JPH06292364A - Power supply device - Google Patents

Abstract

PURPOSE:To suppress the deterioration of electromagnetic environment of a load by connecting the connection point of first and second capacitors and the tap of a tap inductance connected to a power supply terminal in parallel. CONSTITUTION:The series circuit of smoothing capacitors CA and CB and a load 3 are connected between a pair of power lines 7 and 8 connected to the DC output terminal of a converter 1. A connection point N of the capacitors CA and CB is connected to the tap of a tap inductance LT. Namely, since the tap point N is connected to the tap, the neutral point at the side of an input power supply E and the voltage between DC power lines 7 and 8 do not fluctuate greatly. Further, the voltage between the neutral point of the load 3 and that at the side of the power supply E is scarcely disturbed by the switching of the converter 1, thus suppressing the deterioration of the electromagnetic environment of the load 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device, and more particularly to a power supply device having a good electromagnetic environment.

[0002]

2. Description of the Related Art FIG. 2 is an electric circuit diagram showing a conventional power supply device. With reference to FIG. 2, the AC power source E is a power source terminal T1,
Connected to T2. A pair of AC input terminals of the converter 1, which is composed of four switches Q1, Q2, Q3, Q4 connected in a bridge, is connected to a power supply terminal T1, via a reactor L.
Connected to T2. Switches Q1, Q2, Q3, Q4
Consists of a power MOSFET with a built-in freewheeling diode. The converter 1 converts AC power into DC power. The smoothing capacitor C and the load 3 are connected between the pair of power lines 7 and 8 connected to the DC output terminal of the converter 1. The converter 1 controls the DC voltage of the output of the converter by on / off controlling each of the switches Q1 to Q4.

Here, the conventional problems will be described.
The switches Q1 and Q3 of the converter 1 are turned on, and the switch Q
When Q2 and Q4 are turned off, the potential of the power line 7 becomes equal to that of the power supply terminal T2, and when the switches Q1 and Q3 are turned off and the switches Q2 and Q4 are turned on, the potential of the power line 8 and the power supply terminal T2 are changed. Will be equal. Therefore,
Conventionally, the voltage between the neutral point potential of the power source E and the neutral point potentials of the DC power lines 7 and 8 has fluctuated greatly due to the switching operation of the switches Q1 to Q4 of the converter 1. Due to this fluctuation, the electromagnetic environment of the load 3 was extremely deteriorated. Furthermore, this fluctuation induces interference noise in other electronic devices via the stray capacitances CSP, CSN, etc. of the DC lines 7, 8 and pollutes the electromagnetic environment.

[0004]

Therefore, the main object of the present invention is to suppress the deterioration of the electromagnetic environment of the load. Further, another object of the present invention is to suppress application of electromagnetic interference noise to other electronic devices and to reduce electrical interference noise.

[0005]

A power supply device for supplying electric power to a load, the converter converting AC power from the power supply into DC power, and first and second serially connected output sides of the converter. A capacitor is provided, and the connection point between the first capacitor and the second capacitor is connected to the tap of the tap inductance or the neutral point terminal connected in parallel to the power supply terminal.

[0006]

[Operation] By connecting the tap of the tap inductance connected in parallel to the power supply terminal or the neutral point terminal to the connection point of the first and second capacitors connected in series on the output side of the converter, The adverse effect of the switching of the converter on the electromagnetic environment is effectively suppressed.

[0007]

1 is an electric circuit diagram showing a first embodiment of the present invention. Referring to FIG. 1, AC power supply E is connected to power supply terminals T1 and T2. In addition, power supply terminals T1, T
An inductor LT with a center tap is connected between the two. The windings of the inductance LT are tightly coupled to each other, and the inductance LT has a high impedance with respect to the frequency of the AC power source E, and the exciting current flowing through the inductance LT is small. A pair of AC input terminals of the converter 1, which is composed of four switches Q1, Q2, Q3, Q4 connected in a bridge, are reactors L1, L
2 is connected to power supply terminals T1 and T2. Each of the switches Q1, Q2, Q3, Q4 is composed of a power MOSFET having a freewheeling diode built therein. Converter 1
Is for converting AC power to DC power. Between the pair of power lines 7 and 8 connected to the DC output terminal of the converter 1, the series connection circuit of the smoothing capacitors CA and CB and the load 3 are connected. The connection point N between these capacitors CA and CB is connected to the tap of the inductance LT.

