JP2982400B2 - Control circuit of two-phase double chopper device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control circuit for a two-phase double chopper device in which two sets of chopper devices are connected in parallel and operated with a phase difference of 180 degrees from each other.

[0002]

2. Description of the Related Art FIG. 3 is a main circuit connection diagram showing a first conventional example of a two-phase double chopper device. In FIG. 3, the first chopper unit 11, the first reactor 12, and the first freewheel diode 13 which connect the transistor 11T and the diode 11D in anti-parallel form a first chopper device, and Similarly, the chopper device includes a second chopper unit 21, a second reactor 22, and a second freewheel diode 23 in which the transistor 21T and the diode 21D are connected in anti-parallel. A two-chopper device is connected in parallel to a common DC power supply 1, and a DC motor 2 as a load is commonly connected and driven. Here, the current supplied from each chopper device to the DC motor 2 is 5
A common duty command signal is applied to both chopper devices so that they are in increments of 0 percent, and their operation is
Operate to maintain a phase difference of 0 degrees.

As described above, the two-phase double chopper device is
In the case of operating with a phase difference of 80 degrees, when the flow rate exceeds 50%, there is a period in which both chopper devices are both on, so this is not shown in FIG. In order to control the switching operation of each of the first chopper section 11 and the second chopper section 21, it is necessary to provide a phase shift conversion circuit for each. However, when the control circuit of the chopper device is configured by an analog circuit, if there is an error between the adjustment of one phase-shift conversion circuit and the adjustment of the other phase-shift conversion circuit, these errors are caused by the respective conduction ratios. An error in the command signal results in an imbalance between the output currents of the two chopper devices. As a result, even if the difference between the duty ratio command signals is small at first, the output current of the chopper device with the larger duty ratio command signal flows back to the chopper device with the smaller duty ratio command signal. As a result, there is a disadvantage that the difference between the currents flowing through the two chopper devices becomes large. If there is a difference in characteristics between the main circuit elements, for example, the transistor 11T and the transistor 21T, this also causes an imbalance in current.

FIG. 4 is a main circuit connection diagram showing a second conventional example of a two-phase double chopper device. This second conventional example circuit
The first backflow prevention diode 14 is inserted on the power supply side of the first chopper section 11, and the second backflow prevention diode 24 is inserted on the power supply side of the second chopper section 21.
This is a point different from the conventional circuit.
DC motor 2 as load, first chopper section 11, first
Reactor 12, first freewheel diode 13,
The names, applications, and functions of the second chopper section 21, the second reactor 22, and the second freewheel diode 23 are the same as those of the first conventional circuit described above with reference to FIG.

[0005]

SUMMARY OF THE INVENTION FIG.
The first conventional circuit of the phase double chopper device has a problem that a current flows backward from one chopper device to the other chopper device due to the above-described cause, that is, a current imbalance occurs. As shown in the second conventional circuit, the first backflow prevention diode 14 and the second backflow prevention diode 24 are inserted into the power supply side of the first chopper section 11 and the power supply side of the second chopper section 21, respectively. Can be solved. However, during operation of the chopper device, a current always flows through these backflow prevention diodes to generate a loss, so that energy is wasted and the efficiency of the device is reduced. Further, the installation of the backflow prevention diode causes problems such as an increase in cost and an increase in the size of the device. If the phase shift converter is digitized using a microprocessor, the above-mentioned problem of the adjustment error of the phase shift converter can be solved. Therefore, the above-described backflow prevention diode does not need to be used. There are drawbacks that the system becomes complicated, software design requires a great deal of effort, and costs increase.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the current imbalance of a two-phase double chopper device without using a backflow prevention diode or digitizing a phase shift converter. It is in.

