JP3275215B2 - Inverter device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter for lighting a discharge lamp, for example, and more particularly to an inverter capable of outputting a high-frequency voltage having a high input power factor and low power supply harmonics.

[0002]

2. Description of the Related Art FIG. 24 is a circuit diagram of a conventional inverter device, and FIG. 25 is a waveform diagram of an input voltage and an input current of the inverter device. In the figure, 1 is an AC power supply, 2 is a rectifier circuit composed of a diode bridge or the like for rectifying the AC power supply 1, and 3 is a smoothing capacitor connected between output terminals of the rectifier circuit 2. The switching elements 4 and 5 connected in series to each other are connected in parallel to the smoothing capacitor 3. Diodes 6 and 7 are equivalently connected in antiparallel to these switching elements 4 and 5 for the purpose of flowing a regenerative current. A switch control circuit 8 drives the switching elements 4 and 5 alternately at a high frequency. A coupling capacitor 9, a current limiting inductance element 10, and a discharge lamp 12 are connected in series between a connection point of the switching elements 4 and 5 and a ground portion of the rectifier circuit 2.
The condenser 11 is connected to the discharge lamp 12 in parallel.

The conventional inverter device is configured as described above. For example, the switching elements 4 and 5 are alternately turned on and off at a certain switching frequency by a switch control circuit 8.
The high-frequency power is turned off from the connection point of the switching elements 4 and 5 via the coupling capacitor 9 and the current-limiting inductance element 10 to the discharge lamp 12 as a load element.
To supply. Then, a series resonance circuit is formed by the capacitor 11, the inductance element 10, and the capacitor 9 connected in parallel to the discharge lamp 12, and a high voltage necessary for discharging is generated from both ends of the capacitor 11, and the discharge lamp 12 is turned on. Let me. Japanese Patent Application Laid-Open No. 58-209896 discloses a technique substantially the same as the above-mentioned conventional example, and Japanese Patent Application Laid-Open No. 3-283297 discloses a circuit using the conventional example as a basic circuit.

[0004]

The conventional inverter device is of the capacitor input type as described above, and the power supply input current has a pulsed sharp current as shown in FIG. And there is a problem that power supply harmonics increase. By the way, there is a method of using a choke input type smoothing circuit to increase the input in the rectifying and smoothing circuit. However, the choke input type requires a large and heavy choke. In addition, there is a new problem that the loss due to the choke is large and is not suitable for increasing the efficiency and reducing the size of the device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is possible to increase the input power factor, reduce power supply harmonics, and reduce the size, efficiency and cost. It is intended to obtain an inverter device.

[0006]

According to a first aspect of the present invention, there is provided a rectifier circuit for full-wave rectification of an alternating current of an alternating current power supply, a charging capacitor connected to positive and negative output terminals of the rectifier circuit via a coil and a separation diode, and One end is connected to both ends of the separation diode, and the other end is connected to the negative output terminal of the rectifier circuit.The two sets of switching elements are connected in series to form a bridge. And a switch drive control circuit for outputting a high-frequency drive signal to the discharge lamp, and a discharge lamp load circuit connected via a capacitor between the connection points of the pair of switching elements.

According to a second aspect of the present invention, a pair of series-connected voltage-dividing resistors are connected in parallel to the charging capacitor, and a high-potential side of a pair of switching elements connected to the cathode of the separation diode and the pair of voltage-dividing resistors are connected. A connection point between the piezoresistor and a connection point is connected by a coupling diode.

According to a third aspect of the present invention, there is provided a rectifier circuit for full-wave rectifying an alternating current of an AC power supply, a separation diode connected to a positive output terminal of the rectifier circuit, and one end connected to both ends of the separation diode. The other end of each circuit is connected to the negative output terminal of the circuit, and two pairs of each pair constituting a bridge are connected in series.The switching element is connected in parallel to one set of switching elements connected to the cathode of the separation diode. A series-connected diode and a charging capacitor having a cathode located on the high potential side of the switching element, a switch drive control circuit for outputting a high-frequency drive signal to the two sets of switching elements, and the pair of switching elements And a discharge lamp load circuit connected via a capacitor between the connection points of the discharge lamp and a cathode of the separation diode. It is made and a series connection of a diode and a coil provided between the connection point and the connection point between the diode and the charging capacitor of the series connection of a pair of switching elements.