Here, the role of connecting the tap of the inductance LT and the connection point N will be described. When the connection point N and the tap are not connected, when the switches Q1 and Q3 of the converter 1 are turned on and the switches Q2 and Q4 are turned off, the potential of the connection point N is about the voltage of the capacitor CA from the neutral point potential of the power source E. Down and switch Q1,
When Q3 is off and the switches Q2 and Q4 are on, the potential at the connection point N is about the capacitor CB from the neutral point potential of the power source E.
Voltage rises. Therefore, due to the high-frequency switching operation of the converter 1, a high-frequency voltage is generated between the neutral point of the power source E or the tap of the inductance LT and the connection point N. Therefore, the voltage between the neutral point on the power source E side and the connection point N fluctuates significantly due to switching. In order to suppress this fluctuation, the tap and the connection point N are connected. That is, since the connection point N is connected to the tap, the voltage between the neutral point of the input power source side and the DC power lines 7 and 8 does not fluctuate significantly due to the switching operation of the switches Q1-Q4 of the converter 1. . Furthermore, the voltage between the neutral point of the load 3 and the neutral point on the side of the power source E is hardly disturbed by the switching of the converter 1. Therefore, the voltage between the neutral point on the load 3 side and the neutral point on the power supply E side is hardly affected by the switching of the converter 1. As a result, it works very effectively in reducing the interference noise to the load 3 and other electronic devices.

Next, the roles of the reactors L1 and L2 will be described. If there is no reactor L1 or L2,
Due to the high-frequency switching operation of the converter 1, an excessive high-frequency current is generated via the connection line PN that connects the tap of the inductance LT and the connection point N. As a result, an excessive high-frequency current flows through the switches Q1-Q4, which leads to the destruction of these switches Q1-Q4. However, as shown in FIG. 1, by connecting the reactors L1 and L2 to the power line, the excessive high frequency current flowing through the connection PN is effectively suppressed by the reactors L1 and L2, and the switches Q1 to Q4 are destroyed. Avoided.

FIG. 3 is an electric circuit showing a second embodiment of the power supply device. In the embodiment shown in FIG. 3, the inductance LT shown in FIG. 1 is removed, and a pair of AC power lines of a three-wire type power source E0 is connected to power source terminals T1 and T2 instead of the power source E of FIG. In addition, the neutral wire of the three-wire type power source E0 is connected to the neutral point terminal of the power supply device, and the neutral point terminal P is connected to the connection point N via the connection line PN. Is the same as.

Now, the role of connecting the neutral point terminal P and the connection point N will be described. When the connection point N and the neutral point terminal P are not connected, the switch Q of the converter 1
When 1 and Q3 are turned on and switches Q2 and Q4 are turned off, the potential of the connection point N is lowered by about the voltage of the capacitor CA from the neutral potential of the power source E0, and the switches Q1 and Q3 are turned on.
When the switch is turned off and the switches Q2 and Q4 are turned on, the potential of the connection point N rises from the neutral point potential of the power source E0 by about the voltage of the capacitor CB. Therefore, due to the high frequency switching operation of the converter 1, a high frequency voltage is generated between the neutral point terminal P and the connection point N. Therefore, the voltage between the neutral point terminal P and the connection point N fluctuates greatly due to switching. In order to suppress this fluctuation, the neutral point terminal P and the connection point N are connected. That is, since the connection point N is connected to the neutral point terminal P, the voltage between the neutral point on the power source E side and the DC power lines 7 and 8 is caused by the switching operation of the switches Q1-Q4 of the converter 1. Does not fluctuate significantly. Furthermore, the neutral point of the load 3 and the power source E
The voltage to and from the neutral point on the side is not disturbed by the switching of the converter 1. Therefore, the voltage between the neutral point of the load 3 and the neutral point on the side of the power source E is hardly or not affected by the switching of the converter 1. As a result, it works very effectively in reducing the interference noise to the load 3 and other electronic devices.

Next, the roles of the reactors L1 and L2 will be described. If there is no reactor L1 or L2,
Due to the high frequency switching operation of the converter 1, an excessive high frequency current is generated via the connection line PN connecting the neutral point terminal P and the connection point N. As a result, an excessive high-frequency current flows through the switches Q1-Q4, and these switches Q1-Q4
Leading to the destruction of. However, as shown in FIG. 3, by connecting the reactors L1 and L2 to the power line,
Excessive high frequency current flowing through the connection PN is the reactor L1,
L2 effectively suppresses the destruction of the switches Q1-Q4.

FIG. 4 is an electric circuit showing a third embodiment of the power supply device. In the embodiment shown in FIG. 4, the reactors L1 and L2 shown in FIG. 1 are removed, and a converter 1DD including diodes D1, D2, D3 and D4 is used instead of the converter 1 shown in FIG. Other configurations are the same as those in FIG.

