotary motor or the thrust of the linear motor) generally used in drive control of the rotary motor. That is, it changes according to the load state determined by the pressure conditions of suction and discharge. It is negative when suction pressure>discharge pressure, and positive when suction pressure<discharge pressure. This is an example in which the pressure state determining means 109a is configured using this relationship. When the offset voltage calculator 180 has the configuration shown in FIG. 16, it outputs a control mode signal according to a preset load current value Im_Id.

FIG. 20 is a diagram showing a third configuration example of the pressure state determination means 109b. The load current detector 150a receives the motor current Im and extracts the cos component (Im_cos) of the fundamental frequency of the motor current Im. Next, the cos component (Im_cos) of the fundamental frequency of the motor current Im is low-pass filtered by the first-order lag filter 141 and output as the load current Im_ld.

Although FIG. 20 shows a configuration example of the first-order lag filter, the low-pass filter is not limited to the first-order lag filter, and other known configurations such as a second-order lag filter may be used.

As shown in FIGS. 7 and 8, when the position of the mover is a sine wave, the cosine component of the load current is dominant. Therefore, the configuration of FIG. 20 can detect the load current by filtering the extracted cosine component. The configuration of FIG. 20 is effective in reducing the computational load.

As described above, since the working fluid exerts a spring-like action, the frequency at which the resonance state occurs changes depending on the pressure state. Therefore, FIG. 21 shows an example of configuring the pressure state determination means 109 using this relationship.

FIG. 21 is a diagram showing an example of the relationship between load state and resonance frequency. Although details are not shown in this embodiment, the estimated or detected resonance frequency is compared with a predetermined judgment value, and the first load state mode (1), the second load state mode (2), and the third load state mode (2) are selected. Determine load condition mode (3). That is, when the drive frequency of the mover is close to the resonance frequency determined by the resonance spring and the mover mass and lower than the reference value, it is determined as the second load state mode (2), and the negative offset voltage is set. Give and drive.

[Output voltage waveform]
In the configuration of the voltage command value generator 103 shown in FIG. 14, the amplitude of the AC voltage command value Vm* is proportional to the stroke command value l* when the induced voltage constant Ke* is a constant value. Therefore, the stroke command value l* (that is, the amplitude of the AC voltage command value Vm*) is changed as shown in FIG.

The vertical axis of FIG. 22 indicates the maximum stroke or the DC voltage of the DC voltage source of the power conversion circuit 105 as a reference (100%). That is, a minute voltage is output in the first load state mode (1). The first load state mode (1) is a region where the pressure difference between the suction pressure and the discharge pressure is negative (suction pressure>discharge pressure) and the absolute value is large. That is, in this region, the valve body is open due to the differential pressure. Therefore, the stroke command value l* should be determined so that the minimum voltage, current, or stroke required for the pressure state determination means 109 to determine the pressure state. In the first load state mode (1), the voltage command value generator 103 outputs a signal (voltage command value) for the first control mode so as to reduce the amplitude of the voltage applied to the windings. .

In the second load state mode (2), the pressure difference between the suction pressure and the discharge pressure is negative (suction pressure>discharge pressure). Although a large stroke is not required as in , the stroke command value l* is gradually increased as the pressure difference disappears, taking into consideration the characteristics of the elastic body that constitutes the valve body. In the second load state mode (2), as described above, the offset voltage calculator 180 outputs a negative offset value (a value that shifts the center position of the reciprocating motion of the mover 6 toward the anti-piston side). In the second load state mode (2), a signal ( voltage command value). The second control mode may include the time when the suction pressure and the discharge pressure are equalized.

In the third load state mode (3), the pressure difference between the suction pressure and the discharge pressure is positive (suction pressure < discharge pressure). A stroke command value l* is given so as to increase functionally (chain line). In the third load state mode (3), the amplitude of the voltage applied to the windings from the voltage command value generator 103 increases substantially proportionally (solid line) according to the load state, or exponentially. A signal (voltage command value) for the third control mode is output so that the amplitude of the voltage applied to the windings increases in line with (chain line).

FIG. 23 is a diagram showing an example of analysis results of changes in discharge pressure and discharge flow rate when the suction pressure is changed using the above configuration. While the results are the same as in FIG. 13 when the discharge pressure is higher than the suction pressure, it can be seen that the flow rate can be increased when the suction pressure is higher than the discharge pressure.

