JPH037066A - Dc power source - Google Patents

Abstract

PURPOSE:To improve current waveform and power factor by forming a control pulse for turning a switching element from OFF state to ON state synchronously with a triangular wave and turning the switching element from ON state to OFF state synchronously with an output from a voltage comparator then providing the control pulse to the switching element. CONSTITUTION:A DC power source comprises a current detector 19 for detecting the current flowing through a switching element 15 or a reactor 13, a triangular wave generating circuit 26, a circuit 29 for forming a combined voltage of an output voltage from a differential signal forming circuit and the triangular wave, a voltage comparator 25 for comparing current waveform detected through the current detector 19 with a combined voltage outputted from the combining circuit 29 and the like, where a control pulse for turning the switching element 15 from OFF state to ON state synchronously with the triangular wave and turning the switching element 15 from ON state to OFF state synchronously with an output from the voltage comparator 25 is formed and fed to the switching element 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a DC power supply device that can easily improve the current waveform in an AC input line.

[Conventional technology]

In order to correct the distortion of the current waveform of the AC input line based on the on/off operation of switching elements such as switching regulators or inverters connected to the rectifier circuit,
A reactor is connected to the power supply line, and the switching element connected between the pair of DC output lines of the rectifier circuit is turned on and off.
It is known to perform off control (for example, Japanese Patent Application Laid-Open No. 1153
-190557).

[Problem to be solved by the invention]

By the way, in conventional devices, it is necessary to form a signal corresponding to the difference between the output voltage and the reference voltage and to multiply this signal by a reference sine wave, which inevitably leads to a complicated circuit configuration and high cost. Became.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a DC power supply device that can be manufactured at low cost.

[Means to solve the problem]

According to claim 1, the present invention provides an AC power terminal, a rectifier circuit connected to the AC power terminal, and an AC power line between the AC power terminal and the rectifier circuit. an inductance circuit element connected in series or in series and/or parallel to a DC output line between the rectifier circuit and the switching element; - In a DC power supply device having a switching element that is turned off and controls the storage and release of energy to the inductance circuit element, and a smoothing capacitor provided on the output side of the switching element, the smoothing capacitor performs smoothing. a voltage detection circuit for detecting the DC output voltage, a current detector for detecting the current flowing through the switching element or the reactor, a reference voltage source, a reference voltage of the reference voltage fE source, and the voltage detection circuit. a triangular wave generating circuit that generates a triangular wave at a sufficiently high frequency than the AC voltage of the AC power supply terminal, and the differential signal forming circuit a combining circuit that forms a combined voltage of the output voltage of the output voltage and the triangular wave;

a voltage comparator that generates a voltage comparison output between a current detection waveform obtained from the current detector and a composite voltage obtained from the synthesis circuit; and a voltage comparator that converts the switching element from an OFF state to an ON state in synchronization with the triangular wave; and a control pulse forming circuit that forms a control pulse for switching the switching element from an on state to an off state in synchronization with the output of the voltage comparator and supplies the control pulse to the switching element. It is something. Note that the inductance circuit element is, for example, a reactor or a transformer. Further, the difference signal forming circuit is, for example, the differential amplifier (error amplifier) 22 of the embodiment.

In the invention according to claim B, the composite value of the triangular wave and the current detection waveform is compared with the differential output, and in the invention according to claim 5, which features a control pulse, the slope of the triangular wave is controlled by the differential output.

In the invention according to claims 2, 4 and 6, the slope of the triangular wave is controlled based on the average value of the AC voltage.

[For production]

In any of the claimed inventions, the current waveform can be improved without using a reference sine wave and a multiplier.

Furthermore, the current waveform and power factor can be improved with a relatively simple circuit.

[First Embodiment] Next, a DC power supply device according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. This device has a pair of AC power supply terminals 1.2 to which a commercial AC power supply of, for example, 50 Hz is connected. The high frequency removal filter 3 connected to the power supply terminal 1.2 consists of an axle 4.5 connected in series with the line and a capacitor 6.7 connected between the pair of lines.

A full-wave rectifier circuit 8 is connected to the output stage of filter B. To one side of a pair of DC lines 11.12 between this rectifier circuit 8 and a pair of DC output terminals 9.10, a glue handle 13 and a reverse current blocking diode 14 as energy storage elements are connected in series. An FE is connected between the output terminal of the reactor 13 and the lower DC line 12.
A switching element 15 consisting of T force and a current detection resistor 16 as a current detector are connected. The smoothing capacitor 1C8 is connected between the output terminals 9 and 10 at the output stage of the reverse current blocking diode 14.