[0007]

In order to achieve the above object, a control circuit according to the present invention comprises a first chopper device connected to a DC power supply and outputting a DC having a voltage different from the DC power supply, and a second chopper device. The two choppers are connected in parallel to each other, a common duty ratio command signal is applied to both choppers, and their operation phases are shifted from each other by 180 degrees. Current detecting means for separately detecting a current, current deviation detecting means for detecting a deviation between the two detected currents, and a duty ratio correcting means for correcting the duty ratio command signal in accordance with the detected difference value; Although both chopper devices are provided separately, the current deviation is detected by the differential amplifying means, and the correction signal for making the current deviation zero is obtained from the proportional-integral adjusting means. Further, when the detected current deviation value is small or when the chopper device is stopped, the proportional integral adjusting means is switched to the proportional adjusting means.

[0008]

In a two-phase double chopper device in which two sets of chopper devices are operated in parallel, a duty ratio command signal generated due to a slight adjustment difference of the phase shift conversion circuit and a slight difference in characteristics of the main circuit elements. The difference between the two causes a large imbalance in the output currents of the two chopper devices. In the present invention, a deviation of the output currents of the two chopper devices is detected, and a control signal for making the current deviation detection value zero is provided. By adding the control signal so as to correct the duty ratio command signal given to each chopper device, it is possible to use a backflow prevention diode that generates power loss or increase the cost of the device. In order to eliminate the imbalance of the current output from the chopper device while avoiding the above, a current deviation is detected by differential amplification means, and a control signal for making this current deviation zero is proportionally integrated and adjusted. Removed from the stage, and corrects the duty ratio signal by the control signal. Further, when the current deviation detected by the differential amplifying means is small, or when the chopper device is stopped, the correction is not necessary. Therefore, short-circuit the integration capacitor of the proportional-integral adjusting means. Thus, by switching to a proportional adjustment operation with an extremely small gain, unnecessary correction operation is prevented from being performed.

[0009]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention. A DC power supply 1, a DC motor 2 as a load, a first chopper section 11, 1 reactor 12, 1st freewheel diode 13, 2nd
Since the names, applications, and functions of the chopper section 21, the second reactor 22, and the second freewheel diode 23 are the same as those of the first conventional circuit described above with reference to FIG. 3, the description thereof will be omitted.

In the circuit of the first embodiment, the output current of the first chopper device is detected by the first current detector 15, and the output current of the second chopper device is detected by the second current detector 25. The current is input to the current deviation detection circuit 3 to detect the deviation between the two currents,
The second duty ratio correction circuit 26 supplies the duty ratio correction circuit 16 with the polarity of the deviation detection value by the inverting amplifier 4.
And give to. Since a common duty command signal is input to the first duty correction circuit 16 and the second duty correction circuit 26, the duty detection signal is corrected by the above-described deviation detection value. . Therefore, the first duty ratio correction circuit 16 provides an operation signal having an appropriate duty ratio to the first chopper section 11, and at the same time, the second duty ratio correction circuit 26 also outputs an operation signal having an appropriate duty ratio to the second chopper portion 11.
Output to chopper section 21.

FIG. 2 is a circuit diagram showing a second embodiment of the present invention. A DC power supply 1, a DC motor 2 as a load, a first chopper section 11, and a first The names, applications, and functions of the reactor 12, the first freewheel diode 13, the second chopper section 21, the second reactor 22, and the second freewheel diode 23 are the same as those of the first conventional circuit described in FIG. Therefore, these descriptions are omitted.

In the circuit of the second embodiment, the output current of the first chopper device is detected by the first current detector 15, and the output current of the second chopper device is detected by the second current detector 25. This is the same as the case of the first embodiment. In the circuit of the second embodiment, the two detection currents are input to the differential amplifier 5, and the current deviation detected by the differential amplifier 5 is input to the proportional-integral controller 6, so that the proportional-integral controller 6 is A control signal for adjusting the input to zero will be output. Therefore, the first adder 17 adds the duty ratio command signal with the polarity corrected by the control signal from the proportional-plus-integral adjuster 6, and gives the addition result to the first phase-shift converter 18, whereby the first From the phase shift converter 18 to the first chopper 11
To the operating signal of the appropriate duty ratio. Since a control signal having a polarity opposite to that of the first adder 17 is supplied to the second adder 27, the control signal and the duty ratio command signal are added, and the addition result is used as a second phase shift converter. An operation signal having an appropriate duty ratio is output from 28 and this is input to the second chopper 21.

