JP2683839B2 - Power supply - Google Patents

Description

The present invention relates to a power supply device having an auxiliary power supply composed of a storage battery or a capacitor.

[Problems to be Solved by Prior Art and Invention] A step-up converter in which a rectifier circuit is connected to an AC power source, an output stage of this rectifier circuit is connected via a reactor, and a smoothing circuit is connected to an output stage of a switch. Is known.

Further, a method of connecting a rectifier circuit and a reactor between an AC power source and an inverter, and intermittently short-circuiting DC lines by using a conversion switch of the inverter to store energy in the reactor is disclosed in, for example, Japanese Patent Application Laid-Open It is disclosed in Japanese Patent Application Laid-Open No. 63-190557 (Japanese Patent Application No. 62-19453).

When a switch in a converter of this type or a conversion switch of an inverter is controlled to be turned on and off at a high frequency, the sine wave voltage is interrupted, and as a result, the input current becomes an approximate sine wave. Also, the power factor becomes almost 1.

In this type of converter, a smoothing capacitor for smoothing the rectified output obtained from the rectifier circuit is not provided. Moreover, the storage battery charged by the output of the rectifier circuit cannot be connected as a standby power source. Therefore, when the AC power supply fails or a voltage drop occurs, the power supply is continued for a very short time only by the output smoothing capacitor.

Further, in a conventional general converter, a DC power supply may be provided with a large-capacity capacitor or a storage battery as a backup power supply. However, if the voltage of the capacitor or the storage battery drops, it becomes impossible to obtain a desired output voltage, and eventually the capacity of the capacitor or the storage battery cannot be effectively used.

Then, the objective of this invention is providing the power supply device which can utilize the capacity of a capacitor or a storage battery effectively.

[Means for Solving the Problems] The present invention for achieving the above object includes an AC power supply terminal, a rectifier circuit connected to the AC power supply terminal, and one output terminal and the other output terminal of the rectifier circuit. A main switch connected between the main switch and the main switch, a reactor connected in series to the power supply line between the rectifier circuit and the main switch, and a smoothing connected in parallel to the main switch via a rectifying diode. Capacitor, a main switch control circuit that controls ON / OFF of the main switch so that the voltage of the smoothing capacitor has a constant value, and one output terminal of the rectifier circuit and the other of the other of the main switch control circuit on the input side of the reactor. An auxiliary power source consisting of a capacitor or a storage battery connected to an output terminal or between a pair of input terminals of the rectifier circuit via an auxiliary switch, A charging circuit for charging the auxiliary power supply based on the voltage on the output side, and when the AC voltage of the AC power supply terminal becomes zero or a low value or when the voltage on the output side of the smoothing capacitor drops. The present invention relates to a power supply device characterized by comprising an auxiliary switch control circuit for turning on the auxiliary switch.

As described in claim 2, it is preferable that the voltage (output voltage) of the smoothing capacitor is set to a predetermined value and the main switch is controlled so that the current of the AC power supply terminal is approximated to an input waveform or a sine wave. .

Further, as described in claim 3, it is desirable to replace the main switch of claim 1 with an inverter.

Further, as described in claim 4, a rectifying / smoothing circuit can be connected to the output stage of the inverter.

Further, as described in claim 5, it is desirable to control the inverter so that the current of the AC power supply terminal is approximated to an input waveform or a sine wave and a desired output voltage is obtained.

Further, as shown in claims 6 and 7, claims 1 and 3
The rectifier circuit can be replaced with a DC power supply that supplies a flat voltage.

[Operation] According to the invention of each claim, the voltage of the auxiliary power supply is level-converted (controlled) by the reactor and the main switch. Therefore, even if the voltage of the auxiliary power supply drops, it can be increased by the boosting action of the reactor. Therefore, a desired output voltage can be obtained in a wide range of the auxiliary power supply voltage from a high value to a low value. In short, the capacity of the auxiliary power supply can be effectively used.

[First Embodiment] Next, a power supply device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. A full-wave rectifier circuit 3 including four bridge-connected diodes D1, D2, D3, and D4 is connected to power supply terminals 1 and 2 for supplying, for example, a commercial AC voltage of 50 Hz in FIG.

