JP2951812B2 - Liquid supply device and control method therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure control liquid supply apparatus, and more particularly to a liquid supply apparatus in which a hunting is prevented by changing a target value when controlling a target state by changing a driving state. Related to the device.

[0002]

2. Description of the Related Art For example, a system described in Japanese Patent Application Laid-Open No. 59-65591 and Japanese Patent Application No. 4-42820 has been studied as a pressure control liquid supply device using an inverter. Regarding the control circuit, for example,
Japanese Patent Application Laid-Open No. 65591 and Japanese Patent Application No. 4-42820 have been studied, and the following control is performed.

Control method (1): As described in JP-A-59-65591, the similarity law H1 between the discharge pressure ratio (H1 / H2) of the pump and the rotational speed ratio (N1 / N2) of the pump is used. / H2 = (N1 / N2) ² (Equation 1) Since the rotation speed of the pump and the discharge pressure are in one-to-one correspondence, the rotation speed is set in advance with respect to the target pressure. Alternatively, the target pressure is controlled by setting the number of rotations by calculation. This is a control that simply decelerates the target pressure if it is larger than the target pressure and increases the speed if it is smaller than the target pressure. This includes discharge pressure constant control and terminal pressure constant control (JP-A-59-54797).

Control method (2): Equation (1), similarity rule between pump discharge flow ratio (Q1 / Q2) and pump discharge pressure ratio (H1 / H2) Q1 / Q2 = H1 / H2 (Equation 2) ) Is a method of performing control using.

Control method (3): In the flow rate control, (Equation 1) and (Equation 2), the discharge flow rate ratio (Q1 / Q2) of the pump, and the sectional area ratio (Av1 /
This is a method of performing control using the similarity rule of Av2) Q1 / Q2 = Av1 / Av2 (Equation 3).

In both cases, the control is performed by changing the rotation speed of the pump.

[0007]

As described above, when the control is performed by changing the rotation speed of the pump, when the difference between the target value and the current value is small, the current value is easily controlled to be the target value. It is gaining. However, when the difference between the target value and the current value is large, for example, when the pump is restarted or the amount of water used transiently increases or decreases, hunting occurs due to control delay. SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid supply device and a control method thereof, in which a pump can be driven without hunting even when a difference between an actual pump discharge pressure and a preset discharge pressure target value is large. It is in.

[0008]

The object of the present invention is to provide an auxiliary target value between the output of the discharge pressure detecting means and the target value of the discharge pressure in accordance with the output of the discharge pressure detecting means. When the difference between the output of the detection means and the auxiliary target value is equal to or less than a predetermined value and the difference between the discharge pressure target value and the discharge pressure of the pump is equal to or more than a predetermined value, the output of the discharge pressure detection means is again Auxiliary target value setting means for gradually setting the auxiliary target value closer to the discharge pressure target value by providing a new auxiliary target value corresponding to the output of the discharge pressure detection means between the discharge pressure target value and Means for controlling the output of the discharge pressure detecting means to match the auxiliary target value. Further, as the control method, a first step of providing an auxiliary target value between the discharge pressure target value and the discharge pressure according to a deviation between an actual pump discharge pressure and the discharge pressure target value; A second step of controlling the pump discharge pressure to be an auxiliary target value, and when a deviation between the pump discharge pressure and the auxiliary target value is equal to or less than a predetermined value, the pump discharge pressure and the discharge pressure target value. When the difference between the first and second steps is equal to or more than a predetermined value, the step is repeated by repeating the first step and the second step.

[0009]

When the difference between the actual pump discharge pressure and the preset discharge pressure target value is large, an auxiliary target value corresponding to the pump discharge pressure is provided between the pump discharge pressure and the discharge pressure target value. It was made. If the auxiliary target value is stabilized, it is compared again with the discharge pressure target value. However, if the difference is still large, hunting is caused by repeating the setting of the auxiliary target value. Instead, the pump discharge pressure can be controlled to match the discharge pressure target value.

[0010]

FIG. 1 is a view showing a liquid supply apparatus according to an embodiment of the present invention, which is an example for controlling a pump discharge pressure. The liquid supply device 1 includes a pump 2, a pump driving device (for example, an electric motor) 3, and a control amount data detecting unit (for example, a pressure sensor for detecting a pump discharge pressure) for detecting a control amount of the pump.
And a control panel 5 having a built-in control circuit having a motor transmission (for example, an inverter (not shown)) and a microcomputer (not shown) for controlling the motor transmission. As a hardware configuration of this control circuit, for example, those described in Japanese Patent Application Laid-Open No. Sho 59-65591 and Japanese Patent Application No. 4-42820 are used.

