JPH08191571A - Inverter device - Google Patents

Abstract

PURPOSE: To provide an inverter device for stabilizing the operation of a chopper circuit owing to the fluctuation of a DC power supply voltage in the inverter device for applying a DC power supply to an inverter circuit in a chopper circuit with a switching circuit using an intelligent power module(IPM) and for continuing the inverter operation. CONSTITUTION: In an IPM 61 where a switching element 63 and a control circuit 64 are packaged and a power supply circuit 62 are used for a switching circuit of a chopper circuit C for stabilizing the voltage of a DC power supply and an inverter device for applying an AC voltage V3 to a load A by operating an inverter circuit B with an output DC voltage V2 of the chopper circuit C, a DC voltage V4 generated by rectifying the output AC voltage V3 of the inverter circuit B via a transformer 80 and a rectification circuit 81 is supplied to the control circuit 64 of the IPM 61 as a power supply energy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device in which a chopper circuit and an inverter circuit are formed by using an intelligent power module having a switching element and a control circuit thereof as a switching circuit element.
The present invention relates to a power supply circuit that supplies a control power supply voltage to an intelligent power module in a chopper circuit.

[0002]

2. Description of the Related Art A single-phase full-bridge inverter circuit shown in FIG. 4 will be described as an example of using an intelligent power module. This single-phase full-bridge inverter circuit has four intelligent power modules [hereinafter simply referred to as IPM] for the inverter DC power supply 1.
2 to 5 are connected in a full bridge configuration. Each IPM2
5 to 5, switching elements [IGBT] 6 to 9 in which diodes are connected in parallel, and control circuits 10 to 13 for controlling the switching elements 6 to 9 form a main part. Each of the IPMs 2 to 5 is a commercially available product packaged with various functions such as overcurrent protection, short-circuit current protection, overheat protection and control power supply voltage drop protection.

Incidentally, in FIG. 4, 14 to 17 are respective IPMs.
2 to 5 drive circuits connected to the front stages of the control circuits 10 to 13, 18 to 21 are electrolytic capacitors connected in parallel to the front stages of the drive gate circuits 14 to 17, and 22 to 25 are electrolytic capacitors 18 to 21. , A control circuit power transformer connected to the front stage of each of the rectifying circuits 22 to 25, an AC power source for IPM control, and 31 and 32 output AC to the load A. This is the output terminal to apply.

In the single-phase full-bridge inverter circuit of FIG. 4, the switching elements 6 to 9 of the IPMs 2 to 5 are turned on.
Power is supplied to the control circuits 10 to 13 for off control by the AC power supply 30, and the power supply voltage stepped down by the AC power supply 30 is rectified by the rectification circuits 22 to 25 and then via the drive gate circuits 14 to 17. The voltage is applied to the control circuits 10 to 13 of the IPMs 2 to 5. Each control circuit 10
13 to 13 turn on / off the corresponding switching elements 6 to 9 with an on / off command signal from the outside, the DC power supply voltage is AC-converted and applied to the load A. In order to ensure the insulation between the IPMs 2 to 5, the AC power supply 30 is provided via the power supply transformers 26 to 29 as described above.
The power supply voltage from the control circuit 10-13 of each IPM2-5
I am trying to supply it to.

By the way, the power supply circuits of IPMs 2 to 5 as shown in FIG. 4 require a special AC power supply 30 as an IPM control circuit power supply in addition to the single-phase full-bridge inverter circuit. Further, in order to improve the reliability of such a power supply circuit, an expensive UPS (not shown) for the AC power supply 30 is used.
The cost of the single-phase full-bridge inverter circuit increases because it is necessary to install an [uninterruptible power supply] and take measures against momentary voltage drops and blackouts.

Therefore, the present inventor does not need a special AC power source as the IPM control circuit power source, and as long as the DC voltage on the inverter side is established, the power source circuit side has a voltage drop.
Prior to the present invention, an inverter device shown in FIG. 5, for example, was developed prior to the present invention by attempting to develop a low-cost inverter device that does not require a power failure countermeasure. The inverter device of FIG. 5 is based on Japanese Patent Application No. 6-264729 of the present applicant, and will be described below. Note that FIG. 5 shows a case where it is applied to the single-phase full-bridge inverter circuit of FIG. 4, and the same parts as those of FIG.

