KR20000070269A - Power converter - Google Patents

Abstract

The present invention provides a power conversion device that can reduce the size of the circuit by eliminating other power supplies such as a switching regulator and obtain a power supply based on the positive electrode side bus line of the real current power supply at low cost.

When the upper arm switching element T1 is " on ", the U point potential becomes almost the same as the P point potential, through the diode D7 on the positive electrode side of the insulated power supply 21 for driving the switching element T1. IC1 flows into the condenser C1 to charge the cone sensor C1.

The power source Vc is used as the power source based on the positive electrode side bus line P of the direct current power source by the capacitor C1.

Description

Power converter {POWER CONVERTER}

7 is a diagram showing a circuit configuration of a three-phase voltage PWM inverter device of a conventional three-phase bridge circuit.

In the figure, 11 is a DC power source, P is a positive side bus of the DC power source 11, N is a negative side bus of the DC power source 11, 12 is a direct current power of the DC power source 11, and AC is a desired frequency and voltage. Inverter for converting into electric power, T1 to T6 are switching elements, D1 to D6 are diodes connected in anti-parallel to switching elements T1 to T6, and 21 to 26 are insulated from each other to drive switching elements T1 to T6. Power source, 31 to 36 are driving circuits for driving the switching elements T1 to T6, respectively, Vp is a power source based on the positive electrode side bus line P of the DC power source 11, U, V and W are output terminals, 50 is a motor driven by the inverter device.

The inverter 12 is a phase arm circuit in which an upper arm circuit (switching element T1 and a diode D1 are inversely connected in parallel and connected in parallel between the positive poles of the DC power source 11, and the phase arm in which the switching element T2 and the diode D2 are in parallel and in parallel). Circuit, reverse arm and circuit of switching element T3 and diode D3) and lower arm circuit (low arm circuit and reverse switching of switching element T4 and diode D4, switching element T5 and diode D5) A three-phase bridge circuit composed of three sets of a lower arm circuit in parallel, a lower arm circuit in which the switching element T6 and the diode D6 are inversely connected in parallel, and a driving power source (21 to 26) and a driving circuit (31 to 36). It is composed.

Fig. 8 shows a circuit configuration of a conventional three-phase voltage PWM inverter device, and has an inrush current limiting circuit constructed using a thyristor.

12, 21-26, 31-36, 50, T1-T6, D1-D6, P, N, U, V, and W are the same as FIG. 7, and the description is abbreviate | omitted.

R, S, T is AC power, 13 is a rectifier with diode bridge to rectify and convert AC power (R, S, T) into DC power, 14 is connected between bus line P and N of DC power, A smoothing capacitor for smoothly controlling the inverter 12 by maintaining a constant DC voltage as an output of (13), R5 is a resistor for limiting inrush current to limit inrush current to the smoothing capacitor 14, and 15 is a resistance. Thyristor shorting (R5), R6 is a resistance for limiting the gate current of the thyristor 15, 16 is a photocoupler for the firing of the thyristor 15, 17 is a control circuit for controlling the firing signal of the photocoupler 16 Is a power supply for the gate control of the thyristor 15 and the photocoupler firing.

An inrush current limiting circuit is constituted by the power supply Vp, the resistor R5, the thyristor 15, the resistor R6, the photocoupler 16, and the control circuit 17.

Next, the operation of the inrush current circuit will be described.

When the AC power supply (R, S, T) is turned on, the charging current to the smoothing capacitor 14 flows to the power rectifier 13, but since the smoothing capacitor 14 is generally large in capacity, the charging current is excessive. An inrush current is obtained.

Therefore, in general, the resistor R5 is inserted into the circuit of the smoothing capacitor 14 to limit the inrush current to the smoothing capacitor 14 flowing when the AC power supplies R, S, and T are turned on by the resistor R5. To protect the power rectifier 13.

When the smoothing capacitor 14 is charged after a certain time, the thyristor 15 is ignited to short-circuit both ends of the resistor R5 to start operation.

The firing ("on", "off" operation) of the thyristor 15 is performed by the resistor R6, the photocoupler 16 and the control circuit 17.

In a power supply Vp such as a switching regulator based on the positive electrode bus P of the DC power supply, a current is supplied to the gates of the photocoupler 16 and the thyristor 15.