FIG. 2 shows a flowchart of the control. The differences between the first to fifth embodiments described below are the subroutine 1 and the subroutine 2, and the subroutine is illustrated for each embodiment. An example of a control operation time chart is similarly illustrated for each embodiment. Hereinafter, the contents of the control will be described by taking the control of the discharge pressure as an example.

In the configuration as shown in FIG. 1, the control amount data detecting means 4 is a pressure sensor for generating an electric signal E according to the pressure. The current pump discharge pressure H is obtained by step 1 in FIG.
Is detected by the pressure sensor 4, and the electric signal E is taken into the microcomputer. In step 2, the current pump discharge pressure H is compared with a control target value H0. Here, in order to achieve control stability or the like, it is also a good method to provide the target value with a width ± h. If the detected data is equal to the target value, the process returns to step 1.

(First Embodiment) The basic flow of control is as shown in FIG. FIG. 3 shows a specific embodiment of subroutine 1 and subroutine 2 in FIG. 2. Steps 10401 to 10403 correspond to subroutine 1a and step 1110 corresponding to subroutine 1.
Subroutine 2a in which 1 to 11103 correspond to subroutine 2
It is.

If it is determined in step 3 that the pump discharge pressure H is smaller than the target pressure H0, the process proceeds to step 4. In step 4, the pump discharge pressure H in step 10402 of FIG.
Is set as the auxiliary target pressure H0 '. In step 5, the auxiliary target pressure H0 'is equal to the target pressure H0 value (or is the auxiliary target pressure H0' within the range of H0 having the width ± h), or in step 6 is the auxiliary target pressure H0.
If 0 'is greater than the target pressure H0, the value of the target pressure H0 is substituted for the auxiliary target pressure H0' in step 7. In step 8, the pump discharge pressure H is compared with the auxiliary target pressure H0 '.
In this case, the auxiliary target pressure H0 'may be compared with a width (± h). If they are equal (or if they are within the width H0 '± h), return to step 1. If they are not equal to each other, one bit (1 bit is a predetermined unit of increase / decrease of the pump speed) is added to the pump speed N in step 9 and the pump discharge pressure H is detected after elapse of Δt in step 10, and
And the process is repeated until the pump discharge pressure H becomes equal to the auxiliary target pressure H0 '. Here, step 10 is the integration time Δ
This is for allowing t to elapse. A method that allows this time to be changed to an appropriate value by an external setting, a learning function, or the like is also a good method. When the pump discharge pressure H becomes equal to the auxiliary target pressure H0 'in step 8, the process returns to step 1, and this is repeated to suppress hunting.

If the pump discharge pressure H is higher than the target pressure H0 in step 3, the process proceeds to step 11. Step 11
Then, in step 11102 of FIG. 3, a pressure obtained by subtracting the pressure value α previously stored in the memory of the microcomputer from the pump discharge pressure H is set as the auxiliary target pressure H0 '. After step 11, hunting is suppressed by performing control reverse to that of step 4 and thereafter. That is, while control is performed to increase the rotation speed after step 4, control is performed to reduce the rotation speed after step 11;
As described below, similar control can be performed in consideration of each code.

FIG. 11 is an example of an operation time chart of the first embodiment. The solid line is for the method according to the present invention, and the dotted line is for the conventional method. According to the method according to the present invention, it can be seen that hunting is significantly reduced as compared with the conventional method.

Embodiment 2 The basic flow of control is as shown in FIG. Another auxiliary target pressure setting method for preventing hunting will be described. Steps 1 to 3 are the same as in the first embodiment. FIG. 4 shows a specific embodiment of subroutine 1 and subroutine 2 in FIG.
0403 is a subroutine 1b corresponding to the subroutine 1, and steps 21101 to 21103 are a subroutine 2b corresponding to the subroutine 2.

If the pump discharge pressure H is smaller than the target pressure H0 in step 3, the process proceeds to step 4. In step 4, the auxiliary target pressure H0 'is set to a value obtained by adding 1/2 of the difference between the target pressure H0 and the pump discharge pressure H to the discharge pressure H in step 20402 in FIG. That is, H0 '= H + (H0-H) / 2 (Equation 4) is calculated to set the auxiliary target pressure H0'.