FIG. 5 is a circuit diagram showing a third embodiment of the present invention. A DC power supply 1, a DC motor 2 as a load, a first chopper section 11, and a first The names, applications, and functions of the reactor 12, the first freewheel diode 13, the second chopper unit 21, the second reactor 22, and the second freewheel diode 23 are those used in the first conventional circuit described above with reference to FIG. Is the same as The differential amplifier 5, the proportional-integral amplifier 6, the first adder 17, the first
The names, applications, and functions of the phase shift converter 18, the second adder 27, and the second phase shift converter 28 are the same as those used in the circuit of the second embodiment described above with reference to FIG. Therefore, their description is omitted.

In the circuit of the third embodiment, the output current of the first chopper device is detected by the first current detector 15, and the output current of the second chopper device is detected by the second current detector 25. This is the same as the case of the first embodiment. or,
Since the two detected currents are input to the differential amplifier 5 and the current deviation detected by the differential amplifier 5 is input to the proportional-integral controller 6, the proportional-integral controller 6 controls the input to zero. The first adder 17 adds the duty ratio command signal with the polarity corrected by the control signal from the proportional-plus-integral controller 6, and outputs the addition result to the first phase shift converter 18. Thus, an operation signal having an appropriate duty ratio is given from the first phase shift converter circuit 18 to the first chopper section 11 and, at the same time, the second adder 27 has the opposite polarity to the first adder 17 described above. Therefore, the control signal is added to the duty ratio command signal, and the addition result is output from the second phase shift converter 28 as an operation signal having an appropriate duty ratio, and is output.
This is input to the second chopper section 21 by the second
This is the same as the case of the circuit of the embodiment.

In the circuit of the third embodiment shown in FIG. 5, the output of the differential amplifier 5 is input to a comparator 33 via an absolute value calculator 31 where it is compared with a reference voltage 32. I have. That is, the absolute value of the output of the differential amplifier 5 is equal to the reference voltage 3
If the value is smaller than the set value V _{S of} 2, the comparison operator 33
Outputs a logical H signal to the OR gate 34. The OR gate 34 constituted by a logical sum element is further supplied with a logical L signal when the two-phase double chopper device is operating and a logical H signal when the two-phase double chopper device is stopped.
When 4 outputs a logic H signal, the short circuit switch 35 is turned on by the logic H signal. When the short-circuit switch 35 is turned on, the integration capacitor 6C of the proportional-integral controller 6 is short-circuited, and the operation of the proportional-integral controller 6 at this time becomes an operation as a proportional controller. If the gain at the time of this proportional adjustment operation is set to a sufficiently small value, the proportional-integral controller 6
Since the control signal for correcting the duty ratio command signal output by the controller has a very small value, it can be considered that the correction operation is substantially stopped. That is, when the two-phase double chopper device is stopped, or when the output of the differential amplifier 5 is small (that is, the current deviation value is small) even while the two-phase double chopper device is operating, the correction operation is substantially performed. It is in a stopped state. The correction operation is performed when the short-circuit switch 35 is off, that is, when the two-phase double chopper device is in operation and the current deviation value exhibits a certain value or more.

[0016]

In the two-phase double chopper device constituted by connecting two sets of chopper devices in parallel, a slight difference in the adjustment of the phase shift conversion circuit of each chopper device and the main circuit element of each chopper device. There is a problem that the output currents of the two chopper devices are largely different due to the slight difference in the characteristics of the two chopper devices. However, according to claim 1 or 2 of the present invention, the difference between the output currents of the two chopper devices is And a control signal for making the current deviation zero is obtained, and the control signal is used to correct the duty ratio command signal common to the two-phase double chopper device. That is, the control signal applied to the first chopper device and the control signal applied to the second chopper device are control signals having the same magnitude but different polarities. By adding this control signal to the duty ratio command signal separately for each chopper device, a new duty ratio command signal is obtained. By using this new duty ratio command signal, it is not necessary to use a backflow prevention diode that generates power loss, or without increasing the cost of the device due to digitization, so that the output current of the two-phase double chopper device can be reduced. However, according to the third aspect of the present invention, when the current detection error is small or when the chopper device is stopped, the duty ratio correction By switching the operation of the proportional-integral adjusting means for outputting the control signal to the proportional-adjusting operation having a small gain, it is possible to obtain an effect of avoiding the disadvantage that unnecessary correction operation is performed.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a main circuit connection diagram showing a first conventional example of a two-phase double chopper device.

