JPH07172155A - D.c. voltage detecting device and drive control device for electric compressor of automobile using it - Google Patents

Abstract

PURPOSE:To prevent a motor for an electric compressor from stopping and greatly changing its number of revolutions due to an overload and a magnetic overexcitation thereof even if a power supply voltage is greatly changed according to the state of the running of an automobile by cheaply insulating a high voltage system from a low voltage system, keeping a small size, a light weight and spacing saving, decreasing a manufacture cost; and simplifying administration of parts. CONSTITUTION:A D.C. voltage detecting means 10 is provided, by comprising D.C. voltage generating means 1 for generating a D.C. voltage, an electric compressor 9 endosing a motor driven by electrical input a D.C./A.C. conversion means 8 for converting the D.C. voltage to a simulated A.C. voltage in its state of plus and minus pulse line, a window.comparator circuit 4 for making a first voltage obtained by dividing the DC voltage by a resistance as one side input, and making a standard voltage as other input; and insulating means 5 for insulating an output of the window.comparator circuit 4 from the D.C. voltage generating means 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for an electric compressor for an automobile equipped with the electric compressor.

[0002]

2. Description of the Related Art A voltage detecting means of a conventional drive control device for an electric compressor for an automobile will be described with reference to the drawings.

Generally, there are the following methods as means for detecting voltage. That is, as shown in FIGS. 5 and 6, the DC voltage is applied to the first resistor 2 and the second resistor 14.
There are a method of detecting the voltage by dividing the voltage with and a method of detecting using the transformer 15 as shown in FIG. In FIG. 5, the divided DC voltage is detected linearly, and in FIG. 6, the divided DC voltage is compared with the threshold value of the window comparator circuit to detect the DC voltage in an arbitrary range. .

In FIG. 7, the DC voltage is detected according to the turns ratio of the primary winding and the secondary winding of the transformer.

Further, Japanese Patent Publication No. 5-35993 and
In Japanese Unexamined Patent Publication No. 5-139150, voltage detection means,
It does not mention the control of the electric compressor and the contents of the driving means associated with the fluctuation of the power supply voltage.

[0006]

However, in the configuration in which the direct current voltage is divided by the resistance as described above and the configuration in which the divided voltage is compared with the threshold value of the window comparator circuit, the electric compressor is used. Since there is no insulation between the high voltage system including the drive power supply and the low voltage system including the control power supply, there is a danger that the operator may get an electric shock. There is a problem that the detection means is expensive and becomes large.

Further, for example, in FIG. 6, when the power supply voltage is different, the first resistor 2 and the second resistor 14 which detect the first voltage when it is necessary to detect the voltage proportional to the power supply voltage. If the value of is fixed, the value of the resistor that sets the reference voltage that is one input of the window comparator circuit must be set according to each power supply voltage,
Conversely, when the value of the resistor that sets the reference voltage is fixed, the first resistor 2 and the second resistor 14 that detect the first voltage are used.
The value of must be set according to each power supply voltage. Therefore, no matter which input side of the window / comparator circuit is fixed, at the time of manufacturing, it is necessary to have a component corresponding to each power supply voltage, which hinders reduction of manufacturing cost and takes time for component management. Had a problem.

Further, the power supply voltage of an automobile fluctuates much more than a household commercial power supply. For example, in the case of an electric vehicle, a large load current flows through a running motor when the vehicle accelerates, so that the power supply voltage drops. When the speed is reduced, the power supply voltage rises due to the regenerative current from the traveling motor. Therefore, the applied voltage of the electric compressor also fluctuates greatly depending on the running condition of the vehicle.As a result, when the electric compressor motor is an induction motor, it is overloaded when the power supply voltage drops and overexcited when the power supply voltage rises. This has caused an increase in current and a decrease in motor efficiency. In addition, when the motor of the electric compressor is a DC brushless motor, there is a problem that the rotation speed decreases when the power supply voltage decreases and the rotation speed increases when the power supply voltage increases, and the rotation speed of the compressor fluctuates greatly.

The present invention solves the above-mentioned problems of the prior art, insulates a high-voltage system and a low-voltage system from each other to prevent electric shock, is inexpensive, small-sized and lightweight, reduces the manufacturing cost, and manages parts. Even if the power supply voltage fluctuates depending on the running state of the vehicle, the motor of the electric compressor may be overloaded or over-excited to increase the motor current, reduce the motor efficiency, or change the rotation speed. It is intended to supply a drive control device for an electric compressor for an automobile which is not provided.

[0010]

In order to solve the above-mentioned problems, the present invention provides (1) a DC voltage generating means for generating a DC voltage, an electric compressor having a motor driven by an electric input, and the DC voltage. A DC / AC converting means for converting a voltage into a positive / negative pulse train-like pseudo AC voltage, and a window in which the first voltage obtained by dividing the DC voltage with a resistor is used as one input and the reference voltage is used as the other input. A DC voltage detecting means having a comparator circuit and an insulating means for insulating the output of the window / comparator circuit from the DC voltage generating means is provided.