Steps 5 to 10 are the same as in the first embodiment.

If it is determined in step 3 that the pump discharge pressure H is equal to or higher than the target pressure H0, the process proceeds to step 11. Step 11
Thereafter, the control reverse to that of step 4 and thereafter is performed. That is, in step 11, the calculation of H0 '= H- (H-H0) / 2 (Equation 5) is performed in step 21102 of FIG. 4 to set the auxiliary target pressure H0'.

Steps 12 to 17 are performed in the first embodiment.
Is the same as

However, 1/2 in (Equation 4) and (Equation 5) can be an arbitrary numerical value, and is not necessarily limited to 1/2.

FIG. 12 is an example of an operation time chart of the second embodiment. The solid line is for the method according to the present invention, and the dotted line is for the conventional method. As can be seen from the above, according to the method of the present invention, hunting can be suppressed to be smaller than that of the conventional method.

(Embodiment 3) The basic flow of control is as shown in FIG. If the pump discharge pressure H is smaller than the target pressure H0 in step 3, the process proceeds to step 4. FIG. 5 shows Step 4 in FIG.
1 shows a specific embodiment of the subroutine 1 (subroutine 1c). Step 4 is the step shown in FIG.
If the discharge pressure H is larger than the preset value h1 in 30402, the target pressure H0 is set to the auxiliary target pressure H0 'in step 30403.
Set.

If it is determined in step 30402 that H.ltoreq.h1, and if it is determined in step 30404 that the pump discharge pressure H is greater than a predetermined value h2, the process proceeds to step 30405, where the discharge pressure H is set to the target pressure H0 and the pump discharge pressure. 1 / n of difference of H
Is set as the auxiliary target pressure H0 '.
That is, H0 '= H + (H0-H) / n (Equation 6) is calculated to set the auxiliary target pressure H0'.

If it is determined in step 30404 that H ≦ h2,
Proceed to step 30406 and execute similarly. When it is determined that the pump discharge pressure H is larger than the predetermined value hm when the processing is sequentially executed and the process proceeds to step 30407, the discharge pressure H is set to 1 / n of the difference between the target pressure H0 and H in step 30408.
Is set as the auxiliary target pressure H0 '. That is, H0 '= H + (H0-H) / n (Equation 7) is calculated to set the auxiliary target pressure H0'.

If it is determined in step 30407 that H ≦ hm, an auxiliary target pressure H0 'is set in step 30409 to a pressure obtained by adding 1 / n of the difference between the target pressure H0 and H to the discharge pressure H. That is, H0 '= H + (H0-H) / n (Equation 8) is calculated to set the auxiliary target pressure H0'.

However, h1> h2>...> Hmm = 1,2,3... N is an arbitrary positive number.

Steps 5 to 10 are the same as in the first embodiment.

If it is determined in step 3 that the pump discharge pressure H is equal to or higher than the target pressure H0, the process proceeds to step 11. FIG. 6 shows a specific example of subroutine 2 of step 11 in FIG. 2 (subroutine 2c). Step 11
Thereafter, the control reverse to that of step 4 and thereafter is performed.

In step 11, if the discharge pressure H is smaller than the preset value h1 'in step 31102 of FIG. 6, the target pressure H0 is set to the auxiliary target pressure H0' in step 31103.

In step 31102, it is determined that H≥h1 ', and in step 31104, the pump discharge pressure H is set to a predetermined value h.
If it is determined to be smaller than 2 ', the process proceeds to step 31105,
A value obtained by subtracting 1 / n of the difference between H and the target pressure H0 from the discharge pressure H is set as the auxiliary target pressure H0 '. That is, H0 '= H- (H-H0) / n (Equation 9) is calculated to set the auxiliary target pressure H0'.

If it is determined in step 31104 that H≥h2 ', the flow advances to step 31106 to execute the same operation. When it is determined that the pump discharge pressure H is smaller than a predetermined value hm 'when the processing is sequentially executed and the process proceeds to step 31107, the discharge pressure H is set to the auxiliary target pressure H0' in step 31108.
Is subtracted from 1 / n of the difference between H and the target pressure H0. That is, H0 '= H- (H-H0) / n (Equation 10) is calculated to set the auxiliary target pressure H0'.

If it is determined in step 31107 that H ≧ hm ′, a value obtained by subtracting 1 / n of the difference between H and the target pressure H0 from the discharge pressure H is set to the auxiliary target pressure H0 ′ in step 31109. I do. That is, H0 '= H- (H-H0) / n (Equation 11) is calculated to set the auxiliary target pressure H0'.