Fig. 9 is a diagram showing the configuration of a current detection circuit for detecting current in the positive electrode side bus line of a conventional three-phase voltage PWM inverter device.

11, 12, 21-26, 31-36, 50, P, N, U, V, and W are the same as FIG. 7, and the description is abbreviate | omitted.

Po is the positive electrode side bus of the DC power supply 11, R7 is the resistance for current detection connected in series between the positive electrode side bus P and the Po of the DC power source 11, 18 is the positive electrode of the DC power source. An insulation amplifier for insulating the side bus, 19 is a detection circuit for detecting current, and Vp is a power supply for driving the insulation amplifier 18, based on the positive electrode side bus line Po of the DC power supply.

The input of the insulation amplifier 18 is connected to both ends of the resistor R7, and the output of the insulation amplifier 18 is connected to the detection circuit 19.

The positive electrode side of the power source Vp is connected to the power input unit A of the insulation amplifier 18.

When a current flows to the positive electrode side of the DC power source 11, voltage is generated at both ends of the resistor R7 connected in series between the positive electrode side bus line P and P0 of the DC power source 11.

The voltage generated at both ends of the resistor R7 is input to the detection circuit 19 via the insulation amplifier 18 to detect the current flowing through the positive bus side of the DC power supply 11.

Conventional power converters, such as inverter devices or high power factor converters, are configured as described above. When the power supply such as the protection circuit is based on the positive electrode side of the DC power supply, the switching is based on the positive electrode side bus of the DC power supply. Another power supply such as a regulator is required, and the circuit size becomes large, resulting in a problem of price increase.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, for example, to eliminate the need for other power supplies such as switching regulators, to reduce the circuit size, and to obtain a power supply based on the positive electrode side bus of the current power supply at low cost. It is an object to obtain an inverter.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter such as an inverter device or a high power factor converter, and more particularly, to a power converter having a power source based on a positive side bus of a direct current power source.

1 is a diagram showing Embodiment 1 of a circuit of a voltage type PWM inverter device according to the present invention.

2 is a view showing the operation principle of obtaining a PWP pulse of a voltage type PWM inverter device generally used.

Fig. 3 is a diagram showing the circuit configuration of the voltage type PWM inverter device according to the second embodiment of the present invention.

Fig. 4 is a diagram showing the circuit configuration of the voltage PWM inverter device according to the third embodiment of the present invention.

Fig. 5 is a diagram showing the circuit configuration of the voltage type PWM inverter device according to the fifth embodiment of the present invention.

Fig. 6 is a diagram showing the circuit configuration of the voltage type PWM inverter device according to the sixth embodiment of the present invention.

7 is a diagram showing the circuit configuration of a three-phase voltage PWM inverter device by a conventional three-phase bridge circuit.

Fig. 8 is a diagram showing a circuit configuration of a conventional three-phase voltage PWM inverter device, and includes an inrush current limiting circuit constructed using a thyristor.

Fig. 9 is a diagram showing the configuration of a current detection circuit for detecting current in the positive side bus of a conventional three-phase voltage PWM inverter device.

Example 1

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows Example 1 of the circuit of the voltage type PWM inverter apparatus by this invention.

In the figure, 11 is a DC power source, P is a positive side bus line of the DC power source 11, N is a negative side bus line of the DC power source 11, 12 is a DC power source in the DC power source 11, and alternating current of a desired frequency and voltage is shown. An inverter converting into electric power, U, V, W are output terminals, and 50 are motors driven by an inverter device.

The inverter 12 is a phase arm circuit (a phase arm circuit in which the switching element T1 is connected in parallel with the diode D1, and a phase arm circuit in which the switching element T2 is connected in parallel with the diode D2). Phase arm circuit with anti-parallel connection of T3 and diode D3) and lower arm circuit (Haarm circuit with anti-parallel connection of switching element T4 and diode D4, Haarm circuit with anti-parallel connection between switching element T5 and diode D5, switching element T6 And a three-phase bridge circuit comprising three sets of a lower arm circuit in which the diode D6 is inversely connected in parallel with each other, the driving power sources 21 to 26, and the driving circuits 31 to 36.

