JPS59169370A - Inverter device - Google Patents

Abstract

PURPOSE:To enhance the input power factor of an inverter device and to reduce the waveform distortion by connecting the first inverter through a choke and a rectifier, and the second inverter through a capacitor and a rectifier and connecting the both outputs in series. CONSTITUTION:The first rectifier 2 is connected through a choke 6 across an AC power source 1 to connect the output to the first inverter 5a, the second rectifier 2b is connected through a capacitor 7 to connect the output to the second inverter 5b, the both inverters 5a, 5b are operated synchronously, and the secondary sides of the output insulating transformers 9a, 9b are connected in series to fire a fluorescent lamp 4. Accordingly, the high freguency output of an envelope having less low frequency ripple can be obtaind, the input current is combined in both delayed phase and advanced phase to increase the input power factor, and the waveform distortion is reduced to improve the input characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an inverter device that converts a commercial frequency power supply voltage to a high frequency voltage of several tens of KHz.

(Background technology) With the establishment of energy-saving technology, inverter lighting devices that energize and light discharge lamps, such as fluorescent lamps, with high-frequency power of several tens of kilohertz are now well-known technologies. This method is used because the luminous efficiency of the lamp is improved compared to commercial frequency.

However, simply converting the commercial input power to a high frequency and energizing the discharge lamp does not improve the lamp power factor compared to the lamp power factor when using the commercial frequency, and therefore the power loss in the inverter lighting device still remains. As shown in FIG. A method of energizing with a small amount of high frequency power has been adopted. Note that 5 in the figure is an inverter.

To smooth this input rectified voltage, smoothing using a large capacitance capacitor or smoothing using partial feedback of the inverter output is used. However, if the input rectified voltage to the inverter is completely smoothed in this way, the power factor of the lamp becomes almost 1, reducing loss in the inverter and realizing a highly efficient lighting device, but on the other hand, the input power factor decreases. A deteriorating disadvantage occurs. This means that the input commercial power is 5 Q Hz or 6 Q
While power with ripples of Hz is supplied, the input smoothing section converts it into smoothed power (voltage), which naturally results in a decrease in power factor.

In order to prevent such a decrease in the input power factor, the following methods have been considered. A concrete example of this is shown in FIG.

In FIG. 2, the delayed phase current i caused by the AC side choke 6
The input power factor is improved by combining L and the advanced phase current 1 (by the AC side capacitor 7).

However, although this method certainly improves the power factor, it has the disadvantage that there are many high-frequency components in the amount of input current. This is the voltage valve adjustment of the full wave rectifier 2 for the filter phase.
(b) This is due to 1. The state of the input current i is shown and explained in Figure 3. For ease of understanding, FIG. 3 is drawn without the smoothing circuit 2 in FIG. 2. The inverter 5 and the discharge lamp 4 can be considered to have a power factor of approximately 1,000 in the operating state, and therefore can be easily thought of as resistive loads. At this time, it is clear that the output voltage VD of the full-wave rectifier 2 has the waveform shown by the solid line in Figure 3 (at). 1 (as shown in the same figure (al), the rectified voltage ■L,
■c (including the broken line) is generated as a voltage vD shown by the solid line due to the voltage discrimination action of the rectifier 2, and the lagging current IL and leading phase current 1 at this time are shown in the same figure (cl,
In the end, the input current i will be formed as shown in +bl in the same figure, which naturally results in a high input power factor. However, as is clear from the figure (bl) It can be seen that the input current i has a rectangular waveform, and the odd harmonics including the third harmonic also increase.The waveform VB in the same figures (al and fbl) is the power supply voltage waveform.

As mentioned above, in the conventional example, if the input power factor is improved and the low frequency ripple of the high frequency voltage that energizes the discharge lamp is reduced, the harmonic component of the input current increases. . Furthermore, in order to smooth the input rectified voltage, a smoothing capacitor of considerably large capacity is also required, which also has the drawback of increasing the shape and cost of the lighting device. Furthermore,
When the load of the lighting device is high capacity, for example, when lighting multiple discharge lamps, or when the load is several hundred W discharge lamps such as HID lamps, an inverter device is required. Since there is only one in-tweeter, it is necessary to considerably increase the current and voltage withstand capacity of the elements that make up the in-tweeter, resulting in a very thick shape (and high cost), making it impractical for high-capacity loads. It also had the disadvantage of being quite difficult to convert.

(Object of the Invention) The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide an inverter device that converts a commercial frequency power supply voltage to a high frequency voltage. The purpose is to reduce ripple, improve input power factor, and further reduce harmonic components of input current to improve input characteristics.