However, h1 '<h2' <... <Hm '.

Steps 12 to 17 are performed in the first embodiment.
Is the same as

Here, the width of decrease of h1 → h2 →... → hm and the increase of h1 ′ → h2 ′ →.
The value of m is also any positive integer. The value of n is an arbitrary positive number. For example, the value of n in (Equation 6) to (Equation 8),
The value of n in (Equation 9) to (Equation 11) may be different for each setting of the auxiliary target value H0 ', and the combination and numerical value are arbitrary.

FIG. 13 is an example of an operation time chart of the third embodiment. The solid line is for the method according to the present invention, and the dotted line is for the conventional method. According to the system according to the present invention, hunting can be suppressed to be smaller than in the conventional system.

(Embodiment 4) The basic flow of control is shown in FIG.
As shown in FIG.

If it is determined in step 3 that the pump discharge pressure H is smaller than the target pressure H0, the process proceeds to step 4. FIG. 7 shows a specific example of the subroutine 1 of step 4 in FIG. 2 (subroutine 1d). In step 4, the discharge pressure H is increased to the target pressure H0 in step 40402 in FIG.
If it is larger than the value obtained by subtracting the pressure value α previously stored in the memory of the microcomputer from the above, the target pressure H0 is set to the auxiliary target pressure H0 'in step 40403. That is, H0 '= H0 (Equation 12).

At step 40402, it is determined that H ≦ H0−α,
And if it is determined in step 40404 that H> H0-2α,
Proceeding to step 40405, a value obtained by subtracting α from the target pressure H0 is set as H0 '. That is, H0 '= H0-α (Equation 13) is calculated, and the auxiliary target pressure H0' is set.

If it is determined in step 40404 that H ≦ H0−2α, the process proceeds to step 40406 and is executed in the same manner. When the processing is sequentially executed and the process proceeds to step 40407, H> H0−mα
If it is determined in step 40408 that the target pressure H0 is less than the value obtained by multiplying α by (m-1), the auxiliary target pressure H
Set as 0 '. That is, H0 '= H0- (m-1) α (Equation 14) is calculated to set the auxiliary target pressure H0'.

If it is determined in step 40407 that H ≦ H0−mα, a value obtained by subtracting a value obtained by multiplying α by m from the target pressure H0 is set in step 40409 as the auxiliary target pressure H0 ′.
That is, H0 '= H0-mα (Equation 15) is calculated to set the auxiliary target pressure H0'.

Here, m = 1, 2, 3,....

Steps 5 to 10 are the same as in the first embodiment.

If the pump discharge pressure H is equal to or higher than the target pressure H0 in step 3, the process proceeds to step 11. FIG. 8 shows a specific embodiment of subroutine 2 of step 11 in FIG. 2 (subroutine 2d). Step 1
The control after step 1 is the reverse of the control after step 4.

In step 11, if the discharge pressure H is smaller than the target pressure H0 plus the pressure value α previously stored in the memory of the microcomputer in step 41102 in FIG. The target pressure H0 is set to the auxiliary target pressure H0 '. That is, H0 '= H0 (Equation 16).

At step 41102, it is determined that H ≧ H0 + α,
If it is determined in step 41104 that H <H0 + 2α,
In step 41105, a value obtained by adding α to the target pressure H0 is set as the target pressure H0 '. That is, H0 '= H0 + α (Equation 17) is calculated to set the auxiliary target pressure H0'.

If it is determined in step 41104 that H ≧ H0 + 2α, the flow advances to step 41106 to execute the same operation. When the processing is sequentially executed and the process proceeds to step 41107, H ≧ H0
If it is determined to be + mα, in step 41108, a value obtained by adding a value obtained by multiplying α by (m−1) to the target pressure H0 is set as the auxiliary target pressure H0 ′. That is, H0 '= H0 + (m-1) α (Equation 18) is calculated to set the auxiliary target pressure H0'.

If it is determined in step 41107 that H ≧ H0 + mα, in step 41109, H0 ′ = H0 + mα (Equation 19) is calculated to set the auxiliary target pressure H0 ′.

Here, m = 1, 2, 3,....

Steps 5 to 10 are the same as in the first embodiment.

As described above, in this embodiment, the interval between the discharge pressure H and the target pressure H0 is divided by the constant pressure α, and the closest to the target pressure H0 among the pressures dividing the auxiliary target pressure H0 '. This is set to a value, and this is repeated to stabilize at the true target pressure.