D7 to D9 are reverse voltage block diodes, and C1 is a capacitor for accumulating energy to secure a voltage, and has an effect of removing ripple.

Vc is a power supply by the capacitor C1, and ic1 is a current flowing through the capacitor C1.

The anode side of the diodes D7 to D9 is connected to the positive electrode side of the driving power sources 21 to 33, respectively, and the cathode side of the diodes D7 to D9 is connected to the capacitor C1, and the other of the capacitor C1 is different. The terminal is connected to the positive electrode side bus line P of the DC power supply 11.

The following operation will be described.

When the upper arm switching element T1 is turned on, the U point potential becomes almost equal to the P point potential, so that the capacitor (D7) is connected to the positive electrode side of the insulated power supply 21 for driving the switching element T1. ICl current flows into C1) to charge the capacitor C1.

Similarly, when the upper and lower switching elements T2 and T3 are "on", the capacitors (D8, D9) are connected through the diodes D8 and D9 on the positive electrode side of the insulated power supplies 22 and 23 to drive the switching elements T2 and T3. Charge C1).

2 is a view showing the operation principle of obtaining a PWM pulse of a voltage type PWM inverter device generally used, (a), (b), (c) is a reference signal of a sine wave (R phase, S phase, T phase) And (a), (e), (f), and (g) show the switching timing of the switching element compared with the carrier wave of the triangular wave (hereinafter referred to as the triangular wave).

The operation of charging the capacitor C1 will be described with reference to FIGS. 1 and 2.

In the voltage-type PWM inverter device, a PWM pulse was obtained by comparing a sinusoidal reference signal with a triangular wave, and the switching elements T1 to T3 of the phase arm were "on" and low when the sinusoidal reference signal was higher than the triangular wave. Is turned off.

Since the triangular waves are equally spaced and the height of the sine wave reference signal is " 0 " or more, the time when any one of the phase arms switching elements T1 to T3 is " on " is longer than that of " off ".

While the inverter device is in operation, the sinusoidal reference signal is larger than " 0 ", and the time for which any of the phase arms switching elements T1, T2, and T3 is " on " is longer than the " off " time. The charging time is longer than the discharge time and is always charged, so that a power supply Vc having a substantially constant DC voltage based on the sinusoidal side of the DC power supply can be made.

With the above configuration, there is an effect that the power supply Vc by the capacitor C1 can be used as a power supply based on the positive electrode side bus line P of the DC power supply.

Example 2

Fig. 3 is a diagram showing the circuit configuration of the voltage PWM inverter device according to the second embodiment of the present invention.

11, 12, 21 to 36, 31 to 36, P, N, T1 to T6, D1 to D6, D7 to D9, U, V, W, C1, Vc, and 50 are the same as those of Example 1 above. 1 and description thereof is omitted.

R1 to R3 are current suppression limiting resistors, and ic2 is a current flowing through the capacitor C1.

The anode side of the diodes D7 to D9 is connected to the positive electrode side of the driving power sources 21 to 23 via the resistors R1 to R3, respectively, and the cathode side of the diodes D7 to D9 is connected to the capacitor C1. And the other terminal of the capacitor C1 are connected to the positive electrode side bus line P of the DC power supply 11.

Next, the operation of the second embodiment will be described.

When the switching element T1 of the upper arm is "on", the U point potential becomes almost the same as the P point potential, so that the resistor R1 and the positive electrode side of the insulated driving power source 21 for driving the switching element T1. Ic2 flows into the capacitor C1 through the diode D7 to charge the capacitor C1.

Similarly, when the switching elements T2 and T3 of the upper arm are "on", the capacitor C _{1 is} connected to the positive electrode side of the driving power supply 22 and 23 through the resistors R2 and R3 and the diodes D8 and D9. To charge.

According to the second embodiment, the power supply Vc by the capacitor C ₁ is used as the power supply based on the positive electrode side bus line P of the DC power supply, and the resistance is provided on the positive electrode side of the driving power supplies 21 to 23. The anode side of the diodes D7 to D9 are connected via R1 to R3, respectively, so that the excessive inrush current at the start of charging to the capacitor C1 is prevented even when the capacitor C1 is increased. By suppressing by R1-R3, destruction of the diodes D7-D9 can be prevented.