A main switch 9 is connected via a reactor 8 between a pair of power supply lines 6 and 7 connected to a pair of output terminals 4 and 5 of the rectifier circuit 3. The main switch 9 is composed of an N-channel insulated gate type field effect transistor in which the source is connected to the substrate and has a built-in diode.

A smoothing capacitor 11 is connected in parallel to the main switch 9 via a rectifying diode 10. A load 14 is placed between the pair of output terminals 12 and 13 connected to the smoothing capacitor 11.
Is connected.

The main switch control circuit 15 connected to the control terminal (gate) of the main switch 9 supplies an on / off control signal to the main switch 9. The control circuit 15 includes an output voltage detection circuit 16 connected to the output terminals 12 and 13, a current detector 17 connected to the input line of the rectifier circuit 3, and an input connected to the AC power supply terminals 1 and 2. The voltage detection circuits 18 are connected to each other.

19 is a capacitor for auxiliary power supply, and is an auxiliary switch 20
Is connected between the output power supply lines 6 and 7 of the rectifier circuit 3 via. As a charging circuit for the auxiliary power supply capacitor 19, a charging resistor 21 is connected between the output terminal 12 and one end of the auxiliary power supply capacitor 19.

The auxiliary switch 20 is composed of a thyristor, and an auxiliary switch control circuit 22 is connected to this gate (control terminal). The auxiliary switch control circuit 22 includes a power failure or voltage drop detection circuit connected to the power supply terminals 1 and 2, and turns on the auxiliary switch 20 when a power failure or voltage drop is detected. FIG. 2 shows the main switch control circuit 15 in detail.
The output line of the current detector 17 is connected to one input terminal (inverting input terminal) of the first error amplifier 24 via the first full-wave rectifier circuit 23. The output line of the input voltage detection circuit 18 is connected to the other input terminal (non-inverting input terminal) of the first error amplifier 24 via the second full-wave rectifier circuit 25 and the coefficient circuit, that is, the multiplier 26. . The first error amplifier 24 produces an output corresponding to the difference between the current containing the ripple component and the sinusoidal voltage.

In order to control the main switch 9 so as to keep the output voltage constant, the output line of the output voltage detection circuit 16 is connected to one input terminal (inverting input) of the second error amplifier 27. The reference voltage source 28 is connected to the other input terminal (inverting input). The second error amplifier 27 generates an output voltage corresponding to the difference between the detected voltage and the reference voltage,
Send to the multiplier 26. The multiplier 26 adds the second error amplifier 27 to the amplitude of the reference sine wave waveform supplied from the second full-wave rectification circuit 25.
The value obtained by multiplying the output of is applied to the non-inverting input terminal of the first error amplifier 24.

One input terminal of the voltage comparator 29 is a low-pass filter 30.
Is connected to the output terminal of the first error amplifier 24, and the other input terminal is connected to the sawtooth wave generation circuit 31. The output terminal of the comparator 29 is connected to the main switch 9.

[Operation] Next, the operation of the circuit shown in FIG. 1 will be described.

In the circuit of FIG. 1, a capacitor for smoothing the full-wave rectified waveform of the AC power supply voltage of 50 Hz is not connected between the output lines 6 and 7 of the rectifier circuit 3. At the output stage of the main switch 9, a sum voltage of the sine wave rectified output voltage corresponding to the sine wave AC power supply voltage of the input terminals 1 and 2 and the voltage based on the energy stored in the reactor 8 can be obtained.

When the main switch 9 is on / off controlled, the rectifier circuit 3
The currents on the input side and the output side of are also changed following this.
Since the on / off frequency of the main switch 9 is, for example, 50 Hz, which is sufficiently higher than the power supply frequency (50 Hz) of the input terminals 1 and 2, even if the sine wave voltage is interrupted by the main switch 9,
The current flowing through the reactor 8 and the corresponding AC input current become an approximate sine wave including ripple without interruption. That is, as shown in FIG. 3 (A), the error signal A1 obtained through the low pass filter 30 and the sawtooth wave signal A2 are compared by the comparator 29, and the output of the comparator 29 shown in FIG. 3 (B) is used. When the main switch 9 is on / off controlled,
An approximate sine wave current detection signal F1 including ripple shown in FIG. 3 (C) is obtained.