According to a fourth aspect of the present invention, there is provided a rectifying circuit for full-wave rectifying an alternating current of an alternating current power supply, a separating diode connected to a positive output terminal of the rectifying circuit via a coil, and one ends of both ends of the separating diode. A pair of switching elements connected to each other and connected in series to each other to form a bridge, and a pair of switching elements connected to the cathode of the separation diode. Connected in parallel with each other, a series-connected diode and a charging capacitor whose cathode is located on the low potential side of the switching element, a switch drive control circuit that outputs a high-frequency drive signal to the two sets of switching elements, A discharge lamp load circuit connected via a capacitor between the connection points of each pair of switching elements; It is made and a diode provided between the connection point and the connection point between the diode and the charging capacitor of the series connection of a pair of switching elements connected to the over-de.

[0010]

According to a fifth aspect of the present invention, a capacitor having a capacitance set so as to resonate with the coil at a frequency higher than the circuit operating frequency is connected between the positive and negative output terminals of the rectifier circuit.

[0012]

According to a sixth aspect of the present invention, in the discharge lamp load circuit, a primary coil is connected via a capacitor between connecting points of the switching elements of the respective sets, and is connected to a transformer and a secondary coil of the transformer. , And a discharge lamp having a capacitor connected in parallel.

[0014]

According to a seventh aspect of the present invention, there is provided a drive signal in which the switch drive control circuit according to the first to sixth aspects changes a frequency in accordance with an increase or a decrease in the output voltage of the rectifier circuit within each half cycle of the AC power supply. Alternatively, the amplitude is changed so as to contradict the increase and decrease of the output voltage of the rectifier circuit within each half cycle of the AC power supply, and at least one of the drive signals is output.

[0016]

According to the first aspect of the invention, the pulsating current output from the rectifier circuit is charged to the charging capacitor via the coil and the separating diode, and each of the sets of the opposing switching elements is driven by the drive signal of the switch drive control circuit. When each is turned on, a high-frequency load current flows through the switching element, the discharge lamp load circuit, the coupling capacitor, and the switching element based on the charging voltage of the charging capacitor. When the other set of opposing switching elements is turned on, the positive side of the rectifier circuit is turned on. The switching element, the coupling capacitor, the discharge lamp load circuit, the switching element and the high-frequency load current flow based on the back electromotive voltage generated in the coil connected to the output terminal, and the charging capacitor is charged through the separation diode. Is switched by the back EMF generated in the coil. Input current flows with respect to the AC voltage of the AC power supply every time a high-frequency load current flows through the switching element, the coupling capacitor, the discharge lamp load circuit, and the switching element. Alternatively, the input current flows between the opposing switching elements of one set and the opposing switching elements of the other set according to the drive signal of the switch drive control circuit. Is the same as the power supply voltage, the input current waveform approaches the input voltage waveform, the input power factor increases, and the power supply harmonics decrease.

In the second invention, a pair of series-connected voltage-dividing resistors are connected in parallel to the charging capacitor, and a high-potential side of a pair of switching elements connected to the cathode of the separation diode and the pair of switching elements are connected to each other. Since the connection with the connection point of the voltage dividing resistor is connected by a coupling diode, a high-frequency load is applied to the switching element, the discharge lamp load circuit, the coupling capacitor, and the switching element when the opposing switching elements of each of the above-mentioned one sets are turned on. Since the charging voltage of the charging capacitor for flowing the current is the divided voltage of the voltage dividing resistor, the withstand voltage of the switching element can be low.