As described above, the pressure state of the fluid machine can be determined based on the phase difference between the voltage applied to the windings and the current, or the phase difference between the voltage applied to the windings and the mover position, the q-axis current value, or the current amplitude. can be done. By controlling the offset voltage and voltage amplitude value according to the determined pressure state, it is possible to provide a linear motor control device and control method that achieves high efficiency and high flow rate under a wide range of suction pressure and discharge pressure conditions. can.

Next, Example 2 will be described. The configuration of this embodiment can be the same as that of the first embodiment except for the following points. This embodiment relates to an air suspension system as an example of a device equipped with the linear motor control device 100. FIG.

FIG. 24 is a circuit diagram showing an air suspension system 200 according to Embodiment 2 of the present invention. FIG. 25 is a schematic diagram of a vehicle 300 equipped with an air suspension system 200 according to a second embodiment of the invention. However, with regard to the air suspension system 200 according to FIG. 25, only a distribution point 209N, which will be described later, and components on the side of the air suspensions 201 and 202 from this point are shown.

The air suspension system 200 includes two air suspensions 201, 202, a compressor 203 driven by a linear motor 104, an intake filter 204, a first tank 205, an air dryer 207, and three check valves 208, 215, 217 as valves. , a supply/discharge switching valve 210 , two suspension control valves 211 and 212 , a return passage opening/closing valve 214 , and an exhaust passage opening/closing valve 219 . The air suspension system 200 connects them by passages through which air can flow.

The air suspension system 200 is, for example, mounted on a vehicle 300 and is a system that controls air pressure in air chambers 201C and 202C of air suspensions 201 and 202 . For example, a left wheel 310L and a right wheel 310R of the vehicle 300 are provided with an axle 320 that connects these hubs. For example, air suspensions 201 and 202 are provided between the wheels 310 and the vehicle body 330, such as between the left wheel 310L and the right wheel 310R and the vehicle body 330, or between the hub and the vehicle body 330. The vehicle height can be adjusted by controlling the air pressure.

The air suspensions 201 and 202 may be attached between the axle 320 on the wheel 310 side and the vehicle body 330 of the vehicle 300 as shown in FIG. (wheel 310 side) and the vehicle body 330, or between the hub of the wheel 310 (wheel 310 side) and the vicinity of the vehicle body 330 mounting portion of the upper arm of the suspension (body 330 side). In this way, the air suspensions 201 and 202 may be provided so as to support the wheels 310 and the vehicle body 330. For example, they can be provided between the wheels 310 and the vehicle body 330 in the vertical direction, and directly support the wheels 310 and the vehicle body. 330 is not limited.

In this embodiment, an air suspension system 200 having two air suspensions will be described, but the number of air suspensions included in the air suspension system 200 is not particularly limited as long as it is one or more. The number of air suspensions can be equal to the number of wheels, for example. For example, in the case of a four-wheeled vehicle, a total of four air suspensions, two on the two front wheel sides and two on the two rear wheel sides, can be arranged. In this embodiment, an example in which the buffer cylinders 201A, 201A and the air chambers 201C, 202C serving as air springs are integrated is shown. (Hydraulic shock absorbers) 201A and 202A and air springs may be provided independently.

In the air suspensions 201, 202, air chambers 201C, 202C are formed between damping cylinders 201A, 202A and piston rods 201B, 202B, respectively, to constitute air springs. Each of the air chambers 201C and 202C is connected to a passage, which will be described later, and the air suspension system 200 operates to control the pressure and vehicle height.

The compressor 203 can compress the air sucked from the intake port 203C and discharge it from the discharge port 203D. The compressor 203 is composed of a compressor body 203A and a linear motor 203B. A pressure sensor is provided to measure the pressure of the suction port 203C, the discharge port 203D, or both ports.

The air intake filter 204 is provided at an outside air intake through which the air suspension system 200 can take in outside air (atmosphere) as needed, and removes dust and the like in the outside air when the air suspension system 200 takes in outside air. be able to.

The first tank 205 can, for example, compress air with the compressor 203 and store the compressed air.

The air dryer 207 holds a desiccant such as silica gel inside, and can reduce the humidity of the air passing through the air dryer 207 .

The air suspension system 200 has a supply/exhaust passage 209, a supply passage 206, a return passage 213, a bypass passage 216, and an exhaust passage 218 as passages.