When the current detection signal F1 is input to one input terminal of the error amplifier 24 and the reference sine wave F2 shown in FIG. 3 (C) is input from the multiplier 26 to the other input terminal, it is connected to the output terminal of the error amplifier 24. A signal A1 including the information of the input current and the information of the output voltage is obtained at the output stage of the low-pass filter 30. The width of the comparison output pulse of the signal A1 and the sawtooth wave A2 changes according to the change of the output voltage. Control is thus achieved to keep the output voltage constant.

The main switch 9 is turned on during the periods t1 to t2, t3 to t4, and t5 to t6, and the current detection signal F1 gradually increases. The current detection signal F1 gradually decreases during the periods t2 to t3 and t4 to t5 when the main switch 9 is turned off.

The smoothing capacitor 11 is charged to a value higher than the peak value of the output voltage of the rectifier circuit 3 by the voltage of the reactor 8. Further, the auxiliary power supply capacitor 19 is also charged via the resistor 21 and, like the smoothing capacitor 11, is charged to a value higher than the peak value of the rectified voltage.

When the voltage of the AC power supply terminals 1 and 2 becomes zero or a value lower than a predetermined value due to a power failure or the like, this is detected by the auxiliary switch control circuit 22 and the auxiliary switch 20 is turned on. As a result, the power supply from the auxiliary power supply capacitor 19 instead of the rectifier circuit 3 starts. Even if the voltage of the auxiliary power supply capacitor 19 drops, the output voltage can be obtained by boosting by the boosting action of the reactor 8. Therefore, the energy of the auxiliary power supply capacitor 19 can be used effectively and the power supply time during a power failure can be extended. can do.

[Second Embodiment] Next, a power supply device according to a second embodiment shown in FIG. 4 will be described. However, in FIG. 4 and later-described FIGS. 5 to 13, parts that are substantially the same as those in FIGS. 1 to 3 are given the same reference numerals, and description thereof will be omitted.

The circuit shown in FIG. 4 is obtained by adding a charging diode 41 and a peak value holding capacitor 42 to the circuit shown in FIG.
The anode of the diode 41 is connected to the output terminal of the reactor 8. Therefore, the voltage before smoothing is the diode
It is rectified by 41, its peak value is first charged in the capacitor 42, and then the charge of the capacitor 42 is transferred to the capacitor 19 via the resistor 21.

Even with such a configuration, it is possible to obtain the same effects as those of the embodiment.

[Third Embodiment] In a third embodiment shown in FIG. 5, an inverter 51 is connected to the rectifier circuit 3 via a reactor 8 instead of the main switch 9 of the first and second embodiments. The inverter 51 comprises bridge-connected first, second, third and fourth conversion switches Q1, Q2, Q3, Q4 and an output transformer 52. The primary winding 53 of the output transformer 52 has a connection point between the first and second conversion switches Q1 and Q2 and a third and fourth conversion switch Q.
It is connected between the 3 and Q4 connection points. The secondary winding 54 is formed at a center tap and is connected to a rectifying / smoothing circuit 58 including diodes 55 and 56 and a capacitor 57.

The inverter control circuit 15a is almost the same as the main switch control circuit 15 shown in FIG. 2 and is configured as shown in FIG. As is clear from the comparison between FIGS. 2 and 6, a control signal forming circuit 59 for the first to fourth conversion switches Q1 to Q4 is added.

The control signal forming circuit 59 comprises, for example, as shown in FIG. 8, a square wave generating circuit 62, a NOT circuit 61, a trigger pulse generating circuit 62, and a trigger type flip-flop 63. The square wave generating circuit 60 generates a fixed square wave pulse for ON / OFF controlling the first switch Q1 shown in FIG. 7 (B). The NOT circuit 61 is connected to the square wave generating circuit 60 and generates a square wave for controlling the switch Q3 of FIG. 3 shown in FIG. 7 (C). The square wave generation circuit 60 is also connected to the sawtooth wave generation circuit 31. The sawtooth wave generation circuit 31
The sawtooth wave A2 shown in FIG. 7 (A) is generated in synchronization with the square wave of FIG. 7 (B). That is, the sawtooth wave generating circuit 31 generates the sawtooth wave A2 in response to the leading edge and the trailing edge of the pulse shown in FIG. 7 (B).