A voltage detection circuit 19 consisting of resistors 17 and 18 is connected to an output terminal 9.
．． This voltage detection line 20 is connected to one input terminal of a differential amplifier 22 of a switching element control circuit 21. A reference voltage source 23 is connected to the other input terminal of the differential amplifier 22.

A current detection line 24 led out from one end of the current detection resistor 16 is connected to one input terminal of a voltage comparator 25tv. The other input terminal of the voltage comparator 25 receives a triangular wave (sawtooth wave) from the triangular wave generating circuit 26.
A composite image wj29 consisting of resistors 27 and 28 for obtaining a composite waveform of the differential output of the differential amplifier 22 and the differential output of the differential amplifier 22 is connected.

Control pulse forming circuit 30 pieces, RS flip 70 pieces 31 pieces
, set signal generation circuit 32 and reset signal formation circuit 33
It consists of The set signal generating circuit 32 forms a set trigger signal in synchronization with the triangular wave of the triangular wave generating circuit 26, and applies this to the set terminal S of the 7-rip 70-g 61. In FIG. 1, the set signal generation circuit 62 is the triangular wave generation circuit 26.
However, the set signal generation circuit 32 has a built-in reference oscillator, and the set signal for the flip-flop 31 is formed based on the output clock of this reference oscillator, and the triangular wave generation circuit 26 is controlled. You may also do so. The reset signal forming circuit 63 applies a reset trigger pulse to the reset terminal R of the 7-lip-frog 31 in response to the change in the output state of the comparator 25. The Q output terminal of the 7-lip-frog 31 is connected to the control terminal of a switching element 150 consisting of an FET (gate terminal).

〔motion〕

Next, the operation of the circuit shown in FIG. 1 will be explained with reference to the waveforms shown in FIG. When a sinusoidal AC voltage is applied to the power supply terminals 1 and 2, a full-wave rectified voltage waveform shown in FIG. 2 is obtained at the output stage of the rectifier circuit 8. This voltage waveform is transferred to the switching element 15
When the voltage is switched on and off at a frequency sufficiently higher than the power supply frequency (several Hz or more, for example 20 kHz), the switching element 15 receives a current with a vibration corresponding to the amplitude of the voltage waveform, as shown in Figure 2 (■). As a result, the current waveform flowing through the power supply terminals 1.2 is as shown in Figure 2 (Q
As shown in , it becomes a Chikama sine wave corresponding to the voltage waveform.

Incidentally, it is desirable that the duty of the control pulse for controlling the switching element 15 to be on and off is small when the amplitude of the sine wave is large, and large when the amplitude is small, in order to bring the current waveform closer to a sine wave. Further, it is desirable to use the switching element 15 not only for improving the current waveform but also for output voltage control in order to simplify the circuit configuration. In order to achieve these, a current detection waveform is input to the comparator 25, and a composite wave of a triangular wave and a differential output is input to the comparator 25.

Since the reactor 13 is provided, the current flowing through it during the ON period of the switching element 15 increases with time as shown in FIG. 2 (8). Switching element 15
The energy accumulated in the haractuator 16 during the off period is transferred to a capacitor through the diode 14? Given on the 16th. At this time, since the capacitor H& is charged with the sum of the voltage of the reactor 16 and the power supply voltage, the charging voltage of the capacitor 16a becomes higher than the power supply voltage. The DC voltage shown in Figure 2 Ω obtained between the output terminals 9 and 10 is compared with the DC reference voltage of the reference voltage source 23, and the differential output voltage corresponding to the difference is obtained as shown in Figure 2 (Q). From the triangular wave generation circuit 26, as shown in FIG. 2 [F], a triangular wave [sawtooth wave] having a downward slope to the right is obtained at a high frequency (for example, 20 kHz).The triangular wave in FIG. 2 [F] is combined with the differential output of Q in FIG. The waveform shown by the dotted line at H) is compared with the sawtooth wave shown by the solid line in FIG. The reset trigger pulse shown in FIG. 2(I) is obtained.The set trigger pulse BEj is generated from the set signal generation circuit 32 in synchronization with the rising edge of the triangular wave as shown in FIG. K7i: Since the current detection waveform of the switching element 15 whose peak value changes is input, the duty of the control pulse of the switching element 15 becomes small during the period when the amplitude of the AC voltage is large, and conversely, the duty of the control pulse of the switching element 15 becomes small when the amplitude of the AC voltage is small. The duty of the pulse increases. Also, the duty of the control pulse changes inversely proportional to the output voltage.

As described above, according to this embodiment, the input current waveform and power factor can be improved by nth degree without using one multiplier.

[Second Embodiment] Next, a DC power supply device according to a second embodiment will be described with reference to FIGS. 3 and 4. However, in FIGS. 6 and 4 and later shown in FIGS. 5 to 14, substantially the same parts as in FIGS. 1 and 2 are designated by the same reference numerals, and their explanations will be omitted.