Example 3

Fig. 4 is a diagram showing the circuit configuration of the voltage PWM inverter device according to the third embodiment of the present invention.

11, 12, 21 to 26, 31 to 36, P, N, T1 to T6, D1 to D6, D7 to D9, U, V, W, C1, Vc, and 50 are shown in Example 1 above. Same as 1, the description thereof is omitted.

R ₄ is a current limiting resistor, and ic 3 is a current flowing through the capacitor C1.

The anode side of the diodes D7 to D9 is connected to the positive electrode side of the driving power sources 21 to 23, respectively, and the cathode side of the diodes D7 to D9 is connected to the capacitor C1 via the resistor R4. The other terminal of the capacitor C1 is connected to the positive electrode side bus line P of the DC power supply 11.

Next, operation of the third embodiment will be described.

When the switching element T1 of the upper arm is "on", the U point potential becomes almost the same as the P point potential, and is supplied to the capacitor C1 through the diode D7 and the resistor R4 on the positive electrode side of the power supply 1. The current of iC3 flows to charge the capacitor C1.

Similarly, when the upper and lower switching elements T2 and T3 are "on", the diodes D8 and D9 and the resistor R4 on the positive side of the insulated power supplies 22 and 23 for driving the switching elements T2 and T3. The capacitor C1 is charged.

According to the operation principle of the voltage-type PWM inverter device described in FIG. 2 in Embodiment 1, the charging time of the capacitor C1 is longer than the discharge time, and is always charged, and is based on the electrode side P of the DC power supply. It is possible to make a power supply (Vc) having a nearly constant DC voltage.

In the second embodiment, the resistors R1 to R3 are respectively connected to the diodes D7 to D9 as the current suppression limiting resistor. In the third embodiment, one resistor R4 is connected to the diodes D7 to D9. The number of parts can be reduced by connecting between the cathode side and the capacitor C1.

Example 4

In the above embodiments 1 to 3, the capacitor C1 is charged by the operation during operation of the voltage type PWM inverter device of the three-phase bridge circuit, and the power source Vc on the positive electrode side of the direct current power source is turned on. Although an example is shown, the capacitor C1 is charged by controlling at least one of the phase arms switching elements T1 to T3 to be "on" in a transient state such as starting operation, thereby charging the capacitor C1 and providing a positive pole of the DC power supply. The power supply Vc can be made with respect to the side.

Example 5

5 is a diagram showing the circuit configuration of the voltage-type PWM inverter device according to the embodiment 5 according to the present invention.

12, 21 to 26, 31 to 36, P, N, T1 to T6, D1 to D6, D7 to D9, R4, U, V, W, C1, Vc, and 50 are shown in FIG. The description is the same as in the following.

13 is a power rectifier comprising a diode bridge that rectifies and converts AC power (R, S, T) into DC power, and 14 is connected between bus lines P and N of the DC power supply so that the DC voltage that is the output of the power rectifier 13 is constant. And a smoothing capacitor for smoothly operating the control of the inverter 12, R5 is a resistor for limiting the inrush current to limit the inrush current to the smoothing capacitor 14, 15 is a thyristor for shorting the resistor R5, R6 Is a resistance for limiting the gate current of the thyristor 15.

The anode side of the diodes D7 to D9 is connected to the positive electrode side of the driving power sources 21 to 23, respectively, and the cathode side of the diodes D7 to D9 is connected to the capacitor C1 via the resistor R4. The other terminal of the capacitor C1 is connected to the positive electrode side bus line P of the DC power supply.

The resistor R6 is connected to the connection portion of the capacitor C1 and the resistor R4, and the other terminal of the resistor R6 is connected to the gate of the thyristor 15.

In Example 5, the power supply Vc made of the capacitor C1 as shown in Fig. 1, Fig. 3 or Fig. 4 is used for the inrush current limiting circuit using the thyristor.

Next Example 5 will be described.

In the inrush current limiting circuit using the thyristor, after the AC power supply (R, S, T) is input, the smoothing capacitor 14 is charged via the resistor R5 to suppress the increase of the inrush current to the diode of the power rectifier 13. To protect the diode.

After the smoothing capacitor 14 completes charging, the thyristor 15 is fired to short-circuit both ends of the resistor R5.