(Disclosure of the Invention) FIG. 4 shows a circuit 1 showing an embodiment of the present invention, in which one end of the AC input side of the first upper aftereffect rectifier 2a is connected to one line of the single-phase commercial power supply 1 via a choke 6. , commercial power supply 1
The other wire is connected to the other end of the AC input side of the full-wave rectifier 2a. The anode side of the DC side output terminal of the aftereffect rectifier 2a is connected to the intermediate tap of the primary winding of the transformer 9a via the constant current choke 8a, and the
The collectors of the pair of transistors 11a and 11b are connected, and the common connection terminal of each emitter is connected to the negative side of the DC output terminal of the aftereffect rectifier 2a. A capacitor 0a is connected in parallel to both ends of the primary winding of the transformer 9a, resistors isa and 15b are connected between the base terminals of both transistors 11a and Ilb, and a DC power source 15a is connected to the common connection terminal of the resistors 13a and 13b. The anode terminal is connected, and the negative terminal is connected to the negative terminal of the full-wave rectifier 2a.

On the other hand, one end f of the AC input side of the second full-wave rectifier 2b is connected to the same line as the commercial power supply 1 to which the choke 6 is connected via the capacitor 7, and the other line of the commercial power supply 1 is connected to the AC input side of the full-wave rectifier 2b. Connect to the other end. The DC side output end of the full-wave rectifier 2b is connected to a second constant current push-pull inverter 5b having the same specifications and configuration as the constant current push-pull inverter 5a.
The output terminal of the first aftereffect rectifier 2a is connected to the first inverter 5a in the same manner as the connection to the first inverter 5a. Also, both inverters 5a
.

output windings 17a, 17b of transformers 9a, 9b of
and the discharge lamp 4 is connected between the other ends. Output windings 17a of both transformers 9a, 9b.

A capacitor 18 and a transformer 19 are connected to the non-common connection end of 17b.
are connected in series, and the two secondary windings 16a of the transformer 19,
Both terminals of transistor 16b are connected between the base terminals of transistors 11a and 12a (of both inverters 5a' and 5b) and between the base terminals of transistors 11b and 12b, respectively.

Next, the operation of the inverter device will be explained with reference to the operation waveform diagram shown in FIG. When the power supply voltage Vl is generated from the commercial AC power supply 1, the full-wave rectified voltage V of the power supply voltage VS
L, VC or 1st. It appears at the output end of the second full-wave rectifier 2a, 2b. Next, the operation of the first inverter 5a will be described. The full-wave rectified voltage vL appearing in the first aftermath rectifier 2a is the choke 8a, transformer 9a (7) i
A voltage is applied between the collectors and emitters of the transistors 11a and 12H via the next winding, but since the transistors 11a and 12a are conductive due to the DC power supply 15a, collector current flows through the transistors 11a and 12a, and the transformer One of the primary windings extending from the intermediate tap point of the primary winding 9a to both transistors 11a and 12a becomes saturated first, and from this point on, a voltage V.sub.2 is generated in the output winding 17a. Now, when voltage Vl is generated in the direction shown in FIG. 4, transistor 11a is generated due to the connection direction of secondary winding 16a of transformer 19.

A voltage 2 is generated between the base terminals of the transistor 12a in the direction shown in the figure, and operates to turn off the transistor 12a and turn on the transistor 11a. On the other hand, due to the presence of the capacitor 10a, the voltage V■ exhibits an oscillating voltage, and the voltage Vl
When the polarity of VN is reversed, the polarity of voltage VN is also reversed, transistor 11a is turned off, and transistor 1
2a is turned on. At the time of this inversion, the transistor ila through which the collector current of the transistor 11a was flowing
Trance on the side? Electromagnetic energy is stored in the primary winding of a, and when the transistor 11a is off, it is released as a charging current to the capacitor 10a, which works to maintain the oscillation of the voltage V1, and thereafter the voltage Vl has a sinusoidal shape. Oscillating voltage is generated isolated from the primary winding. Similarly, a sinusoidal oscillating voltage is generated in the secondary winding 17b of the transformer 9b of the second inverter 5b. At this time, the transistors 11a and iib and the transistors 12a and 12b are in the same state because their inverting operations are controlled by the secondary windings 16a and 16b of the transformer 19, which contain the same signal, and therefore both output windings 17a.

A synchronized oscillating voltage can be obtained from the voltage generated between each terminal of the terminal 17b.

Now, in this way, the voltage generated across the discharge lamp 4 becomes a high frequency voltage with less low frequency ripple. This is due to the following reason. In the present invention, since the output high-frequency voltage is a series combination of the outputs of the two constituent inverters, it becomes the same as adding the instantaneous values of the input DC voltages of the two inverters 5a and 5b.

On the other hand, since each inverter 5a, 5b is connected in series with an AC power source via a choke 6 and a capacitor 7,
The first aftermath rectifier 2a has a lagging current iL with respect to the power supply voltage V5, and the second full-wave rectifier 2b has a leading phase current i.
c flows. In addition, the load power factor seen from both rectifiers 2a, 2b to both inverters 5a, 5b is approximately (at low frequencies), so it is considered to be a low resistance, and both rectifiers 2a, 2b
The AC-side input terminal voltages of , respectively, generate a lagging phase voltage vL x a leading phase voltage vc with respect to the power supply voltage. This situation is shown in Figure 5 f.
It is shown at. Therefore, the input current i is the slow phase current i
Since it is a combination of L and phase advance current 1, it is clear that the power factor will be high.