The comparator 29 uses the signal A1 and the sawtooth wave shown in FIG.
The comparison output shown in FIG. 9 (A) is generated based on the comparison with A2. Trigger pulse generation circuit 62 connected to comparator 29
Generates the trigger pulse shown in FIG. 9 (B) in response to the leading edge of the comparison output pulse shown in FIG. 9 (A).

Each time the trigger pulse of the trigger pulse generation circuit 62 is input to the trigger input terminal T of the trigger type flip-flop 63, the state of the output terminal changes, and the switch control shown in FIG. 9 (C) is performed. A signal is applied from the non-inverting output terminal to the second switch Q2, and a switch control signal shown in FIG. 9 (D) is applied from the inverting output terminal to the fourth switch Q4.
The pulses in FIGS. 9C and 9D are the same as the pulses in FIGS. 7D and 7E.

The control signal forming circuit 59 is not limited to that shown in FIG. 8, but can be modified in various ways, and can be constituted by a logic gate circuit, for example.

As shown in FIG. 7 (A), the comparator 29 compares the signal A1 with the sawtooth wave A2, and based on this, FIG. 7 (B)-
(E) forms the switch control signal, and the conversion switch Q1
When Q4 is turned on and off, t0 to t1, t2 to t3, t4 to t5
During the period, the power supply lines on the output side of the reactor 8, that is, the input terminals of the inverter are short-circuited. Therefore, energy is accumulated in the reactor 8 during this period. t1-t2,
During the period from t3 to t4, etc., normal inverter operation is performed,
As shown in FIG. 7 (G), an AC voltage having a frequency sufficiently higher than the commercial voltage can be obtained from the transformer 52.

The current detection signal F1 is compared with the reference sine wave signal F2 as shown in FIG. 7 (F) and controlled so as to follow this. Therefore, the currents of the power supply terminals 1 and 2 have an approximate sine wave, and the power factor is about 1. The principle of output voltage control in the inverter 51 is the same as that of the first embodiment.

In this embodiment, the input terminal of the inverter 51 is connected to the peak charging capacitor 42 via the diode 41. Therefore, the capacitor 42 is charged to the peak value of the voltage boosted by the reactor 8, and this charge is transferred to the auxiliary power supply capacitor 19. As a result, the same effects as those of the first embodiment can be obtained by the second embodiment.

[Fourth Embodiment] Next, a power supply device according to a fourth embodiment will be described with reference to FIG. In this embodiment, a parallel inverter 51a is connected between the output line of the reactor 8 and the power supply line 7. The inverter 51a includes first and second conversion switches Q1 and Q2 and a center tap type transformer 52. The center tap of the primary winding 53 of the transformer 52 is connected to the output terminal of the reactor 8, and the first and second conversion switches Q1 and Q2 are provided between both ends of the primary winding 53 and the power supply line 7.
Are connected respectively.

When operating this power supply device, first, the control circuit 15
Based on b, the first and second conversion switches Q1 and Q2 are simultaneously turned on. As a result, energy is stored in the reactor 8 as in FIG. Next, the first conversion switch Q1 is turned on and the second conversion switch Q2 is turned off. As a result, a voltage obtained by adding the voltage of the reactor 8 to the power supply voltage is applied to the upper half of the primary winding 53, and a voltage corresponding to this is obtained in the secondary winding 54. Then, the first and second conversion switches Q1 and Q2 are simultaneously turned on again to accumulate energy in the reactor 8. Next, the second conversion switch Q2 is controlled to be turned on and the first conversion switch Q1 is controlled to be turned off. As a result, a voltage obtained by adding the voltage of the reactor 8 to the power supply voltage is applied to the lower half of the primary winding 53, and a voltage in the opposite direction to the previous direction is obtained at the secondary winding 54.

The first principle is to control the output voltage and improve the input current waveform.
~ The same as the third embodiment. Therefore, the same effects as those of the first to third embodiments can be obtained by the fourth embodiment.

[Fifth Embodiment] A power supply device according to a fifth embodiment shown in FIG.
51b is a main switch Q for conversion, a capacitor C and a transformer 52
It is composed of While the main switch Q is on-controlled by the control circuit 15c, energy is accumulated in the reactor 8 and at the same time, a discharge circuit for the capacitor C is formed and a current flowing from the bottom to the top of the primary winding 53 is increased. Flowing. While the main switch Q is off, a current consisting of the reactor 8, the capacitor C, and the primary winding 53 flows from the top to the bottom of the primary winding 53.