FIG. 4 is a main circuit connection diagram showing a second conventional example of a two-phase double chopper device.

FIG. 5 is a circuit diagram showing a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DC power supply 2 DC motor as load 3 Current deviation detection circuit 4 Inverting amplifier 5 Differential amplifier 6 Proportional integration controller 6C Integrating capacitor 11 First chopper unit 12 First reactor 13 First freewheel diode 14 First reverse current prevention diode DESCRIPTION OF SYMBOLS 15 1st current detector 16 1st duty ratio correction circuit 17 1st adder 18 1st phase shift conversion circuit 21 2nd chopper part 22 2nd reactor 23 2nd freewheel diode 24 2nd backflow prevention diode 25 2nd Current detector 26 Second conduction ratio correction circuit 27 Second adder 28 Second phase shift conversion circuit 31 Overall value calculation circuit 32 Reference voltage 33 Comparison calculation unit 34 OR gate 35 Short circuit switch

Claims (3)

(57) [Claims] A first chopper device and a second chopper device which are connected to a DC power supply and output a DC having a different voltage from the DC power supply are connected in parallel, and a duty ratio command common to both the chopper devices is provided. In a two-phase double chopper device which operates while providing a signal and operating at 180 degrees out of phase with each other, current detecting means for separately detecting output currents of the two chopper devices, and detecting a deviation between the two detected currents A current deviation detecting means for detecting the deviation and a duty ratio correcting means for correcting the duty ratio command signal in accordance with the detected deviation value. Control circuit. 2. A first chopper device and a second chopper device which are connected to a DC power source and output a DC having a voltage different from that of the DC power source are connected in parallel, and a duty ratio command common to both the chopper devices is provided. In a two-phase double chopper device which operates while shifting its operation phase by 180 degrees with each other, a current detection means for separately detecting the output currents of the two chopper devices, A differential amplifying means for detecting a deviation between the two, a proportional-integral adjusting means for inputting the deviation detection signal and outputting a control signal for making the difference zero,
First adding means for adding the control signal to the duty ratio command signal with a polarity for correcting the duty ratio command signal;
A first phase shift converter for operating the first chopper device based on an addition result of the adding unit, and a control signal having a polarity opposite to that of the control signal input to the first adding unit and the conduction ratio command signal are added. A second adding means for operating the second chopper device based on the addition result of the second adding means.
A control circuit for a two-phase double chopper device, comprising: a phase shift converter. 3. A first chopper device and a second chopper device which are connected to a DC power source and output a DC having a different voltage from the DC power source are connected in parallel, and a duty ratio command common to both the chopper devices is provided. In a two-phase double chopper device which operates while shifting its operation phase by 180 degrees with each other, a current detection means for separately detecting the output currents of the two chopper devices, A differential amplifying means for detecting a deviation between the two, a proportional-integral adjusting means for inputting the deviation detection signal and outputting a control signal for making the difference zero,
A short-circuit switch for short-circuiting the integration capacitor of the proportional-integral adjusting means; a comparison operation means for detecting whether an absolute value of a deviation detection signal output by the differential amplifying means is within a predetermined value; A logic gate for turning on the short-circuit switch when the absolute value is within a predetermined value or when the two-phase double chopper device is stopped, and a control signal output from the proportional-integral adjusting means, First addition means for adding the duty ratio command signal to the signal with a polarity for correcting the signal, first phase shift conversion means for operating the first chopper device based on the addition result of the first addition means, and first addition means Second adding means for adding a control signal having a polarity opposite to that of the control signal input to the means and the duty ratio command signal; and a second operating the second chopper device based on the addition result of the second adding means. Transfer The control circuit of the 2-phase double chopper apparatus characterized by comprising a conversion means.