The thyristor 15 calls by supplying a current to the gate of the thyristor 15 using the power supply Vc made in the capacitor C1.

In the inrush current limiting circuit in which the resistor R5 connected in series to the positive electrode side bus of the DC power supply and the thyristor 15 are connected in parallel, the power supply Vc of the capacitor C1 is connected to the positive electrode side bus of the DC power supply ( Since it is used as a power source based on P), no other power source such as a switching regulator is necessary, and a switch (for example, a photocoupler 16) for firing the thyristor shown in the prior art is also unnecessary.

In addition, the charging of the capacitor C1 is performed only during the operation of the voltage-type PWM inverter device of the three-phase bridge circuit, so that the control circuit 17 of the inrush current limiting circuit is also unnecessary.

Example 6

Fig. 6 is a diagram showing the circuit configuration of the voltage type PWM inverter device according to the sixth embodiment of the present invention.

11, 12, 21 to 26, 31 to 36, P, N. T1 to T6, D1 to D6, D7 to D9, R4 _, U, V, W, C1, Vc, and 50 are shown in Example 3 above. Same as FIG. 4, and description thereof is omitted.

Po is the positive electrode side bus of the DC power supply 11, R7 is the resistance for current detection connected in series between the positive electrode side bus P and the Po of the DC power source 11, 18 is the positive electrode of the DC power source. It is an insulation amplifier to insulate side buses.

The input of the insulation amplifier 18 is connected to both ends of the resistor R7, and the output of the insulation amplifier 18 is connected to the detection circuit 19.

The positive electrode side of the power supply V _C is connected to the power input unit A of the insulation amplifier 18.

Example 6 is a voltage-type PWM inverter device comprising a three-phase bridge circuit, wherein a power supply Vc based on the positive side bus line of a DC power supply is a resistor R7, an insulation amplifier 18, and a detection circuit 19 It is used as a power supply for the insulation amplifier 18 of the rectifier detection circuit composed of

Next, the operation of the sixth embodiment will be described.

When a current flows to the positive electrode side of the DC power source 11, voltage is generated at both ends of the resistor R7 connected in series between the positive electrode side bus line P and Po of the DC power source 11.

The voltage generated at both ends of the resistor R7 is input to the detection circuit 19 via the insulation amplifier 18 to detect the current flowing in the positive electrode side bus line of the DC power supply 11.

Since the voltage Vc of the capacitor C1 can be used as a power source based on the positive electrode side bus line Po of the DC power source, other power sources such as a switching regulator are unnecessary.

By the way, in Example 5 and Example 6 mentioned above, the example which uses the power supply Vc of the capacitor | condenser C1 of Example 3 as a power supply based on the positive electrode side bus | line of a DC power supply was mentioned, but the said The same effect is obtained also when the power supply Vc of the capacitor | condenser C1 of Example 1, Example 2, or Example 4 is used.

In the above example, reference has been made to three phase examples, but it goes without saying that they can be used in voltage-type PWM inverter devices composed of bridge circuits having single phase or four phases or more, and other power converters, for example, high power factor converters.

As described above, the present invention has the following effects.

In the power conversion device according to the present invention, only a diode and a capacitor are used to configure the power supply Vc based on the positive electrode side bus line of the DC power supply, and thus, the size of the circuit is miniaturized because other power supplies such as a switching regulator are not necessary. Inexpensive power converter is obtained.

In addition, since the current flowing through the diodes D7 to D9 is suppressed by the resistors R1 to R3, an excessive breakdown current can be suppressed at the start of charging to the capacitor C1 even when the capacitor C1 is increased in capacity. The number of diodes D7 to D9 can be protected.

In addition, since the current flowing through the diodes D7 to D9 is suppressed by the resistor R4, the number of parts is reduced and the circuit size can be reduced.

In addition, in the transient state at the start of operation or the like, at least one of the upper arm switching elements T1 to T3 is controlled to be "on", so that the capacitor C1 is also in the transient state at the start of operation. Vc is used as the power source based on the positive side bus of DC power.