The inverter device shown in FIG. 5 is a single-phase full-bridge inverter circuit [hereinafter simply referred to as an inverter circuit].
A chopper circuit C is provided between B and the DC power supply 1. The chopper circuit C steps down the DC power supply voltage V 1 of the DC power supply ₁ to a stable and constant value of the control power supply voltage V ₂ and supplies the voltage to the inverter circuit B.
0, diode 70, reactor 71, capacitor 72
Is provided.

The inverter circuit B differs from that shown in FIG. 4 in that the power supply circuits 51 to 54 are installed in front of the control circuits 10 to 13 of the IPMs 2 to 5, respectively. Each power supply circuit 51-
Reference numeral 54 denotes current limiting and voltage dividing resistors 33 to 36 [hereinafter, simply referred to as resistors] provided in front of the drive gate circuits 14 to 17 of the IPMs 2 to 5 and power source voltage establishing Zener diodes 37 to 40 [hereinafter, simply Zener diode], each resistor 33 to 36 and Zener diode 37 to
The capacitor discharge prevention diodes 41 to 44 (hereinafter, simply referred to as diodes) are connected between the connection point of 40 and the electrolytic capacitors 18 to 21. Therefore, the control power supply voltage V from the DC power supply 1 and the chopper circuit C is applied to the control circuits 10 to 13 via the resistors 33 to 36 and the Zener diodes 37 to 40.

Power supply circuits 51 to 54 of the IPMs 2 to 5
Operates according to the following points. First, at the time of initial charging, as shown in FIG. 6, the resistors 33 to ₃ are applied by applying the DC voltage V ₂ from the chopper circuit C before starting the inverter circuit B.
Currents I _D and I _ZD flow through the diodes 41 to 44 and the zener diodes 37 to 40, respectively. The current I _ZD flowing through the Zener diodes 37 to 40 keeps the voltage V _ZD applied to the Zener diodes 37 to 40 at a constant Zener voltage [≈power supply voltage for control], while the current I _ZD flowing through the diodes 41 to 44. _D charges the electrolytic capacitors 18 to 21 and supplies a control current.

Next, during operation of the inverter circuit B, for example, as shown in FIG. 7A, the switching element 6 (8) of the upper IPM 2 (4) is turned off and the lower IP is positioned.
When the switching element 7 (9) of M3 (5) is turned on, a current flows in the direction of the broken line arrow in the figure, the electrolytic capacitor 18 (20) is charged, and the IP located on the upper side.
The DC power supply voltage V _{2 is} applied to the control circuit 10 (12) of the M2 (4).
The power is supplied by.

On the contrary, the switching element 6 (8) of the upper IPM 2 (4) is turned on and the lower IPM 2 is turned on.
When the switching element 7 (9) of 3 (5) is turned off, the points P ₁ and P ₂ of FIG. 7 (a) have substantially the same potential, and the switching element 2 (4) located on the upper side has the ON voltage. As a result, the power supply by the DC power supply voltage V ₂ is hardly performed, and at this time, the IPM3 (5) located on the lower side
Power is supplied to the control circuit 10 (13) by the DC power supply voltage V ₂ .

A resistor 33 which enables the above power supply operation.
The value R of to 36 is, R = [V ₂ -V _ZD] / [I _D / (OFF DUTY (%) /
100)]. Therefore, power is supplied to each of the control circuits 10 to 13 during the on / off cycle of the corresponding switching elements 6 to 9 during the off period.

The chopper circuit C of FIG. 5 is installed corresponding to the voltage fluctuation of the DC power supply 1. For example, when the DC power source 1 is a commercial AC power source converted to DC by a converter, the power source voltage V ₁ of the DC power source 1 fluctuates due to fluctuations in the commercial AC voltage, and a stable output cannot be obtained at the output of the inverter circuit B. is there. Further, in the case where the DC power supply 1 is a battery whose voltage drops due to power consumption, the output of the inverter circuit B may not be able to obtain a predetermined capability due to the voltage drop. In order to prevent these, the chopper circuit C installed in the preceding stage of the inverter circuit B lowers the DC power supply voltage V ₁ to a stable and constant DC voltage V ₂ by the on / off control of the switching circuit 60.