In the circuit of figure M3, the fourth wave obtained from the triangular wave generating circuit 26
In order to synthesize the triangular wave with an upward slope to the right in the figure [F] and the current detection waveform in FIG.
This output line is connected to a comparator 25.

A waveform shown in principle in FIG. 40 is obtained from the synthesis circuit 29, and this waveform is compared with the differential output of FIG. When reaching the level of , the output of the comparator 25 switches.

The reset pulse shown in FIG. 4(I) is generated from the reset signal forming circuit 36. This also makes it possible to obtain the same effects as in the first embodiment.

[Third Embodiment] In the embodiment shown in FIGS. 5 and 6, the comparator 25
A current detection line 24 and a triangular wave generation circuit 26 are connected to each other, and an output terminal of the differential amplifier 22 is connected to a slope control terminal of the triangular wave generation circuit 26. The triangular wave generating circuit 26 outputs a triangular wave having a slope opposite to that of the current detection waveform shown in ) in FIG. 6, as shown in the FIG. 6 side. As a result, the output of the comparator 25 changes according to the same principle as in FIG.

At the intersection of the triangular wave shown by the solid line in FIG. 6 [F] and the current detection waveform shown by the dotted line, the reset pulse shown in FIG. 6 0 is generated, and the control pulse shown in FIG. It will be done.

Duty control based on output voltage changes is violated in triangular wave slope control. If the load becomes light and the output voltage increases after time 11 in Figure 6, the slope of the triangular wave will become gentler, the @ of the control pulse shown in Figure 6 (1) will become narrower, and the output voltage will rise to the reference value. will be returned to.

This sixth embodiment also provides the same effects as the first embodiment.

[Fourth Embodiment] The DC power supply device of the fourth embodiment shown in FIG. 7 is obtained by adding a circuit for changing the slope of the triangular wave depending on the input voltage to the circuit of FIG. 1. That is, a capacitor 42 is connected between point A of the output line 11 of the rectifier circuit 8 and the ground via a diode 41, a voltage dividing circuit of resistors 43 and 44 is provided in parallel with the capacitor 42, and the voltage division is determined. The signal is configured to be applied to the triangular wave generating circuit 26. capacitor 4
2 smooths the full-wave rectified waveform, so an average value of the AC voltage is obtained, and thereby the slope of the triangular wave is controlled in the same way as in the sixth embodiment. According to this fourth embodiment, in addition to obtaining the same effects as the embodiment of Ml, it is also possible to obtain the effect of reducing fluctuations in the waveform of the long current and the power factor due to fluctuations in the input voltage.

[Modified example]

The invention is not limited to the embodiments described above.

For example, the following transformations are possible.

fil Even when the triangular wave and the current detection waveform are combined and input to the comparator 25 as shown in Fig. 8, the slope of the triangular wave can be controlled by the average value of the input voltage as in Fig. 7. good. That is, the triangular wave slope control circuit shown in FIG. 7 may be added to the circuit shown in FIG. 3.

+21 As shown in FIG. 9, the slope of the triangular wave may be controlled by both the output of the differential amplifier 22 and the average value of the input voltage. That is, the triangular wave slope control circuit shown in FIG. 7 may be added to the circuit shown in FIG. 5.

(3) As shown in FIG. 10, the reactor 13 may be connected to the AC input line of the rectifier circuit 8.

(4) As shown in FIG. 11, a transformer primary winding fm13a and a secondary winding 1s13b are provided in place of the reactor 13, and the switching element 15 is connected in series to the first-order best #13a.
Connect the energy stored in the transformer to the secondary winding #
5 may be configured to emit at 13b.

[5) As shown in FIG. 12, the switching element 15 is connected in series to the line 11, and the reactor 13 is connected to the line 1.
It may be connected between 1.12.

(6) As shown in FIG. 13, the transformer primary winding m 13 a and the secondary winding 13 b serve as inductance elements.
They may be insulated and separated.

(7) As shown in FIG. 14, in addition to the diode 14, a smoothing circuit consisting of a diode 51 and a reactor 52 may be provided at the output stage of the second-best a15b as an inductance element. Note that the voltage conversion circuit using the switching element 15 can be further modified in various ways.

(8) When the output voltage is low, the voltage detection line 20 may be directly connected to the output terminal 9 without using the voltage dividing circuit of the resistors 77 and 18.