According to the third aspect, when one of each set of the opposing switching elements is turned on by a drive signal of the switch drive control circuit, the switching element, the coupling capacitor, and the discharge capacitor are output based on the pulsating current output from the rectifier circuit. A high-frequency load current flows through the lamp load circuit and the switching element, and a pulsating current flows from the discharge lamp load circuit through the diode and the coil to the charging capacitor to charge the charging capacitor. When turned on, the diode, switching element, discharge lamp load circuit, coupling capacitor and switching element and high-frequency load current flow based on the charging voltage of the charging capacitor, so based on the pulsating current output from the rectifying circuit,
Switching element, coupling capacitor, discharge lamp load circuit,
Each time the switching element and the high-frequency load current flow, an input current flows with respect to the AC voltage of the AC power supply, and the input current flows when the instantaneous value of the pulsating current of the rectifier circuit is low or other than near the peak value, and The input current has the same phase as the power supply voltage because the on / off timing of the opposing switching elements of each set and the opposing switching elements of the other set are the same according to the drive signal of the switch drive control circuit. , The input current waveform approaches the input voltage waveform, the input power factor increases, and the power supply harmonics decrease.

When a current for charging flows through a switching element, a coupling capacitor, a discharge lamp load circuit, a diode, a coil, and a charging capacitor based on the pulsating current output from the rectifier circuit, the power supply is provided because the coil exists. A large inrush current is suppressed from flowing through the charging capacitor when being turned on.

According to a fourth aspect of the present invention, when one of each set of the opposing switching elements is turned on by a driving signal of the switch driving control circuit, the coil, the switching element, and the coupling capacitor are based on the pulsating current output from the rectifying circuit. , Discharge lamp load circuit, switching element and high frequency load current flow, and furthermore, coil, separation diode,
When the pulsating flow flows through the charging capacitor and the switching element, the charging capacitor is charged, and when the other set of opposing switching elements is turned on, the switching element, the discharge lamp load circuit, the coupling capacitor, and the switching element based on the charging voltage of the charging capacitor. Since the high-frequency load current flows through the diode and the rectifier circuit, the alternating current of the AC power supply flows every time the high-frequency load current flows through the coil, the switching element, the coupling capacitor, the discharge lamp load circuit, and the switching element. An input current flows with respect to the voltage, and the input current flows when the instantaneous value of the pulsating current of the rectifier circuit is low or other than near the peak value, and the input current flows between each pair of opposing switching elements and the other. Each pair of the opposing switching elements is driven by a drive signal of the switch drive control circuit. To flow in the same phase as the power supply voltage by the timing of the respective on-off are the same, the input current waveform approaches the input voltage waveform, the power supply harmonic is reduced with the input power factor becomes higher.

When a current for charging flows through the coil, the separating diode and the charging capacitor based on the pulsating current output from the rectifier circuit, a large rush current flows through the charging capacitor when the power is turned on because of the presence of the coil. Is suppressed.

[0022]

In the fifth invention, since a capacitor having a capacitance set so as to resonate with the coil at a frequency higher than the circuit operating frequency is connected between the positive and negative output terminals of the rectifier circuit, the rectifier circuit and the coil are connected to each other. The high voltage applied to the connection point can be reduced, and the inductance value of the coil can be reduced.

[0024]

In a sixth aspect of the present invention, the discharge lamp load circuit includes a transformer in which a primary side coil is connected between connection points of the switching elements of the respective sets via capacitors.
Since the discharge lamp is connected to the secondary coil of the transformer and has a capacitor connected in parallel, no DC flows to the discharge lamp, and the life of the discharge lamp load is prolonged.

[0026]

In a seventh aspect, the switch drive control circuit according to the first to sixth aspects has a drive signal whose frequency is changed in accordance with an increase or decrease in the output voltage of the rectifier circuit within each half cycle of the AC power supply. Alternatively, by changing the amplitude of the rectifier circuit within each half cycle of the AC power supply to output at least one of the drive signals by changing the output voltage of the rectifier circuit so as to be opposite to the increase or decrease of the output voltage of the rectifier circuit, any of the inverter devices may be provided with a rectifier circuit. When the output voltage is high, the frequency of the drive signal is high,
When the output voltage is low, the frequency of the drive signal is low, and accordingly, the drive signal is also narrow when the output voltage is high, or the amplitude of the drive signal changes according to the level of the output voltage of the rectifier circuit. As a result, the step-up ratio with respect to the charging capacitor becomes smaller as a result, and the change in the load current is also suppressed to a small value.