Switching circuit 60 of chopper circuit C
Are the IPMs 2 to 5 of the inverter circuit B and the power supply circuit 5 thereof.
It is composed of the same IPM 61 and power supply circuit 62 as 1 to 54. The IPM 61 comprises a switching element 63 in which diodes are connected in parallel and a control circuit 64 for the main portion, and is packaged with built-in functions such as overcurrent protection, short-circuit current protection, overheat protection, and control power supply voltage drop protection. It is a commercial product. The control power supply voltage drop protection function of the IPM 61 is a function of outputting an error signal and stopping the switch function of the entire switching circuit when the applied control power supply voltage drops below a reference value.

A drive gate circuit 65 is connected to the front stage of the control circuit 64 of the IPM 63, and an electrolytic capacitor 66 is connected in parallel to the front stage of the drive gate circuit 65. Further, in front of the drive gate circuit 65, a current limiting and voltage dividing resistor 67 of the power supply circuit 62 and a power supply voltage establishing zener diode 6 are provided.
8 and the capacitor discharge prevention diode 69 are connected. Then, the power supply voltage V of the DC power supply 1 is applied to the control circuit 64 via the resistor 67 and the Zener diode 68 to supply power. This power supply is also performed during the off period of the switching element 63 in the IPM 61.

The basic operation of the chopper circuit C is shown in the equivalent circuit of FIG.
A description will be given based on the road map and the waveform diagram of FIG. FIG. 8A shows
When the switching element 63 of the IPM 61 is turned on, etc.
FIG. 8B shows a switch of the IPM 61.
An equivalent circuit when the switching element 63 is turned off is shown. Figure
As shown in FIG. 9 (a), the switching element 63 is turned on.
T is the on period when_ON, The off period when turned off is T
_OFF, And the on / off switching cycle is T
Output power supply voltage V of the chopper circuit C₂Is the input power supply voltage V₁of
It becomes the average value in the cycle T [see FIG. 9 (b)], and V₂=
(T_ON/ T) V₁Becomes Therefore, the ON period T_ON0 to
By changing to T, the power supply voltage V ₂Is from 0 to V
₁Is continuously adjusted between. In chopper circuit C
Is the input power supply voltage V₁Output power supply voltage V₂
So that it becomes constant [T_ON/ T] value, that is, the switch
ON period T of the ching element 63_ONThe value of is controlled step by step.
9 (c) shows that the switching element 63 is turned on / off.
Sometimes the current I flowing in the chopper circuit C_r, I_DIs shown,
When the switching element 63 is on, the reactor 52
Limited current I_rRises and turns off the diode
70 due to current I_DFlows.

[0017]

As in the inverter device shown in FIG. 5, each IP of the chopper circuit C and the inverter circuit B is used.
By supplying the power to M using the DC power supply 1, it is not necessary to use an individual AC power supply in consideration of insulation between the circuits, and the voltage of the DC power supply 1 is established. As long as there is no need to worry about momentary voltage drops or power outages, there is no need to take measures against voltage drops or power outages when using individual AC power supplies, and product costs can be reduced. However, in the chopper circuit C of FIG. 5, the fluctuation rate of the power supply voltage drop of the DC power supply 1 becomes high,
This power supply voltage V ₁ is the control power supply voltage V of the inverter circuit B.
_When it drops to about ₂ , I of switching circuit 60
There is a problem that the PM 63 outputs an error signal and the operation of the entire inverter device is stopped.

[0018] That is, when the power supply voltage V ₁ of the DC power supply 1 drops vary due to such power, is necessary to lengthen the ON period T _ON of the switching element 63 of the switching circuit 60 in response to the voltage drop is there. For example, the rated voltage V of the DC power supply 1 is 200v, and the rated voltage V of the inverter circuit B is
When the DC power supply voltage V drops to 150v, the rated voltage of 100v is supplied to the inverter circuit B by the following formula: V ₂ = (T _ON / T) V ₁ 25% of the period T _ON from the rated time
You need to make it longer.

When the ON period T _ON of the switching element 63 is lengthened due to the voltage drop of the DC power supply 1, the OFF period T _OFF of the switching element 63 is shortened accordingly, and the control circuit of the IPM 61 performed in this OFF period T _{OF F.} The power supply time to 64 is shortened. As a result, when the OFF period T _OFF of the switching element 63 becomes short to such an extent that the power supply voltage drop protection function built in the control circuit 64 outputs an error signal, the switching operation of the IPM 61 stops and the inverter device as a whole stops. Defect occurs. Further, due to the occurrence of this problem, there is inconvenience and uneconomical that the allowable voltage fluctuation range of the DC power supply 1 cannot be set large, and there is room for improvement.