Further, it is clear that the slow phase current iL and the fast phase current j (like the conventional example) have a rectangular waveform due to the voltage discrimination effect in the aftereffect rectifier.From the above, according to the present invention, the discharge lamp The input power factor of the inverter type lighting device is set to a high power factor,
Also, without smoothing the hexagonal rectified voltage to the inverter,
A highly efficient lighting device can be realized by generating a high frequency voltage with little low frequency ripple and maximizing the luminous efficiency of the discharge lamp.

In the present invention, the low frequency ripple is the slow phase current iL
It is also clear that the value determined by the phase angle θ between the leading phase current 1 (and If I sin (ut) iL=I sin (ωt-θ), then the input voltage vL s vC to both full-wave rectifiers 2a and 2b shown in FIG. 4 is expressed by the following equation.

VC=R-15in (ut) VL=R111sin (ωt-θ) where k is the equivalent impedance on the output side seen from the full-wave rectifiers 2a and 2b.

Then ζ is the output voltage V in the present invention. Since ut is determined by adding the output voltages of each inverter 5a and 5b, the output voltage V
. The low frequency envelope of ut can be found using the following equation.

Output voltage v. u, low frequency envelope = kx (1vcl+
lvt, l) = k-R-I (l sin ut l
+jsin (ω to -θ) l ) −−−−−・<
1+k here is the ratio of the maximum instantaneous value of the output high frequency voltage to the instantaneous value of the input voltage of the inverters 5a, 5b.

From the above equation (1), the phase angle θ and the low frequency ripple ratio (maximum value of the low frequency envelope of the output voltage V.ut + output voltage V.ut
When the relationship with the minimum value of the low frequency envelope of Therefore, it can be seen that at a phase angle of θ, the ripple ratio is the smallest, the maximum lighting power of the discharge lamp is not required, and the luminous efficiency is maximized. However, when adjusting the phase angle θ to 2, the type of discharge lamp, the variation within the same type,
Alternatively, in view of variations in circuit constants and variations in load capacity (variations in the number of discharge lamps), the phase angle θ actually varies from - to 'ltc.

3 It should be noted that the present invention is not limited to the above embodiments,
Of course, changes can be made within the scope of the claims.

(Effects of the Invention) As described above, the present invention provides a first
The AC input end of the aftereffect rectifier is connected, and the DC output end of the rectifier is connected to the DC input end of a first high frequency conversion circuit having an output isolation transformer. A second high-frequency conversion circuit having approximately the same specifications as the first high-frequency conversion circuit, which has an isolation transformer that connects the AC input end of a second full-wave rectifier through an element exhibiting a natural impedance and outputs the DC output end of the rectifier. It is connected to the DC input terminal of the high frequency conversion circuit, operates the first and second high frequency conversion circuits in synchronization, and combines the isolated outputs of the high frequency conversion circuit in series, and loads the combined output terminal. Because it is connected, a high-frequency output with an envelope with little low-frequency ripple can be obtained, and the input power factor can be made high, and the waveform distortion of the input current is small, and odd-order harmonic components can be obtained. We were able to provide an inverter device that can reduce the amount of electricity and increase efficiency in power transmission and distribution.

Note that if such an inverter device is used to light a discharge lamp, a highly efficient lighting device with high luminous efficiency can be provided, and it is also possible to connect a high capacity load such as a multi-lamp lighting device such as an HID lamp or a fluorescent lamp. Also, since the high frequency conversion section is divided into two parts, a sufficient function can be achieved even with the use of elements with low resistance, and both cost and size can be reduced.

[Brief explanation of drawings]

@ Figures 1 and 2 are simplified circuit diagrams of the conventional example, Figure 3 is an operation waveform diagram of the above conventional example, Figure 4 is a circuit diagram showing an embodiment of the present invention, and Figure 5 is the above embodiment. FIG. 6 is a characteristic diagram showing the ripple ratio with respect to the phase angle. Patent applicant Matsushita Electric Works Co., Ltd. Patent attorney Toshimaru Takemoto (and 2 others) Figure 1 Figure 2 Figure 3 (a) (b)

Claims (3)

[Claims] (1) The AC input end of a first full-wave rectifier is connected to both ends of an AC power supply via an element exhibiting inductive impedance with respect to the power supply frequency, and the DC output end of the rectifier is connected to a first full-wave rectifier having an output isolation transformer. is connected to the DC input end of the high frequency conversion circuit of the second full-wave rectifier, and the AC input end of the second full-wave rectifier is connected to both ends of the AC power supply via an element exhibiting capacitive impedance with respect to the power supply frequency. The DC output terminal is connected to the DC input terminal of a second high frequency conversion circuit having substantially the same specifications as the first high frequency conversion circuit and having an output isolation transformer, and the first and second high frequency conversion circuits are synchronized. An inverter device which combines insulated outputs of both high frequency conversion circuits in series while operating, and connects a load to the combined output terminal. (2) The inverter device according to claim 1, characterized in that it has the inductive impedance and the capacitive in constant. (3) The inverter device according to claim 1 or $2, wherein the first and second high frequency conversion circuits are constant current push-pull inverter circuits.