The capacitor 42 is connected to the tertiary winding 70 provided in the transformer 52 via the diode 41. Since the transformer 52 can obtain a constant voltage, the capacitor 42 and
19 is charged with a constant voltage.

The same working effects as those of the first to fourth embodiments can also be obtained by the fifth embodiment.

[Sixth Embodiment] A power supply device of FIG. 12 showing a sixth embodiment is obtained by omitting the waveform improving portion of the input current from the circuit of FIG. In this case, since the input waveform is not improved, the smoothing capacitor Cf is connected to the output stage of the rectifier circuit 3. Therefore, the DC voltage smoothed by the main switch 9 is interrupted. The auxiliary power supply capacitor 19 of this embodiment is
It has the same effects as those of the fifth embodiment. The electric charge of the smoothing capacitor Cf is also used at the time of power failure.

[Seventh Embodiment] A power supply device according to a seventh embodiment of FIG. 13 is obtained by removing the input current waveform improving portion from the circuit of FIG. In this embodiment, since the smoothing capacitor Cf is connected between the output lines 6 and 7 of the rectifier circuit 3, the inverter 51 is driven by the smoothed voltage. This embodiment also has the same effects as those in FIG.

[Modifications] The present invention is not limited to the above-described embodiment, and for example, the following modifications are possible.

(1) In each embodiment, the control circuit 22 may detect a power failure or a voltage drop by the output voltage of the rectifier circuit 3, the output voltage of the smoothing capacitors 11 and 57, or the output voltage of the inverter.

(2) The current detector 17 may be provided in the output line 6 or 7 of the rectifier circuit 3. Further, in the case of FIG. 5, the switch
The input current may be indirectly detected based on the currents of Q1 to Q4.

(2) In FIG. 1, a diode may be connected in series with the resistor 21.

(3) In FIG. 5, FIG. 10, and FIG. 13, the transformer 52
A tertiary winding is installed on the
You may make it charge 9 and 42.

(4) The capacitor 19 can be replaced with a storage battery.

(5) The chopper circuit or the inverter circuit in the latter stage of the reactor 8 can be variously modified.

(6) A high frequency removing filter can be connected between the power supply terminals 1 and 2 and the rectifier circuit 3.

(7) The capacitor Cf can be connected between the pair of input terminals of the rectifier circuit 3.

[Effects of the Invention] In the inventions of each claim of the present application, the capacitor or the storage battery of the auxiliary power supply is charged to a relatively high voltage by the boosted voltage obtained at the output side of the reactor, and the voltage of the auxiliary power supply is maintained during a power failure. Is boosted and supplied to the load. Therefore, the capacity of the capacitor of the auxiliary power source or the capacity of the storage battery can be effectively used, and the power failure compensation time by the auxiliary power source can be lengthened.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a power supply device according to a first embodiment of the present invention, FIG. 2 is a block diagram showing a main switch control circuit of FIG. 1, and FIG. 3 shows states of respective parts of FIG. Waveform diagram, FIG. 4 is a circuit diagram showing a power supply device according to a second embodiment of the present invention, FIG. 5 is a circuit diagram showing a power supply device according to a third embodiment of the present invention, and FIG. 6 is FIG. 7 is a block diagram showing the inverter control circuit of FIG. 7, FIG. 7 is a waveform diagram showing the state of each part of FIGS. 5 and 6, FIG. 8 is a block diagram showing the control signal forming circuit of FIG. 6, and FIG. FIG. 8 is a waveform diagram showing the state of each part, FIG. 10, FIG. 11, FIG. 12 and FIG. 13 are fourth, fifth and sixth.
9A and 9B are circuit diagrams showing a seventh embodiment and a seventh embodiment, respectively. 1, 2 ...... Power supply terminal, 3 ...... Rectifier circuit, 8 ...... Reactor, 9 ...... Main switch, 15 ...... Main switch control circuit, 19
...... Auxiliary power supply capacitor, 20 ... Auxiliary switch, 22 ...
… Auxiliary switch control circuit.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H02M 3/335 H02M 3/335 E 7/217 8726-5H 7/217