The supply/discharge passage 209 (209A, 209B, 209C) has a first end at the air suspension 201, a second end at the air suspension 202, and a third end at the supply/discharge switching valve 210. , and suspension control valves 211 and 212 are provided.

The supply/discharge passage 209 has a distribution supply/discharge passage 209A, a distribution supply/discharge passage 209B, and a joint supply/discharge passage 209C, each of which has one end connected to each other at a distribution point 209N. The distribution supply/discharge passage 209A has one end connected to the distribution point 209N and the other end connected to the air chamber 201C. The distribution supply/discharge passage 209B has one end connected to the distribution point 209N and the other end connected to the air chamber 202C. The joint supply/discharge passage 209C has one end connected to the distribution point 209N and the other end connected to the supply/discharge switching valve 210 .

The replenishment passage 206 is a passage having a first end at the supply/discharge switching valve 210 and a second end at the discharge port 203D of the compressor 203. The first tank 205, the air dryer 207 and the first check valve 208 is provided.

A bypass end point 216B is located in the supply passage 206 on the opposite side of the air dryer 207 from the discharge port 203D. A second end of the bypass passage 216 is connected to the bypass end point 216B.

In the replenishment passage 206, an exhaust starting point 218A is located on the same side of the air dryer 207 as the discharge port 203D. A first end of the exhaust passage 218 is connected to the exhaust starting point 218A.

A first tank 205 is located between the first end of the refill passage 206 and the first check valve 208 .

Air dryer 207 is located between bypass end point 216B and exhaust start point 218A. The air suspension system 200 can bypass the compressor 203 and exhaust the air in the air chambers 201C and 202C to the atmosphere. At this time, since the air flows through the bypass passage 216 and the exhaust passage 218, the dry air in the air chambers 201C and 202C flows, and the moisture in the desiccant in the air dryer 207 can be removed.

A first check valve 208 is located between the bypass endpoint 216 B and the first tank 205 . A first check valve 208 allows air to flow from the second end of the make-up passage to the first end and blocks the reverse flow. This prevents the air in the first tank 205 from flowing into the compressor 203 and the exhaust passage 218 .

The suction side passage 220 is a passage having a first end at the suction port 203C and a second end at the outside air intake, and is provided with a second check valve 215 .

A return end point 213B is positioned between the suction port 203C of the suction side passage 220 and the second check valve 215 . A second end of the return passage 213 is connected to the return end point 213B.

An exhaust endpoint 218B is located between the second check valve 215 and the ambient air intake. A second end of the exhaust passage 218 is connected to the exhaust endpoint 218B.

A second check valve 215 is located between the return endpoint 213B and the exhaust endpoint 218B. The second check valve 215 allows air to flow from the second end side of the suction side passage 220 to the first end side and blocks the reverse. As a result, the air in the air chambers 201C and 202C that has passed through the return passage 213 and the return passage open/close valve 214 can be prevented from being exhausted from the outside air intake port and guided to the intake port 203C.

The return passage 213 is a passage having a first end at the supply/discharge switching valve 210 and a second end at the return end point 213B, and a return passage opening/closing valve 214 is provided.

In the return passage 213, the bypass start point 16A is located between the supply/discharge switching valve 210 and the return passage opening/closing valve 214. As shown in FIG. A first end of the bypass passage 216 is connected to the bypass starting point 216A.

The bypass passage 216 is a passage having a first end at a bypass start point 216A and a second end at a bypass end point 216B, and a third check valve 217 is arranged.

The third check valve 217 allows air to flow from the first end side of the bypass passage 216 to the second end side and blocks the reverse. As a result, the air discharged from the discharge port 203D can be effectively guided to the first tank 205. As shown in FIG.

The exhaust passage 218 is a passage having a first end at an exhaust start point 218A and a second end at an exhaust end point 218B, and an exhaust passage opening/closing valve 219 is provided.

Exhaust passage 218 may be adapted to exhaust air from a location other than the outside air intake without having a second end connected to exhaust end point 218B, but as in the present embodiment, exhaust end point 218B is connected to the outside air intake. If it is provided between the port and the second check valve 215 , the air exhausted through the return passage 213 , the bypass passage 216 and the exhaust passage 218 can remove dust adhering to the intake filter 204 .

As described above, in addition to check valves 208, 215 and 217, air suspension system 200 includes supply/discharge switching valve 210, two suspension control valves 211 and 212, return passage opening/closing valve 214, and exhaust passage opening/closing valve 219. have.