It should be noted that it is conceivable to supply power to the control circuit 64 of the IPM 61 in the chopper circuit C by using a separate AC power source and a rectifier circuit as in the case of FIG. As in the case, the product cost becomes high, and the utility value of the chopper circuit C for the inverter device is reduced.

Therefore, the object of the present invention is to
An object of the present invention is to provide an inverter device in which the power supply to the IPM of the chopper circuit is stably continued even if the DC power supply voltage drops, and the inverter operation is continued.

[0022]

SUMMARY OF THE INVENTION The present invention is an inverter device having a chopper circuit for stabilizing a DC power supply voltage to a DC voltage of a predetermined value by a switching operation of a switching circuit and outputting the voltage to an AC conversion inverter circuit. The switching circuit of the chopper circuit includes a switching element and a control circuit for controlling and protecting the switching element.
A PM and a power supply circuit for providing a DC power supply voltage to the control circuit via the resistor and the Zener diode by providing a current limiting and voltage dividing resistor and a power supply voltage establishing Zener diode in the preceding stage of the IPM control circuit In order to achieve the above object, an auxiliary power supply circuit for applying a DC voltage obtained from the AC output voltage of the inverter circuit through the transformer and the rectifier circuit to the switching circuit of the chopper circuit as a control power supply voltage is provided. Is.

[0023]

After the chopper circuit and the inverter circuit operate in the initial stage before the DC power supply voltage drops, the ON period of the switching element of the IPM of the chopper circuit becomes longer and the OFF period becomes shorter due to the drop of the DC power supply voltage. Even if the IPM control power supply amount from the accompanying power supply circuit is insufficient or gone, the power from the output side of the inverter circuit is supplied to the IPM control circuit via the auxiliary power supply circuit,
The switching operation is continuously performed, and the inverter device can be continuously operated.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. It should be noted that the same or corresponding portions as those in FIG. 5 of FIGS. 1 to 3 are denoted by the same reference numerals.

The inverter device of FIG. 1 is characterized in that an auxiliary power supply circuit D is additionally installed between the output terminals 31 and 32 of the inverter circuit B and the switching circuit 60 of the chopper circuit C. The auxiliary power supply circuit D includes, for example, a small transformer 80 and a rectifier circuit 81. That is, the AC voltage V ₃ at the output terminals 31 and 32 of the inverter circuit B is applied to the transformer 8
The voltage is stepped down at 0 and converted to DC voltage V ₄ by the rectifier circuit 81,
This DC voltage V ₄ is applied to the gate circuit 65 of the switching circuit 60 as power source energy of the control circuit 64.

FIG. 2 shows an equivalent circuit of the inverter device shown in FIG. 1 at the initial stage, and FIG. 3 shows an equivalent circuit of the auxiliary power supply circuit D and the switching circuit 60 at the time of operation of the inverter. The voltage / current symbols shown in FIG. A specific example of the circuit configuration content will be described with reference to FIG.

[0027] In the initial stage where the power supply voltage V ₁ of the rated value is turned to the DC power source 1 [2], such that _{V 1 = V S + V ZD} + V 2, selected resistor 67 of the power supply circuit 62 IPM61 To do. With this selection, in the initial stage, the control circuit 64 of the IPM 61 receives power supply from the DC voltage V ₁ of the DC power supply 1 during the OFF period T _{OF F} of the switching element 63, the switching element 63 performs ON / OFF operation, and the inverter The circuit B starts its operation when the rated DC voltage V ₂ is applied.

In operation of FIG. 3, the inverter circuit B
The AC voltage V ₃ is applied to the load A from the output terminals 31 and 32 of the power supply circuit and the power supply energy is supplied to the gate circuit 65 of the IPM 61 through the transformer 80 and the rectifier circuit 81 of the auxiliary power supply circuit D. Let I _R be the current flowing through the resistor 67 during the off period T _OFF of the switching element 63, and I _TR be the current supplied from the auxiliary power supply circuit D to the gate circuit 65 during the operation of the inverter circuit B. I _R > The resistor 67, the transformer 80, and the rectifier circuit 81 are selected so that I _ZD + I _D I _TR > I _ZD + I _D. At this time, the turns ratio of the transformer 80 is selected according to the ratio of the inverter output and the gate voltage.