〔Effect of the invention〕

As is clear from the above description, the input current waveform and power factor can be improved without using a single multiplier according to any of the claimed inventions.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a DC power supply device according to a first embodiment of the present invention, and FIG. 6 is a circuit diagram showing a DC power supply device according to a second embodiment of the present invention. Cycle 6--triangular wave generation circuit (J) Fig. 6 (1) Fig. 8 Fig. 9 Fig. 11 Fig. 12 D) L--11--11--

Claims (1)

[Scope of Claims] [1] An AC power terminal, a rectifier circuit connected to the AC power terminal, and a circuit connected in series with an AC power line between the AC power terminal and the rectifier circuit, or in series with the AC power line between the AC power terminal and the rectifier circuit. an inductance circuit element connected in series and/or in parallel to a DC output line between the switching element and the inductance circuit, which operates on and off with a cycle shorter than the cycle of the AC voltage of the AC power supply terminal; In a DC power supply device having a switching element that controls storage and release of energy with respect to an element, and a smoothing capacitor provided on an output side of the switching element, detecting a DC output voltage smoothed by the smoothing capacitor. a voltage detection circuit; a current detector for detecting the current flowing through the switching element or the reactor; a reference voltage source; a differential signal forming circuit that forms a corresponding voltage; a triangular wave generating circuit that generates a triangular wave at a frequency sufficiently higher than the AC voltage of the AC power supply terminal; and a composite voltage of the output voltage of the differential signal forming circuit and the triangular wave. a voltage comparator that generates a voltage comparison output between the current detection waveform obtained from the current detector and the composite voltage obtained from the synthesis circuit; and a voltage comparator that turns off the switching element in synchronization with the triangular wave. and a control pulse forming circuit that forms a control pulse to convert the switching element from the on state to the off state in synchronization with the output of the voltage comparator, and supplies the control pulse to the switching element. DC power supply equipment. [2] The DC power supply device according to claim 1, further comprising a circuit that controls the slope of the triangular wave based on the average value of the AC voltage. [3] An AC power terminal, a rectifier circuit connected to the AC power terminal, and a circuit connected in series to the AC power line between the AC power terminal and the rectifier circuit or between the rectifier circuit and the switching element. an inductance circuit element connected in series and/or parallel to the DC output line, which operates on and off with a cycle shorter than the cycle of the AC voltage at the AC power supply terminal, and stores energy in the inductance circuit element and A DC power supply device including a switching element that controls emission and a smoothing capacitor provided on the output side of the switching element, comprising: a voltage detection circuit that detects the DC output voltage smoothed by the smoothing capacitor; a current detector for detecting a current flowing through the switching element or the reactor; a reference voltage source; and forming a voltage corresponding to a difference between a reference voltage of the reference voltage source and a detected voltage obtained from the voltage detection circuit. a difference signal forming circuit; a triangular wave generating circuit that generates a triangular wave at a frequency sufficiently higher than the AC voltage of the AC power supply terminal; and a synthesis circuit that forms a composite voltage of the current detection waveform obtained from the current detector and the triangular wave. a voltage comparator that generates a voltage comparison output between a difference signal obtained from the difference signal forming circuit and a composite voltage obtained from the synthesis circuit; and a voltage comparator that changes the switching element from an off state to an on state in synchronization with the triangular wave. and a control pulse forming circuit that forms a control pulse that converts the switching element from an on state to an off state in synchronization with the output of the voltage comparator and supplies it to the switching element. Device. [4] The DC power supply device according to claim 5, further comprising a circuit that controls the slope of the triangular wave based on the average value of the AC voltage. [5] An AC power terminal, a rectifier circuit connected to the AC power terminal, and a circuit connected in series to the AC power line between the AC power terminal and the rectifier circuit or between the rectifier circuit and the switching element. an inductance circuit element connected in series and/or parallel to the DC output line, which operates on and off with a cycle shorter than the cycle of the AC voltage at the AC power supply terminal, and stores energy in the inductance circuit element and A DC power supply device including a switching element that controls emission and a smoothing capacitor provided on the output side of the switching element, comprising: a voltage detection circuit that detects the DC output voltage smoothed by the smoothing capacitor; a current detector for detecting a current flowing through the switching element or the reactor; a reference voltage source; and forming a voltage corresponding to a difference between a reference voltage of the reference voltage source and a detected voltage obtained from the voltage detection circuit. a difference signal forming circuit, which generates a triangular wave at a frequency sufficiently higher than the AC voltage of the AC power supply terminal, and is formed so that the slope of the triangular wave changes in response to the output of the difference signal forming circuit. a voltage comparator that generates a voltage comparison output between the triangular wave obtained from the triangular wave generating circuit and a current detection waveform obtained from the current detector; and a control pulse forming circuit for forming and applying to the switching element a control pulse that causes the switching element to change from the off state to the on state and from the on state to the off state in synchronization with the output of the voltage comparator. A DC power supply device featuring: [6] The DC power supply device according to claim 5, further comprising a circuit that controls the slope of the triangular wave based on the average value of the AC voltage.