The supply/discharge switching valve 210 is a 3-port, 2-position electromagnetic valve that connects to three passages and can switch between two types of connections.

The supply/discharge switching valve 210 is connected to the first end of the supply passage 206 , the first end of the return passage 213 , and the third end of the supply/discharge passage 209 .

The supply/discharge switching valve 210 has two positions, connecting the first end of the supply passage 206 and the third end of the supply/discharge passage 209, and connecting the first end of the return passage 213 and the supply/discharge passage. 209, the first end of the return passage 213 and the third end of the supply/discharge passage 209, and the first end of the replenishment passage 206. and a discharge position (b) that blocks the third end of the supply/discharge passage 209 . The position can be switched, for example, by switching the excitation state of the solenoid 210A. In this embodiment, when the solenoid 210A is not energized, the supply/discharge switching valve 210 is held in the discharge position (b) by the spring 210B, and when the solenoid 210A is energized, the supply/discharge switching valve 210 is held in the supply position (a) against the spring 210B. ).

A suspension control valve 211 is provided between the distribution point 209N and the air suspension 201, and a suspension control valve 212 is provided between the distribution point 209N and the air suspension 202.

The suspension control valve 211 is a 2-port, 2-position solenoid valve that connects to two passages and can switch between two types of connections.

The suspension control valve 211 has two positions: an open position (a) that opens the distribution supply/exhaust passage 209A to enable supply and discharge of air from the air chamber 201C, and a closed position (a) that closes the distribution supply/discharge passage 209A to close the air chamber 201C. and a closed position (b) for blocking air supply and exhaust. The position can be switched by switching the excitation state of the solenoid 211A, for example. In this embodiment, when the solenoid 211A is not energized, the suspension control valve 211 is held in the closed position (b) by the spring 211B, and when the solenoid 211A is energized, the suspension control valve 211 is held in the open position (a) against the spring 211B. is switched to

Like the suspension control valve 211, the suspension control valve 212 is a 2-port, 2-position solenoid valve, and can perform the same opening/closing control as the suspension control valve 211 for the distribution supply/discharge passage 209B. These two suspension control valves 211 and 212 may be controlled simultaneously or independently.

Like the suspension control valves 211 and 212, the return passage opening/closing valve 214 is a 2-port 2-position solenoid valve, and opens and closes between the bypass start point 216A and the return end point 213B of the return passage 213 in the same manner as the suspension control valves 211 and 212. can be controlled.

The exhaust passage opening/closing valve 219 is a 2-port 2-position electromagnetic valve like the suspension control valves 211 and 212 and the return passage opening/closing valve 214. , 212 and the return passage opening/closing valve 214 can be controlled.

By changing the configuration as follows, instead of the suspension control valves 211 and 212 provided in the supply/discharge passage 209, the same number of supply/discharge switching valves 210 as the number of air suspensions, that is, 3-port 2-position valves may be used. Specifically, the first end of the replenishment passage 206 is branched in the same number as the number of air suspensions (two in this embodiment) and connected to each of the supply/discharge switching valves 210 . The first end of the return passage 213 is also branched into the same number as the number of air suspensions and connected to each supply/discharge switching valve 210 . Further, one end of each distribution supply/discharge passage (two in this embodiment) is connected to each supply/discharge switching valve 210 instead of the distribution point 209N.

When the configuration is changed as described above, it becomes possible to exhaust air from the other air suspensions while supplying air to one or more of the air suspensions.

Further, if the system configuration is simple, the suspension control valves 211 and 212 may be eliminated, and a throttle may be provided in the distribution supply/exhaust passage 209B.

When a resonance spring 23 is added to the mover 6 of the linear motor 203B and the mover 6 is reciprocated at a mechanical resonance frequency determined by the mass and spring constant of the mover 6, the compression element 20 also affects the resonance frequency. need to consider. That is, due to the suction pressure of the compression element 20 and the pressure of the discharge space, a spring-like action of the working fluid is applied, so that the frequency at which the resonance state occurs changes. That is, when the pressure of the cylinder 1a is high, it is equivalent to the spring constant of the resonance spring 23 added to the mover 6 being high, and the resonance frequency is increased. Conversely, when the pressure in the cylinder 1a is low, the spring constant of the resonance spring 23 added to the mover 6 becomes dominant, and the resonance frequency is the mechanical resonance frequency determined by the mass and spring constant of the mover 6. close to

As described above, when the linear motor 203B is used as the power for the compression element, the resonance frequency changes depending on the conditions of the compression element (suction pressure, discharge pressure, pressure difference between suction and discharge, etc.). Therefore, it is necessary to change the drive frequency according to changes in load and resonance frequency. Further, it can be said that the purpose of this embodiment is to provide a configuration and drive control suitable for increasing the flow rate in order to shorten the time for controlling the vehicle height.