FIG. 14 is an example of an operation time chart of the fourth embodiment. The solid line is for the method according to the present invention, and the dotted line is for the conventional method. According to the method of the present invention, hunting can be suppressed to a small level.

(Embodiment 5) The basic flow of control is as shown in FIG.

If the pump discharge pressure H is smaller than the target pressure H0 in step 3, the process proceeds to step 4. FIG. 9 shows a specific example of subroutine 1 of step 4 in FIG. 2 (subroutine 1e). In step 4, the discharge pressure H is set to a predetermined value hm in step 50402 of FIG.
If it is smaller than, the auxiliary target pressure H0 'is set to hm in step 50403. That is, H0 '= hm (Equation 20).

In step 50402, it is determined that H ≧ hm, and in step 50404, the pump discharge pressure H is set to a predetermined value hm-1.
If it is determined to be smaller, the process proceeds to step 50405 and hm
-1 is set as the auxiliary target pressure H0 '. That is, H0 '= hm-1 (Equation 21) is calculated to set the auxiliary target pressure H0'.

If it is determined in step 50404 that H≥hm-1, the flow advances to step 50406, and the same is executed. When it is determined that the pump discharge pressure H is smaller than a predetermined value h1 when the process is sequentially executed and the process proceeds to step 50407,
In step 40408, h1 is set as the auxiliary target pressure H0 '. That is, H0 '= h1 (Equation 22) is calculated to set the auxiliary target pressure H0'.

If it is determined in step 50407 that H≥h1, in step 50409, the target pressure H0 is set as the auxiliary target pressure H0 '.

That is, H0 '= H0 (Equation 23). Here, m = 1, 2, 3,....

Steps 5 to 10 are the same as in the first embodiment.

If the pump discharge pressure H is equal to or higher than the target pressure H0 in step 3, the process proceeds to step 11. FIG. 10 shows FIG.
9 shows a specific example of the subroutine 2 of step 11 in (1) (subroutine 2e). The control after step 11 is the reverse of the control after step 4.

In step 11, step 51102 in FIG.
If the discharge pressure H is larger than the predetermined value hm 'in step 51103, the auxiliary target pressure H0' is set to hm 'in step 51103. That is, H0 '= hm' (Equation 24).

In step 51102, it is determined that H≤hm ', and in step 51104, the pump discharge pressure H is set to a predetermined value hm.
If it is determined that it is larger than -1 ', the routine proceeds to step 51105, where hm-1' is set as the auxiliary target pressure H0 '. That is, H0 '= hm-1' (Equation 25) is calculated to set the auxiliary target pressure H0 '.

If it is determined in step 51104 that H≤hm-1 ', the flow advances to step 51106 to execute the same operation. When it is determined that the pump discharge pressure H is larger than the predetermined value h1 'when the process is sequentially executed and the process proceeds to step 41107,
In step 51108, h1 'is set as the auxiliary target pressure H0'. That is, H0 '= h1' (Equation 26).

If it is determined in step 51107 that H ≦ h1 ′, the target pressure H0 is reduced to the auxiliary target pressure H0 ′ in step 51109.
Set as That is, H0 '= H0 (Equation 27). Here, m = 1, 2, 3,....

Steps 5 to 10 are the same as in the first embodiment.

As described above, in this embodiment, the discharge pressure H and the target pressure H0 are divided by an arbitrary pressure in advance, and the auxiliary target pressure is set to a pressure closest to the target pressure. The setting of the auxiliary target pressure H0 'can be performed, for example, between the discharge pressure H and the target pressure H0 based on Table 1 below.

[0069]

[Table 1]

Table 1 is for setting an auxiliary target pressure H0 'corresponding to the detected discharge pressure H. That is, the discharge pressure H
And target pressure H0 between 0.0 and Δh1, Δh as shown in Table 1.
1 to Δh2,..., Δhm to Δhn,.
Δh13, Δh13 to Δh14,..., And auxiliary target pressures h01, h11,.
.., H0,... Are stored in a memory in advance, and an auxiliary target pressure H0 ′ corresponding to the detected discharge pressure H is set. However, Δh1, Δh2,..., Δhm, Δ
hn,..., Δh12, Δh13, Δh14,... represent the pressure difference from the discharge pressure H. Δh1 <Δh2 <
... <Δhm <Δhn <... <Δh12 <Δh13 <Δ
h14 <..., but the increment intervals of each may not be constant.

