JPS5914021A - Rectified power supply circuit - Google Patents

Abstract

PURPOSE:To improve an input power-factor and to reduce switching loss by discharging electromagnetic energy accumulated in inductance when a switching element is turned on to a smoothing capacitor when the switching element is turned off. CONSTITUTION:Current IQ1 flowing into a transistor (TR) Q1 is chopped by the chopper operation of the TR Q1 and flows into a capacitor C0 as charging current through the secondary winding of a transformer T1. Consequently, current ID1 flowing into a diode D1 is reduced and the peak current of the current ID1 can be suppressed. Since current ID is synthesized current of the current ID1 and IQ1 and input current IS is removed of its high frequency component by a filter circuit 7, the input power-factor is increased. In addition, the charging current to the capacitor C0 is the synthesized current of the current ID1 and IQ1, so that chopper current IQ1 can be set to lower than the ordinary level and the switching loss of the TR Q1 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rectifier power supply circuit used in a discharge lamp lighting circuit.

FIG. 1 shows a basic circuit of a conventional example. Commercial power supply, (2
) is a full-wave rectifier circuit consisting of four diodes, which rectifies the commercial power supply (1) into direct current. Co is a smoothing capacitor connected in parallel to the output end of the rectifier circuit (2), and (3) is a load circuit. Figure 1 (a
) In the steady state of the circuit shown in FIG. 1(b), a pulsed input current Is flows from the commercial power supply +1) as shown in FIG. 1(b). Note that Vs is the power supply voltage of the commercial power supply. Here, the power supply power factor of this circuit is expressed by the following equation, assuming that the input voltage is not distorted.

However, 11 is the fundamental waveform component when the input current I8 is expanded into a series. In is the n-th harmonic component when the input current Is is expanded into a series, and Da is the fundamental wave component I when the input current Is is expanded into a series, and the input voltage of the input power supply (commercial power supply f4)
This is the phase difference with the fundamental wave component of the power supply voltage (Vs).

The power factors p and f of the circuit shown in Figure 1(a) are determined in a narrow manner, with little influence on the phase difference between the basic components of current and voltage. flow,]
'In the input type power supply circuit, the power supply power factor p, f
This has disadvantages such as a poor input current Is and an increase in the effective value of the input current Is.

Figure 2 shows another conventional example, in which a high frequency blocking filter circuit (7) is connected between the commercial power supply fli and the rectifier circuit (2).
is inserted, and the output terminal of the rectifier circuit (2) is connected to a smoothing circuit (8) and a smoothing circuit (JSCo) via a choke Lo serving as an interface. (3) is a load circuit. The switching circuit (8) is a rectifier circuit (
It consists of a transistor Qrs, which is a switching element that chops the output of 2), and a control circuit (6), for example, an astable multi-pipe circuit, which controls on/off the transistor Q1. Vcc is the control circuit (6
) is a low voltage power supply for driving. The diode DA absorbs the electromagnetic energy f- of the choke L0 when the transistor Q1 is turned off.
This is to bypass the release of In the circuit shown in Figure 2, by controlling the transistor Q+ on and off at a frequency higher than the same wave number of the commercial power supply +1),
The power factor is improved by utilizing the energy storage effect of the current intermittent operation of the 7-channel transistor Q1 and the 7-tactasis of the choke Lo, and the pulse-shaped input current X as shown in Figure 1 (b) is
This is to prevent S. However, since the transistor Q1 intermittents the current flowing to the smoothing capacitor co via the choke Lo, the cutoff current of the transistor Q1 increases and switching loss increases. Also, commercial power supply f
A filter circuit (7
) has the disadvantage of becoming large.

Figure 8 shows yet another conventional example, in which the commercial power supply (
1), a filter circuit (7), a rectifier circuit (2), a smoothing coefficient via a choke Lo and a diode
jco is connected. Switching circuit (8)
is constructed in the same manner as in FIG. 2, and the transistor Q1 is connected between one end of the choke L0 and the negative output end of the rectifier circuit (2). As in the previous conventional example shown in FIG. This is to improve the power factor by utilizing the energy accumulation effect due to the Lo interface, and to prevent pulsed currents as shown in FIG. 1(b). However, transistor Q + choke L
If the current flowing to the transistor Q1 through the transistor Q1 is interrupted, the cutoff current of the transistor Q+ becomes large, and the switching loss becomes large as in the case of FIG. Also,
There is a problem in that the filter circuit (7) for blocking high frequency current in the commercial power supply (1) becomes large.

The present invention has been provided in view of the above-mentioned points, and an object of the present invention is to provide a rectifying power supply circuit that improves the power factor of the power supply and reduces the input current to the circuit.

An embodiment of the present invention will be described in detail below with reference to the drawings.