(2) DC voltage generating means for generating a DC voltage, an electric compressor incorporating a motor driven by an electric input, and a DC / AC converting means for converting the DC voltage into a positive / negative pulse train pseudo AC voltage. And a window comparator circuit having a first voltage obtained by dividing the DC voltage using at least one variable resistor as one input and a reference voltage as the other input, and an output of the window comparator circuit. A DC voltage detecting means having an insulating means for insulating from the DC voltage generating means is provided.

(3) DC voltage generating means for generating a DC voltage, an electric compressor having a motor driven by an electric input, and a DC / AC converting means for converting the DC voltage into a pseudo AC voltage in the form of positive and negative pulse trains. And a window comparator circuit in which a first voltage obtained by dividing the DC voltage by a resistor is used as one input and a reference voltage is used as the other input, and the output of the window comparator circuit is used as the DC voltage generating means. And a pulse width changing means for changing the individual pulse width of the pulse train according to the DC voltage detected by the DC voltage detecting means. is there.

[0013]

According to the present invention, with the above-described structure, the high voltage system and the low voltage system can be inexpensively manufactured without using the transformer by the DC voltage detecting means in which the output of the window comparator circuit is connected to the insulating means, for example, the photo coupler. Insulate
It can be small, lightweight and space-saving.

Further, by using at least one variable resistor as a resistor for dividing and detecting the DC voltage, when the power source voltage is different and it is necessary to detect a voltage proportional to the power source voltage, the variable resistor Since the value of the detected first voltage can be made uniform by adjusting the value, the circuit for setting the reference voltage can be shared, and the DC voltage detection means of the same circuit can be used. It is possible to reduce costs and simplify parts management.

Further, when the DC voltage is converted into the pseudo AC voltage in the form of a pulse train by the DC / AC converting means, the individual pulses of the pulse train are changed by the pulse width changing means in accordance with the DC voltage detected by the DC voltage detecting means. By changing the width and making the effective voltage of the pseudo AC voltage constant, even if the power supply voltage fluctuates greatly depending on the running condition of the vehicle, the motor of the electric compressor is overloaded or overexcited, and the rotation speed is It is possible to prevent large fluctuations.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A drive control device for an electric compressor for a vehicle according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing an embodiment of a DC voltage detecting means of a drive control device for an automobile electric compressor according to the present invention.

FIG. 2A is a comparison table of the power supply voltage VDC and the resistance values of the first resistor 2 and the variable resistor 3, and FIG.
4 is a comparison table of the fluctuation rate of the power supply voltage VDC and the first voltage V1 detected with respect to the fluctuation of the power supply voltage VDC.

An embodiment of the DC voltage detection of the present invention will be described below for the case where the power supply voltage VDC is DC100V and DC200V.

As shown in FIG. 2A, the value of the first resistor 2 is 171 KΩ and the variable resistor 3 is independent of the power supply voltage.
If only the values of 19 KΩ and 9 KΩ are set according to the power supply voltage, the detected first voltage V1 depends only on the fluctuation rate of the power supply voltage. The voltage value of is detected. Therefore, even if the power supply voltage is different, the other window comparator circuits can be shared by adjusting the variable resistance.

FIG. 3 is an embodiment of a system diagram using the DC voltage detecting means 10. In accordance with the voltage of the DC voltage generating means 1 detected by the DC voltage detecting means 10, the pulse width output to the DC / AC converting means 8 is adjusted by the pulse width changing means 12.

FIG. 4 is a line voltage diagram showing how the line voltage of the three-phase pseudo AC waveform applied to the electric compressor 9 changes when the DC voltage changes at the same output frequency. Hereinafter, the operation of the drive control device for the electric compressor 9 for an automobile according to one embodiment of the present invention will be described.
A case where the nominal voltage is DC200V will be described. Figure 4
(A) shows that the actual DC voltage VDC is equal to the nominal voltage D
It is a line voltage diagram at C200V. In this case, t1, t
The output pulse widths of 2, t3, t4, and t5 are equal to the basic pulse width data in the ROM 13, and the electric compressor 9
The effective value VAC of the line voltage applied to is 100V. FIG. 4B is a line voltage diagram when the DC voltage VDC actually detected by the DC voltage detection means 10 is 400V. In this case, if the pulse width is the same as the basic data of the ROM 13, the effective value VAC of the line voltage is 200.
However, the output pulse width is (1/2) t1, (1 /
2) t2, (1/2) t3, (1/2) t4, (1 /
2) Since t5 and basic pulse width data are multiplied by (1/2), the effective value VAC of the line voltage applied to the electric compressor 9 does not change from 100V.
FIG. 4C is a line voltage diagram when the DC voltage VDC actually detected by the DC voltage detection means 10 is 160V. In this case, the output pulse width is (5/4) t1, (5
/ 4) t2, (5/4) t3, (5/4) t4, (5 /
4) Since t5 and the basic pulse width data are multiplied by (5/4), the execution value VAC of the line voltage applied to the electric compressor 9 does not change to 100V.