FIG. 15 is an example of an operation time chart of the fifth embodiment. The solid line is for the method according to the present invention, and the dotted line is for the conventional method. According to the method of the present invention, hunting can be kept small.

Although the first to fifth embodiments have been described above, a method of setting the auxiliary target pressure H0 'by combining the embodiments according to the situation is also conceivable. Also, a method of automatically setting an appropriate value by a learning function when setting the auxiliary target pressure is conceivable. The present invention can be applied not only to the discharge pressure constant control but also to the terminal pressure constant control.

Although the auxiliary target value is controlled so as to approach the control target value discontinuously, it may be controlled so as to continuously and gradually approach the control target value.

In the above embodiment, the method of detecting and controlling the discharge pressure has been described. However, the control can be similarly performed by detecting the flow rate and the flow velocity.

[0075]

As described above, according to the first and second aspects, even if the difference between the actual pump discharge pressure and the preset discharge pressure target value is large, hunting occurs. Thus, a liquid supply device capable of driving a pump and a control method thereof are obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a configuration diagram of a liquid supply device according to the present invention.

FIG. 2 is a diagram showing an embodiment of an overall flowchart showing an operation procedure according to the present invention.

FIG. 3 is a diagram showing a first embodiment of a flowchart showing an operation procedure according to the present invention.

FIG. 4 is a flowchart showing a second embodiment of a flowchart showing an operation procedure according to the present invention.

FIG. 5 is a view showing a third embodiment of the flowchart showing the operation procedure according to the present invention.

FIG. 6 is a view showing a third embodiment of the flowchart showing the operation procedure according to the present invention.

FIG. 7 is a view showing a fourth embodiment of the flowchart showing the operation procedure according to the present invention.

FIG. 8 is a view showing a fourth embodiment of the flowchart showing the operation procedure according to the present invention.

FIG. 9 is a view showing a fifth embodiment of the flowchart showing the operation procedure according to the present invention.

FIG. 10 is a view showing a fifth embodiment of the flowchart showing the operation procedure according to the present invention.

FIG. 11 is an explanatory diagram of the operation of the first embodiment according to the present invention.

FIG. 12 is a diagram illustrating the operation of the second embodiment according to the present invention.

FIG. 13 is an explanatory diagram of the operation of the third embodiment according to the present invention.

FIG. 14 is an explanatory diagram of the operation of the fourth embodiment according to the present invention.

FIG. 15 is an explanatory diagram of the operation of the fifth embodiment according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Liquid supply device, 2 ... Pump, 3 ... Pump drive device, 4 ...
Control amount data detecting means, 5 ... Control panel.

Claims (2)

(57) [Claims] A pump and a pump drive for driving the pump
And operated device, a discharge pressure detection <br/> detecting means for detecting a delivery pressure of the pump, a preset with the output of said discharge pressure detection means
Pump drive device so that the discharge pressure target value
In the liquid supply device comprising a control means for controlling the location changing the rotational speed of the pump, auxiliary target in accordance with the output of said discharge pressure detection means between said discharge pressure target value and the output of said discharge pressure detection means The value
The output of the discharge pressure detecting means and the auxiliary
When the deviation from the target value becomes equal to or less than a predetermined value, the discharge pressure
When the difference between the target value and the discharge pressure of the pump is equal to or greater than a predetermined value.
The output of the discharge pressure detecting means and the discharge pressure
A new value corresponding to the output of the discharge pressure detecting means between the standard value
The auxiliary target value is gradually increased by providing
Auxiliary target value setting means for approaching the discharge pressure target value,
The output of the discharge pressure detecting means matches the auxiliary target value.
Liquid supply apparatus characterized by comprising a means for controlling such that. 2. A pump having a pump, and a discharge pressure of the pump is controlled.
Control to match the set discharge pressure target value.
In the control method of the liquid supply device, the deviation between the actual discharge pressure of the pump and the discharge pressure target value is determined.
Between the discharge pressure target value and the discharge pressure in accordance with
A first step of setting an auxiliary target value;
Second step of controlling the pump discharge pressure so that
And the deviation between the pump discharge pressure and the auxiliary target value
When the pressure falls below a certain value, the discharge pressure of the pump and the discharge
When the difference from the pressure target value is equal to or more than a predetermined value, the first step is performed.
And a step of repeating the second step.
And a control method of the liquid supply device .