A filter circuit (7) and a rectifier circuit (2) are connected to the commercial power supply f1+.
) and the smoothing capacitor C via the diode D.
8 are connected. (3) is a load circuit. A series circuit of the primary winding of the trasys T1 and a transistor Q1, which is a switching element of a switching circuit (8) configured similarly to the conventional example, is connected to the output end of the rectifier circuit (2). The trassis T, 0 secondary winding is connected to the positive side of the transducer CO via the diode D2. FIG. 5 shows an operating waveform diagram. FIG. 5(a) shows the power supply voltage waveform of the ld commercial power supply (1) and the diode D.

Current flowing in 10. is shown in Fig. 5(b) in the same way as Fig. 1(b).
) flows as shown. Figure 5(f) shows the transistor Q
The current flowing through the transistor Q1 is chopped by the chopper operation of the transistor Q1 and flows as a current IQ as shown in FIG. 5(c). This current IQ+ flows as a charging current to the capacitor co via the secondary winding of the transformer T1. In this way, since the current IQ flows through the transformer T as a charging current for the capacitor C8, the current To flowing through the diode D can be reduced, and the peak current of the current IDl can be suppressed. In other words, the current ID and the current I
This is because the combined current with the current flowing to the secondary winding of Q1 via the transformer T is the charging current of the smoothing capacitor C8, and the charging current required for smoothing is approximately constant. Current ID is diode D.

The current ID flowing through the transistor Q and the current IQ+ flowing through the transistor Q are combined to form a waveform as shown in FIG. 5(d). Therefore, the input current I8 becomes a current as shown in FIG. 5(e), with high eye waves removed by the filter circuit (7). Since the input current Is is no longer a pulsed current as described above, the input power factor becomes high, and moreover,
As shown in FIG. 4, the charging current to the battery becomes a composite current of the non-chopped current ID and the chopper current IQ. Therefore, the chopper current IQ is different from the conventional example shown in FIGS. Since it can be set smaller, the switching loss of the transistor Q1 can be reduced, and since the chopper current IQI is small, the filter circuit (7) can be made smaller. Furthermore, when diode D1 and transistor Q1 turn on and off, rush current to transistor Q1 is prevented by the charging voltage of capacitor co,
When transistor Q1 turns off, transformer T1's i? ,
, is connected to the capacitor C8 so that the electromagnetic energy A is released in one direction due to the tactance.

FIG. 6 shows another example of the operation shown in FIG. 4. In FIG. 5, the on/off operation of the transistor Q1 is
During the period when the power supply voltage is low, the power supply voltage VB t! The transistor Q+ is turned on and off only near the zero point. Therefore, the current ID+ flowing through the diode D1 is
), the flow is similar to that shown in FIG. 5(b). As shown in FIG. 6(f), the transistor QI turns on and off during the period when the power supply voltage Vs is low, and accordingly the transistor Q
The current IQ1 flowing through the current IQ1 is chopped by the chopper operation only during the period when the power supply voltage Vs is low, and the current IQ1 flows as shown in FIG. 6(c). This current IQ is passed through the smoothing capacitor C by the transformer T through the secondary winding.
8 as a charging current. Current ID, ID, and IQ,
The combined current is υ as shown in Figure 6(d), and the input current is has a waveform as shown in Figure 6(e) with high wave components removed by the filter circuit (7). . still,
In Fig. 6, the diode D through which the current In does not flow is
, is turned off, the transistor Q1 is operated at high speed. Current IQ flowing through transistor Q,
flows through the transformer T as a charging current for the capacitor JCo, so the non-chopped current In can be made small, and the smoothed charging current remains almost constant, so the peak current of the current IoH can be suppressed. I can do it. Similar to the operation shown in FIG. 5, the input current Is is no longer a pulsed current, so the input power factor becomes high, and the chopper current IQ+ can be set smaller than in the conventional examples shown in FIGS. 2 and 8. Therefore, the switching loss of the transistor Q1 can be reduced, and since the chopper current IQ is small, the filter circuit (7) can be made smaller. Furthermore, compared to the case where the transistor Q1 is turned on and off over the entire cycle of the commercial power supply (1) as shown in FIG.
In the case of the figure, the current IQ flowing through the transistor Q1 becomes smaller, so the switch of the transistor Q1: /
Therefore, the loss can be further reduced, and the filter circuit (7) can also be made smaller.

Figures 7 and 8 show the transformer T in the operation of Figure 6.
The operating waveforms are shown when the turns ratio of I is changed. transformer T
, the number of turns of the primary winding is nl, the number of turns of the secondary winding is n2
In this case, Fig. 7 shows the case of the seal 1, and Fig. 8 shows the case of 5〉■. Figures 71 and 8 (a) to (e) are similar to Figure 6 (a) ” (
e) respectively. As shown in FIG. 8, during a period when the power supply voltage Vs is low, the peak value of the current ID1 flowing through the diode D1 is lowered to increase the voltage in the trasis T1 and charge the capacitor C8, and the input current Is from the commercial power supply fl is still lowered. It is possible to shorten the downtime of the power supply, resulting in a higher power factor. In other words, the conduction period of current IQ1 can be increased by boosting the voltage with the transformer 1'1 of the pre-load circuit during the period when the power supply voltage V8 is low, so that the current D
It is possible to reduce l and lower the peak value.