FIG. 26 is a configuration example of the offset voltage calculator 180a according to the second embodiment of the present invention. FIG. 27 is a diagram showing an example of change in output voltage according to Example 2 of the present invention.

As in the first embodiment, the region where the pressure difference between the suction pressure and the discharge pressure is negative (suction pressure>discharge pressure) and the absolute value of the pressure difference is large is called the first load state mode (1). The area where the pressure difference is negative (suction pressure > discharge pressure) and the absolute value of the pressure difference is small is the second load state mode (2), and the area where the pressure difference between the suction pressure and the discharge pressure is positive (suction pressure < discharge pressure). The third load state mode (3) is selected. Then, for example, the offset values for load condition modes (1) and (3) are set to zero, and the offset value for load condition mode (2) is set to a negative value. The pressure difference in the first load condition mode (1) is greater than the pressure difference in the second load condition mode (2). A first control mode signal (1) and a second control mode signal corresponding to the first load state mode (1), the second load state mode (2), and the third load state mode (3) (2) Output the third control mode signal (3) from the offset voltage calculator 180 in the voltage command value generator 103 . The second load state mode (2) may include the time when the suction pressure and the discharge pressure are equalized (suction pressure=discharge pressure).

As in the first embodiment, in the first load state mode (1), a signal ( voltage command value).

In the second load state mode (2), as described above, the offset voltage calculator 180 outputs a negative offset value (a value that shifts the center position of the reciprocating motion of the mover 6 toward the anti-piston side). In the second load state mode (2), a signal ( voltage command value). The second control mode may include the time when the suction pressure and the discharge pressure are equalized.

In the third load state mode (3), the pressure difference between the suction pressure and the discharge pressure is positive (suction pressure < discharge pressure). A stroke command value l* is given so as to increase functionally. In the third load state mode (3), a signal from the voltage command value generator 103 to set the third control mode so that the amplitude of the voltage applied to the winding increases substantially proportionally according to the load state. (voltage command value) is output.

In the second embodiment, by controlling the offset voltage and voltage amplitude value based on the vehicle height information controlled by the operation of the air suspension system 200, high efficiency and high performance can be achieved under a wide range of suction pressure and discharge pressure conditions. It is possible to provide a linear motor controller that achieves flow rate.

The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations.

Further, each of the configurations, functions, processing units, processing procedures, etc. described above may be realized by hardware, for example, by designing a part or all of them using an integrated circuit. Moreover, each of the above configurations, functions, etc. may be realized by software by a processor interpreting and executing a program for realizing each function.

Although the linear motor 104 has been described as a single-phase machine, the configuration of the present invention can be applied to a three-phase machine, and similar effects can be obtained.

DESCRIPTION OF SYMBOLS 1... Cylinder block 1a... Cylinder, 2... Permanent magnet, 3... Closed container, 4... Piston, 6... Mover, 7... Magnetic pole, 8... Winding, 9... Armature, 20... Compression element, 23... Resonance Spring (assist spring) 30 Electric element 50 Hermetic compressor 100 Linear motor controller 102 Control unit 103 Voltage command value generator 104 Linear motor 105 Power conversion circuit 107 ... current detection means, 109 ... pressure state determination means

Claims (10)