In the inrush current limiting circuit in which a resistor connected in series to the positive electrode side bus of the DC power supply and a thyristor for shorting the resistance are connected in parallel with the resistance, the power supply Vc is set based on the positive electrode side bus of the DC power supply. Since it is used as a power supply, it is unnecessary to switch other power supplies such as switching regulators and thyristors, and the charging of the capacitor C1 is performed only while the voltage type PWM inverter device of the three-phase bridge circuit is operated. The control circuit 17 of the inrush current limiting circuit is also unnecessary, thereby miniaturizing the circuit size.

Also, in a current detection circuit using an insulation amplifier and a detection circuit in which a resistor connected in series with a positive electrode side bus of a DC power supply and a voltage of a resistor are insulated from the positive electrode side bus, the power supply Vc is connected to the positive electrode side bus of the DC power supply. By using it as a reference power source, other power sources such as switching regulators are unnecessary, and the circuit scale is downsized.

The power conversion device according to the present invention comprises at least two sets of phase-arm circuits in which the switching elements and the diodes are in parallel and parallel connection, and a lower arm circuit in which the switching elements and the diodes are in parallel and parallel connection. A bridge circuit connected to the drive circuit, an insulated driving power supply for driving the switching element of the upper arm circuit, a driving power supply insulated for driving the switching element of the lower arm circuit, and driving the switching element of the upper arm circuit And a capacitor having an anode side connected to the positive electrode side of the driving power supply insulated, and a capacitor having one terminal connected to the cathode side of the diode and the other terminal connected to the positive side of the DC power supply. .

Moreover, in order to drive the switching element of the said phase-arm circuit, a resistor is connected in series with the diode which transmits the anode side to the positive electrode side of the insulated driving power supply.

Further, in order to drive the switching element of the phase-arm circuit, a resistor is connected between the cathode side connection portion of the diode and the capacitor connected to the anode side of the insulated driving power supply.

At the start of operation, at least one of the phase arm switching elements is controlled to be "on".

An inrush current limiting circuit comprising a resistor connected in series to a positive electrode side bus of a DC power supply and a thyristor connected in parallel with the resistance, and one terminal is provided as a cathode power supply for this diode. And the voltage of the capacitor which connected the other terminal to the positive electrode side of DC power supply are used.

In addition, a resistor connected in series to the positive electrode side bus of the DC power supply, an insulated amplifier for insulating the voltage of the resistance from the positive electrode side bus, and a current detecting circuit comprising a detection circuit, the power supply for driving the insulation amplifier For example, one terminal is connected to the cathode side of the diode and the other terminal is connected to the positive electrode side of the DC power supply to use the voltage of the capacitor.

As described above, the power converter according to the present invention is suitable for use as a power converter using a power source based on the positive electrode side bus bar of a DC power source.

Claims (6)

A phase circuit having at least two pairs of phase-arm circuits in which the switching elements are connected in parallel with the diodes, and a lower arm circuit in which the switching elements are connected in parallel with the diodes; A driving power source insulated for driving the switching element of the power supply, an insulated driving power source for driving the switching element of the lower arm circuit, and an insulated driving power source for driving the switching element in the upper arm circuit. A power converter comprising: a diode connected to an anode side; and a capacitor connected to one cathode terminal of the diode and another terminal connected to the positive electrode side of the DC power supply. The method of claim 1, And a resistor is connected in series to a diode which connects the anode side to the positive electrode side of the insulated driving power supply for driving the switching element of the phase-arm circuit. The method of claim 1, And a resistor is connected between the cathode side connection portion of the diode and the capacitor connecting the anode side to the positive electrode side of the insulated driving power source for driving the switching element of the phase-arm circuit. The method of claim 1, At the start of operation, at least one of the phase arm switching elements is controlled to be " on " The method of claim 1, Inrush current limiting circuit composed of a resistor connected in series to the positive electrode side bus of a DC power supply, and a thyristor connected in parallel with this resistance, and as a power supply for this thyristor, one terminal is connected to the cathode side of this diode. And a voltage of the capacitor connected to another terminal of the DC power supply to the positive electrode side. The method of claim 1, A resistor connected in series to the positive electrode side bus of a DC power supply, an insulation amplifier for isolating the voltage of this resistance from the positive electrode side bus line, and a current detection circuit comprising a detection circuit and a power supply for driving the insulation amplifier, And a voltage of the capacitor connected with one terminal to the cathode side of the diode and the other terminal connected to the positive electrode side of the DC power supply.