FIG. 9 shows another embodiment in which a choke L1 serving as an intertasis is used in place of the transformer T, and a series circuit of the choke L and a transistor Ql is connected to the output terminal of the rectifier circuit (2). are connected in parallel. Connection between choke L1 and transistor Q, and diode D2
is connected to the positive electrode side of the smoothing capacitor Co. By performing the same operation as in FIGS. 5 and 6 in this circuit, similar effects can be obtained.

FIG. 10 shows a specific embodiment of the present invention, and the load circuit (3) shown in FIG. It is composed of a connected stabilizing element ZC and a discharge lamp (10) such as a fluorescent lamp.

A completely smoothed DC voltage of 1 decisa Co is converted into a high frequency voltage VHF containing no low frequency ripple by a transistor isciverter circuit (9) using two transistors 'rr I 'rr2, and this high frequency Voltage V
A discharge lamp (10) is lit using HF. The discharge lamp (10) is lit with a high eye wave voltage VHF that does not include low in-wave ripples, improving efficiency and increasing the efficiency of the discharge lamp (10).
) stable lighting can be obtained, and moreover, a high input power factor can be obtained by the present invention. Note that the low frequency power supply VCC of the control circuit (6) is obtained from the winding of the oscillation transformer OT of the inverter circuit (9).

By the way, in the circuit shown in FIG. 1, the voltage of the capacitor Co becomes a DC voltage approximately at the peak value of the power supply voltage Vs, but in the circuit shown in FIG. Since the diode DA and the diode DA constitute a pressure reducing chopper, the voltage of the capacitor C6 is smaller than that in the case of FIG. In the circuit shown in Figure 3, the choke L
. , transistor Q1, and diode D1 constitute a boosting type chopper, so the voltage across capacitor Co becomes larger than in the case of FIG. Therefore, FIGS. 2 and 8 have the same power supply voltage Vs and load circuit (3
), the load will be too small in the circuit shown in FIG. 2, and too large in the circuit shown in FIG.

Therefore, in order to set the load power to be the same as that shown in FIG. 1, it is necessary to adjust the power supply voltage Vs or the load circuit (3). In the circuit shown in Fig. 4, especially when the operation shown in Fig. 6 is performed, the voltage of the capacitor Co is almost the same as that in Fig. 1 (the DC voltage is almost the peak value of the power supply voltage VS).
Therefore, the power supply voltage v8 and the load circuit (
3) can be applied as is, and the power supply voltage Vs and load circuit (3) can be applied as is.
) does not need to be adjusted.

Figure 11 shows another embodiment, in which the rectifier circuit +2) +2γ
Two sets are provided. One rectifier circuit (2)' is directly connected to the smoothing capacitor 'JSCo', and the other rectifier circuit (2)'
2) is provided through a shift filter circuit (7) from the commercial power supply +1), and is connected from the output end of the rectifier circuit (2) to a capacitor C0 through a transformer T1 and a diode D.

The primary winding of the transformer T is connected in series with the transistor Q1 of the switching circuit (8). In this circuit, a combined current of the low frequency current from the rectifier circuit (2)' and the chopped high frequency current passed through the other rectifier circuit (2) and the transformer T1 is supplied to the capacitor C8. Therefore, since the low frequency current and the chopped current (high frequency current) can be separated, the filter circuit (7) can be made smaller than the case shown in FIG. 4. In other words, since high frequency current no longer flows in the rectifier circuit (2γ),
The loss of the rectifier circuit (2Y can be reduced, and the other rectifier circuit (2) includes the primary winding of the transformer T1 and the transformer Q.
This is because the loss is originally small since only the current flows through the circuit 1. Furthermore, as shown in FIG. 12, a transformer T may be used instead of the filter circuit (7).

As described above, the present invention connects a smoothing capacitor to the output end of a rectifier circuit that rectifies commercial power into direct current, connects a load circuit to both ends of the capacitor, and performs on/off operation at the same wave number higher than that of the commercial power. A series circuit consisting of a switching element that performs switching and an inductance that stores and releases electromagnetic energy by the oscillation of the switching element is connected in parallel to the output terminal of the rectifying circuit, and when the switching element is turned on, a series circuit is connected in parallel to the output terminal of the rectifying circuit. Since the accumulated electromagnetic energy is released to the capacitor when the switching element is turned off and a charging current is supplied to the capacitor, the charging current to the capacitor from the rectifier circuit and the switching element are When the switching element is turned off by the choppered current, the smoothing capacitor is charged with a composite current of the charging current generated by the release of the electromagnetic energy f- of the inductance, so the input current is a pulsed current as in the conventional case. In addition, the current flowing through the switch element is different from the total current charging the capacitor, and the electromagnetic energy stored in the tactasis connected in parallel to the rectifier circuit is Since the current is small because it is only 100%, it has the effect of reducing the switching loss of the switching element.