[0023]

As is apparent from the above description, the present invention has the following advantages.
DC voltage generating means for generating a DC voltage, an electric compressor containing a motor driven by an electric input, a DC / AC converting means for converting the DC voltage into a positive / negative pulse train pseudo AC voltage, and the DC voltage A window comparator circuit having a first voltage divided by a resistor as one input and a reference voltage as the other input, and an insulation for insulating the output of the window comparator circuit from the DC voltage generating means. By providing the DC voltage detecting means having the means, it is possible to inexpensively insulate the high-voltage system and the low-voltage system from each other, and to reduce the size, the weight, and the space.

Further, a DC voltage generating means for generating a DC voltage, an electric compressor incorporating a motor driven by an electric input, and a DC / AC converting means for converting the DC voltage into a positive / negative pulse train pseudo AC voltage. , A window comparator circuit having a first voltage obtained by dividing the DC voltage using at least one variable resistor as one input and a reference voltage as the other input, and an output of the window comparator circuit By providing the DC voltage detecting means having the insulating means for insulating from the DC voltage generating means, it is possible to use the DC voltage detecting means of the same circuit even if the specifications of the power supply voltage are different. Management can be simplified.

Further, a DC voltage generating means for generating a DC voltage, an electric compressor incorporating a motor driven by an electric input, and a DC / AC converting means for converting the DC voltage into a positive / negative pulse train-like pseudo AC voltage. , A window comparator circuit having a first voltage obtained by dividing the DC voltage by a resistor as one input and a reference voltage as the other input, and an output of the window comparator circuit from the DC voltage generating means. By having a DC voltage detecting means having an insulating means for insulation and a pulse width changing means for changing each pulse width of the pulse train in accordance with the DC voltage detected by the DC voltage detecting means, Even if the power supply voltage fluctuates greatly depending on the running state of the electric compressor, the motor of the electric compressor is overloaded or overexcited It is possible to prevent the greatly fluctuates.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a DC voltage detecting means according to an embodiment of the present invention.

FIG. 2A is an explanatory diagram showing a comparison between the power supply voltage VDC and the resistance values of the first resistance and the variable resistance. FIG. 2B is a diagram showing a fluctuation rate of the power supply voltage VDC and a fluctuation of the power supply voltage VDC. Explanatory diagram showing comparison with the first voltage V1

FIG. 3 is a configuration diagram of an embodiment of the present invention.

FIG. 4 is a line voltage waveform diagram according to an embodiment of the present invention.

FIG. 5 is a circuit diagram of a voltage detecting means of a conventional example.

FIG. 6 is a circuit diagram of a voltage detecting means of a conventional example.

FIG. 7 is a circuit diagram of a voltage detecting means of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DC voltage generating means 2 1st resistance 3 Variable resistance 4 Window comparator 5 Insulating means 6 Vehicle running motor 7 Switching element 8 DC / AC converting means 9 Electric compressor 10 DC voltage detecting means 11 Switching element control signal generating section 12 Pulse Width changing means 13 ROM 14 Second resistance 15 Transformer

Claims (3)

[Claims] 1. A DC voltage generating means for generating a DC voltage,
An electric compressor having a built-in motor driven by an electric input, a DC / AC converting means for converting the DC voltage into a positive / negative pulse train-like pseudo AC voltage, and a first voltage obtained by dividing the DC voltage by a resistor. A DC voltage detecting device having a window comparator circuit having one input and a reference voltage as the other input, and an insulating means for insulating the output of the window comparator circuit from the DC voltage generating means. 2. A DC voltage generating means for generating a DC voltage,
An electric compressor having a built-in motor driven by an electric input, a DC / AC conversion unit for converting the DC voltage into a pseudo AC voltage in the form of positive and negative pulse trains, and the DC voltage is divided using at least one variable resistor. A DC voltage having a window comparator circuit having the first voltage as one input and a reference voltage as the other input, and an insulating means for insulating the output of the window comparator circuit from the DC voltage generating means. Detection device. 3. A DC voltage generating means for generating a DC voltage,
An electric compressor having a built-in motor driven by an electric input, a DC / AC converting means for converting the DC voltage into a positive / negative pulse train-like pseudo AC voltage, and a first voltage obtained by dividing the DC voltage by a resistor. DC voltage detection means having one input and a window comparator circuit having a reference voltage as the other input, and an insulating means for insulating the output of the window comparator circuit from the DC voltage generating means, A drive control device for an electric compressor for an automobile, comprising pulse width changing means for changing each pulse width of the pulse train according to a DC voltage detected by a DC voltage detecting device.