Here, the role of connecting the tap of the inductance LT and the connection point N will be described. When the connection point N and the tap are not connected, when the diodes D1, D2, D3 and D4 of the converter 1DD are all turned off,
The potential of the connection point N becomes uncertain with respect to the neutral point potential of the power source E, and therefore the potentials of the output lines 7 and 8 of the converter become uncertain. Therefore, there is a problem in that the potential of the output line is easily affected by the disturbing noise and becomes unstable. However, since the connection point N is connected to the tap,
Even if all the diodes D1 to D4 of the converter 1DD are turned off, the voltage between the neutral point on the input power source side and the DC power lines 7 and 8 does not fluctuate significantly due to the influence of disturbance noise. Therefore, the voltage between the neutral point on the load 3 side and the neutral point on the power supply E side is hardly affected by the on / off of the diode of the converter 1DD. As a result, it effectively acts to reduce the disturbance noise to the load 3.

FIG. 5 is an electric circuit showing a fourth embodiment of the power supply device. In the embodiment shown in FIG. 5, the inductance LT shown in FIG. 4 is removed, and a pair of AC power lines of the three-wire type power source E0 is connected to the power source terminals T1 and T2 instead of the power source E of FIG. Further, the neutral wire of the three-wire type power supply E0 is connected to the neutral point terminal of the power supply device, and the neutral point terminal P is connected to the connection point N via the connection line PN. Is the same as.

Now, the role of connecting the neutral point terminal P and the connection point N will be described. When the connection point N and the neutral point terminal P are not connected, when the diodes D1, D2, D3 and D4 of the converter 1DD are all turned off, the connection point N
The potential of is uncertain with respect to the neutral point potential of the power source E,
Therefore, the potentials of the output lines 7 and 8 of the converter become uncertain. Therefore, there is a problem in that the potential of the output line is easily affected by the disturbing noise and becomes unstable. However, since the connection point N is connected to the neutral point terminal P, even if all the diodes D1 to D4 of the converter 1DD are turned off, the neutral point between the input power source side and the DC power lines 7 and 8 are connected. The voltage does not fluctuate significantly due to the influence of disturbance noise. Therefore, the voltage between the neutral point on the load 3 side and the neutral point on the power source E0 side is hardly affected by the on / off of the diode of the converter 1DD. As a result, it effectively acts to reduce the disturbance noise to the load 3.

The present invention is not limited to the particular embodiment of FIGS. 1 and 3-5 and many variations and modifications are possible. That is, a person skilled in the art can realize various other embodiments without departing from the spirit and scope of the inventive idea by using a power supply device having other complicated or simple structure. For example, the input power source is not limited to the single-phase power source, but can be easily applied to a three-wire type three-phase power source or a four-wire type three-phase power source.

[0018]

As described above, according to the present invention, the output DC line of the converter becomes stable by using the tap of the tap inductance or the neutral point terminal. Furthermore,
It is possible to effectively reduce the adverse effect of electrical interference noise due to switching in the converter on the electromagnetic environment.
Furthermore, since the deterioration of the electromagnetic environment of the load is effectively reduced, a good electromagnetic environment can be obtained.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram showing a conventional example.

FIG. 3 is a circuit diagram showing a second embodiment of the present invention.

FIG. 4 is a circuit diagram showing a third embodiment of the present invention.

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

[Explanation of symbols]

 1,1DD converter 3 Load E, E0 power supply LT Inductance with center tap

Claims (7)

[Claims] 1. A power supply device for supplying electric power to a load, wherein a pair of power supply terminals, a tapped inductance connected in parallel between the pair of power supply terminals, and a pair of input terminals are the pair of power supply terminals. A converter connected to the converter, and first and second serially connected output sides of the converter
A power supply device, the connection point of the first capacitor and the second capacitor and the tap of the tapped inductance being connected. 2. A power supply device for supplying electric power to a load, comprising: a pair of power supply terminals, a neutral point terminal, a converter having a pair of input terminals connected to the pair of power supply terminals, and an output of the converter. First and second connected in series to the side
And a connection point between the first capacitor and the second capacitor and the neutral point terminal. 3. A power supply device for supplying power to a load, the power supply terminal, a tapped inductance connected in parallel between the power supply terminals, a converter connected to the power supply terminal, and an output of the converter. First and second connected in series to the side
And connecting a connection point between the first capacitor and the second capacitor and a tap of the tapped inductance, and a pair of power supply lines between the power supply terminal and the converter. A power supply device characterized in that an excessive current is suppressed from flowing between the connection point and the tap by inserting a reactor. 4. A power supply device for supplying electric power to a load, comprising: a pair of power supply terminals, a neutral point terminal, a converter connected to the power supply terminals, and a series connection on the output side of the converter. 1st and 2nd
And a connection point between the first capacitor and the second capacitor and the neutral point terminal, and the power supply terminal and the converter are connected via a pair of reactors. A power supply device characterized in that 5. The power supply device according to claim 3 or 4, wherein the converter includes a high-speed semiconductor switching element. 6. A power supply device according to claim 5, wherein the high-speed semiconductor switching element is an insulated gate type element. 7. The power supply device according to claim 6, wherein the insulated gate type device includes a MOSFET.