Claims (7)

(57) [Claims] 1. An AC power supply terminal, a rectifier circuit connected to the AC power supply terminal, a main switch connected between one output terminal and the other output terminal of the rectifier circuit, and the rectifier circuit. A reactor connected in series to a power supply line between the main switch, a smoothing capacitor connected in parallel to the main switch via a rectifying diode, and a voltage of the smoothing capacitor has a constant value. A main switch control circuit for ON / OFF controlling the main switch, between one output terminal and the other output terminal of the rectifier circuit on the input side of the reactor, or between a pair of input terminals of the rectifier circuit. An auxiliary power source composed of a capacitor or a storage battery connected via an auxiliary switch, and for charging the auxiliary power source based on the voltage on the output side of the reactor. Charging circuit, and an auxiliary switch control circuit for turning on the auxiliary switch when the AC voltage of the AC power supply terminal becomes zero or a low value or when the voltage on the output side of the smoothing capacitor decreases. Power supply device characterized by being. 2. The main switch control circuit controls the main switch so that the voltage of the smoothing capacitor is set to a desired value and the current of the AC power supply terminal is approximated to an input voltage waveform or a sine wave. The power supply device according to claim 1, wherein the power supply device is a circuit that is turned on / off at a cycle sufficiently shorter than the cycle. 3. An AC power supply terminal, a rectifier circuit connected to the AC power supply terminal, a reactor serially connected to an output side line of the rectifier circuit, and a rectifier circuit connected via the reactor, An inverter including a conversion switch that is turned on and off, and the conversion switch of the inverter is controlled so that the output voltage of the inverter has a constant value, and the reactor is provided between a pair of output terminals of the rectification circuit. An inverter control circuit for controlling the conversion switch so as to have a period of being short-circuited by the conversion switch via, and one output terminal and the other output terminal of the rectifier circuit on the input side of the reactor. And an auxiliary power source consisting of a capacitor or a storage battery connected via an auxiliary switch between a pair of input terminals of the rectifier circuit, A charging circuit for charging the auxiliary power supply based on the voltage on the output side of the reactor, and when the AC voltage of the AC power supply terminal becomes zero or low value or the voltage on the output side of the inverter has dropped. A power supply device comprising an auxiliary switch control circuit for controlling ON of the auxiliary switch at times. 4. The power supply device according to claim 3, further comprising a rectifying / smoothing circuit connected to the inverter. 5. The inverter control circuit intermittently connects between a pair of DC input lines of the inverter by the conversion switch so as to approximate a current flowing through the AC power supply terminal to an input voltage waveform or a sine wave. The power supply device according to claim 4, which is a circuit that short-circuits and controls the conversion switch so that the output voltage of the rectifying and smoothing circuit becomes constant. 6. A DC power supply, a main switch connected between one end and the other end of the DC power supply, and a reactor connected in series to a power supply line between the DC power supply and the main switch. A smoothing capacitor connected in parallel to the main switch via a rectifying diode; a main switch control circuit that controls ON / OFF of the main switch so that the voltage of the smoothing capacitor becomes constant; An auxiliary power supply consisting of a capacitor or a storage battery connected via an auxiliary switch between power lines on the input side of the reactor, and a charging circuit for charging the auxiliary power supply based on the voltage on the output side of the reactor, Auxiliary control for turning on the auxiliary switch when the voltage of the DC power source becomes zero or low or when the voltage on the output side of the smoothing capacitor decreases. A power supply device comprising: a switch control circuit. 7. A DC power supply, an inverter connected to the DC power supply via a reactor, a conversion switch of the inverter being controlled so that an output voltage of the inverter is constant, and a pair of the DC power supplies. An inverter control circuit for controlling the conversion switch so as to have a period in which the output terminals are short-circuited by the conversion switch via the reactor, and an auxiliary switch between the power supply lines on the input side of the reactor. Auxiliary power supply consisting of a connected capacitor or storage battery, a charging circuit for charging the auxiliary power supply based on the voltage on the output side of the reactor, when the voltage of the DC power supply becomes zero or low value, or An auxiliary switch control circuit that turns on the auxiliary switch when the voltage on the output side of the inverter drops. Location.