A linear motor composed of an armature having a winding to which an AC voltage is applied, a mover that moves relative to the armature, an elastic body connected to one of the movers, and the linear motor are controlled. A linear motor control device comprising a control unit that
A fluid machine is connected to the other of the movers,
The controller controls the pressure state of the fluid machine according to any one of the phase difference between the voltage applied to the winding and the current, the phase difference between the voltage applied to the winding and the position of the mover, the q-axis current value, and the current amplitude. Provided with pressure state determination means for determining
The control unit has a control mode for varying the amplitude of the voltage applied to the windings and the central position of the reciprocating motion of the mover based on the pressure state determined by the pressure state determining means. linear motor controller. In claim 1,
A linear motor control device, wherein the fluid machine is a compressor comprising a cylinder and a piston connected to the other of the movers and reciprocating within the cylinder. In the linear motor control device according to claim 2,
The control mode is
a first control mode in which the amplitude of the voltage applied to the winding is reduced when the suction pressure is higher than the discharge pressure;
When the suction pressure and the discharge pressure are equal, and/or when the suction pressure is higher than the discharge pressure and the pressure difference between the suction pressure and the discharge pressure is smaller than the pressure difference in the first control mode, the center of the reciprocating motion of the mover. A linear motor controller characterized by a second control mode in which a voltage is applied to the windings with an offset value that shifts the position to the anti-piston side. In the linear motor control device according to claim 2,
The control mode is
a first control mode in which the amplitude of the voltage applied to the winding is reduced when the suction pressure is higher than the discharge pressure;
When the suction pressure and the discharge pressure are equal, and/or when the suction pressure is higher than the discharge pressure and the pressure difference between the suction pressure and the discharge pressure is smaller than the pressure difference in the first control mode, the center of the reciprocating motion of the mover. a second control mode in which a voltage is applied to the winding with an offset value that shifts the position to the anti-piston side;
A linear motor controller characterized by a third control mode in which the voltage amplitude increases in proportion to the pressure difference between the suction pressure and the discharge pressure. In claim 2,
A first tank and a second tank are connected to the compressor,
The first tank is connected via a suction pipe,
A linear motor control device, wherein the second tank is connected via a discharge pipe. A linear motor composed of an armature having a winding to which an AC voltage is applied, a mover that moves relative to the armature, an elastic body connected to one of the movers, and the linear motor are controlled. A linear motor control device comprising a control unit that
A piston that reciprocates within the cylinder is connected to the other of the movers,
The control unit controls the pressure state in the cylinder according to any of the phase difference between the voltage and current applied to the windings, the phase difference between the voltage applied to the windings and the position of the mover, the q-axis current value, and the current amplitude. Provided with pressure state determination means for determining
When the suction pressure is higher than the discharge pressure in the pressure state determined by the pressure state determining means, the control section applies a voltage to the winding with an offset value that shifts the center position of the reciprocating motion of the mover to the side opposite to the piston. A linear motor control device characterized by applying voltage. A suspension system provided between the vehicle body and the wheels,
A suspension system comprising the linear motor control device according to any one of claims 1 to 5. A linear motor composed of an armature having a winding to which an AC voltage is applied, a mover that moves relative to the armature, an elastic body connected to one of the movers, and the linear motor are controlled. A linear motor control method comprising a control unit that
A piston that reciprocates within the cylinder is connected to the other of the movers,
The control unit controls the pressure state in the cylinder according to any of the phase difference between the voltage and current applied to the windings, the phase difference between the voltage applied to the windings and the position of the mover, the q-axis current value, and the current amplitude. is determined, and control is performed in a control mode in which the amplitude of the voltage applied to the windings and the central position of the reciprocating motion of the mover are varied based on the determined pressure state. The linear motor control method according to claim 8,
The control mode is
a first control mode in which the amplitude of the voltage applied to the winding is reduced when the suction pressure is higher than the discharge pressure;
When the suction pressure and the discharge pressure are equal, and/or when the suction pressure is higher than the discharge pressure and the pressure difference between the suction pressure and the discharge pressure is smaller than the pressure difference in the first control mode, the center of the reciprocating motion of the mover. A linear motor control method, wherein a voltage is applied to the windings in a second control mode with an offset value that shifts the position to the side opposite to the piston. The linear motor control method according to claim 8,
The control mode is
a first control mode in which the amplitude of the voltage applied to the winding is reduced when the suction pressure is higher than the discharge pressure;
When the suction pressure and the discharge pressure are equal, and/or when the suction pressure is higher than the discharge pressure and the pressure difference between the suction pressure and the discharge pressure is smaller than the pressure difference in the first control mode, the center of the reciprocating motion of the mover. a second control mode in which a voltage is applied to the winding with an offset value that shifts the position to the anti-piston side;
A linear motor control method, characterized in that the control mode is a third control mode in which the voltage amplitude increases in proportion to the pressure difference between the suction pressure and the discharge pressure.

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