[Brief explanation of drawings]

Figures 1(a) and 1(b) show the basic circuit diagram and waveform diagram of the conventional example.
FIG. 2 is a circuit diagram of another conventional example, FIG. 8 is a circuit diagram of still another conventional example, FIG. 4 is a specific circuit diagram of an embodiment of the present invention, and FIG. 5 is a circuit diagram of another conventional example.
Figures (a) to (f) are operation waveform diagrams of the same as above, and Figures 6 (a) to
(f) is an operational waveform diagram of the same as above, and Figures 7(a) to (e) are waveform diagrams of operation 1 when the turns ratio of the transformer shown above is set to 3=1. e) is an operating waveform diagram when the turns ratio of the transformer is Ll1〉■, FIG. 9 is a specific circuit diagram of another embodiment same as above, FIG. 10 is a specific circuit diagram showing a specific embodiment same as above, FIG. 11 and FIG. 12 are specific circuit diagrams when two sets of rectifier circuits are used. (1) is commercial power supply, (2) is rectifier circuit, (3) is load circuit, (7) is filter circuit, VS supply voltage, co is smoothing capacitor, T is transformer, D is diode, Ll indicates chalk. Agent Patent Attorney Ishi 1) Long Figure 71 (0) ('Q') Procedural Amendment (Method) November 1, 1980 Patent Application No. 128201 2, Name of Invention Rectifier Power Supply Circuit 3 , Relationship with the case of the person making the amendment Patent applicant Location 1048 Oaza Kadoma, Kadoma City, Osaka Name (583) Matsushita Electric Works Co., Ltd. Representative Iku Kobayashi 4 Agent postal code 530 ・-1! 7 5. Correction as shown in the date attached to the amendment order Application number: Japanese Patent Application No. 1982-128201 1, “Figures 5 (a) to (f)” in line 3 of page 17 of the specification of the present application Figure 5” is corrected. 2. Delete the entire text of page 17, line 4, and insert the following sentence. "Is the same as above operation waveform diagram, Figure 7 is same as above" 3, same as above No. 17
Page 6th line [Figure 8 (al~(e)j) is all corrected to ``Figure 8.'' Agent Patent Attorney Ishi 1) Cho 7 (1)

Claims (1)

[Claims] (1) A smoothing capacitor is connected to the output end of a rectifier circuit that rectifies commercial power into direct current, and a load circuit is connected to both ends of the capacitor, and the on/off operation is performed at the same wave number higher than that of the commercial power. A series circuit consisting of a switching element that performs the above-mentioned switching and an interface that accumulates and releases electromagnetic energy by the on/off operation of this switching element is connected in parallel to the output terminal of the rectifier circuit, and when the switching element is turned on, the interface A rectifying power supply circuit comprising a rectifying power supply circuit configured to discharge electromagnetic energy accumulated in the capacitor to the capacitor when the switch element is turned off, thereby supplying a charging current to the capacitor. (2) The rectifying power supply circuit according to claim 1, wherein the switching element is operated on and off only during a period when the power supply voltage of the commercial power supply is low. (8) Connect a series circuit of the switch element and the primary winding of the transformer in parallel to the output end of the rectifier circuit, and connect the secondary winding of the transformer to the positive terminal side of the smoothing condenser through the diode. Connect, the number of turns of the primary winding of the transformer is 01
and the number of turns n2 of the secondary winding is −”>1. The rectifying power supply circuit according to claim 1 or 2 of the present invention. (4) Output of the rectifying circuit A diode is connected between the end and the smoothing capacitor, and a switch element and a tactance are connected between the connection between the rectifier circuit and the diode and the other end of the output end of the rectifier circuit. The rectifier power supply circuit according to claim 1 or 2, characterized in that the switching element is turned on and off during an off period. (5) A rectifier circuit and a smoothing capacitor 7 are provided in the power supply for the section. connect a load circuit through the commercial power supply, connect another rectifier circuit in parallel to the commercial power supply through a filter circuit, connect a series circuit of a switch element and an interface to the output end of the other rectifier circuit, One end of the inductance is connected to the positive electrode side of the smoothing capacitor, and the switching element is turned on and off at the same wave number higher than that of the commercial power supply.
2. The rectifying power supply circuit according to claim 1, wherein the rectifying power supply circuit is configured to discharge the energy to the smoothing capacitor when the switching element is turned off.