As described above, when the drop fluctuation rate of the DC power supply voltage V ₁ becomes large, the power supply energy of the IPM 64 is switched to the output power supply energy from the inverter circuit B to supply power to the control circuit 64. The operation of the chopper circuit C and the inverter circuit B is continuously performed. Further, for example, when the rated voltage of the DC power supply 1 is 200 v and the rated voltage of the inverter circuit B is 100 v, the DC voltage V ₁ of the DC power supply 1 needs to be about the rated voltage at the initial stage, but 100 V after the start of the inverter operation.
The operation is continued even if it descends to a certain degree. As a result, the allowable voltage fluctuation range of the DC power supply 1 can be set large, and a wide variety of commercial AC power supplies, battery power supplies, etc. can be selected for the DC power supply 1.

The present invention can be applied to an inverter device having an inverter circuit other than the single-phase full-bridge inverter structure as in the above embodiment.

[0031]

According to the present invention, the DC power supply voltage drops after the operation of the inverter circuit, and the OFF period of the switching element of the IPM of the chopper circuit is shortened, so that the power supply circuit associated with the IPM supplies control power to the IPM. Even if the amount of power supply is insufficient, the power from the output side of the inverter circuit is supplied to the control circuit of the IPM via the auxiliary power supply circuit.
The switching operation is continuously performed, the continuous operation of the inverter device becomes possible, and a highly reliable inverter device can be provided. In addition, since the operation stop of the switching circuit due to the voltage drop of the DC power supply is avoided, it is possible to effectively use the power supply in a wide range such as a commercial AC power supply or a battery power supply where the DC power supply may have a voltage drop. It is possible to provide an inverter device with high efficiency and economical advantages.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of an inverter device according to the present invention.

FIG. 2 is an equivalent circuit diagram of the inverter device of FIG. 1 at an initial stage.

FIG. 3 is an equivalent circuit diagram of a main part of the inverter device of FIG. 1 after the operation of the inverter.

FIG. 4 is a circuit diagram of a conventional inverter device.

FIG. 5 is a circuit diagram of an inverter device which is a premise of the present invention.

6 is a partial circuit diagram of the inverter device of FIG. 5 at an initial stage.

7A is an equivalent circuit diagram showing an operating state in which a switching element of the IPM located on the upper side of the inverter device in FIG. 5 is turned off, and FIG. 7B is an equivalent circuit diagram showing an operating state in which the switching element is turned on.

8 (a) is an equivalent circuit diagram when the switching elements of the chopper circuit in the inverter device of FIG. 5 are turned on,
(B) is an equivalent circuit diagram when the switching element is off.

9 (a) is an on / off waveform diagram of switching elements of a chopper circuit in the inverter device of FIG. 5, (b).
Is a voltage waveform diagram by switching, (c) is a current waveform diagram by switching

[Explanation of symbols]

1 DC power supply A load B inverter circuit C chopper circuit D auxiliary power supply circuit 60 switching circuit 61 Intelligent power module [IPM] 62 Power supply circuit 63 Switching element 64 Control circuit 67 Current limiting and voltage dividing resistor 68 Power supply voltage establishing Zener diode 80 Transformer 81 Rectifier circuit

Claims (1)

[Claims] 1. An inverter device comprising a chopper circuit which stabilizes a DC power supply voltage to a DC voltage of a predetermined value by a switching operation of a switching circuit and outputs the DC voltage to an AC converting inverter circuit, wherein the switching circuit of the chopper circuit comprises: An intelligent power module with a built-in switching element and a control circuit for controlling and protecting the switching element, and a resistor for current limiting and voltage dividing and a Zener diode for establishing a power supply voltage are provided in the preceding stage of the control circuit of this intelligent power module. In a power supply circuit that applies a power supply voltage to a control circuit through the resistor and a Zener diode, an AC output voltage of the inverter circuit is obtained through a transformer and a rectifier circuit, and a DC voltage is supplied to a switching circuit of the chopper circuit. As the power supply voltage for control Inverter apparatus characterized by annexed auxiliary power supply circuit applied to.