[0028]

【Example】

Embodiment 1 FIG. FIG. 1 is a circuit diagram of an inverter device according to a first embodiment of the present invention, and FIG. 2 is a waveform diagram of voltages and currents at respective parts of the inverter device. In the figure, 21 is a commercial AC power supply, 22 is a filter for removing high frequency components, 23 is a rectifier circuit composed of a diode bridge for full-wave rectifying the AC of the commercial AC power supply 21, and 24 is a rectifier circuit 23.
Is a step-up coil connected to the positive side output terminal. 2
5 is an isolation diode connected in series to the coil 24, 2
A charging capacitor 6 is connected to the positive and negative output terminals of the rectifier circuit 23 via the coil 24 and the separation diode 25 and charges the output of the rectifier circuit 23.

Reference numerals 27 and 28 denote a pair of serially connected switching elements having one end connected to the anode of the separation diode 25 and the other end connected to the negative output terminal of the rectifier circuit 23. One pair of switching elements connected in series, one end of which is connected to the cathode, and the other end of which is connected to the negative output terminal of the rectifier circuit 23.
The bridge is composed of 9, 30. 31 and 32 are diodes connected in parallel to a pair of switching elements 27 and 28, respectively, and 33 and 34 are a pair of switching elements 2
Diodes 9 and 30 are connected in parallel.
A switch drive control circuit 35 outputs a high-frequency drive signal to the two sets of switching elements 27 to 30. A coupling capacitor 40 is provided between the connection points of the pair of switching elements 27, 28 and 29, 30. And a discharge lamp load circuit connected through the discharge lamp. The discharge lamp load circuit 36 includes a fluorescent lamp 37 as a load element, a coil 38 connected in series to the fluorescent lamp 37, and a capacitor 3 connected in parallel to the fluorescent lamp 37.
9.

Next, the operation of the above embodiment will be described. The AC power supply voltage shown in FIG. 2A through the filter 22 of the AC power supply 21 is rectified by the rectifier circuit 23, and the rectifier circuit 23
Is output from the coil 24 and the separation diode 2
5, the charging capacitor 26 is charged. And
When one of each pair of the opposing switching elements 28 and 29 is turned on by a drive signal of the switch drive control circuit 35, the switching element 29, the discharge lamp load circuit 36, the coupling capacitor 40, and the switching element are based on the charging voltage of the charging capacitor 26. 28 and a high frequency load current. Next, when the opposing switching elements 27 and 30 of each other set are turned on, the switching element 27, the coupling capacitor 40, and the switching element 27 are activated based on the back electromotive force generated in the coil 24 connected to the positive output terminal of the rectifier circuit 23. The lamp load circuit 36, the switching element 30 and the high-frequency load current flow, and the charging capacitor 26 is charged via the separation diode 25. Such an operation is repeated alternately. At this time, the voltage at the connection point between the coil 24 and the separation diode 25 has a waveform shown in FIG. 2B, and the voltage at the connection point between the separation diode 25 and the charging capacitor 26 has a waveform shown in FIG. .

Each time a high-frequency load current flows through the switching element 27, the coupling capacitor 40, the discharge lamp load circuit 36, and the switching element 30 due to the back electromotive voltage generated in the coil 24, an input is made to the AC voltage of the AC power supply 21. A current flows, and the input current flows when the instantaneous value of the pulsating flow of the rectifier circuit 23 is low or other than near the peak value.
The input current is applied to one set of opposing switching elements 28 and 29 and the other set of opposing switching elements 2
7 and 30, since the on / off timings are the same according to the drive signal of the switch drive control circuit 35, they flow in the same phase as the power supply voltage. Therefore, as shown in FIG. As it approaches the voltage waveform, the input power factor increases and the power supply harmonics decrease. Since the filter 22 is provided between the commercial AC power supply 21 and the rectifier circuit 23, it is possible to prevent the harmonics contained in the current output from the rectifier circuit 23 from returning to the AC power supply 21.

Embodiment 2 FIG. FIG. 3 is a circuit diagram of an inverter device according to a second embodiment of the present invention, and FIG. 4 is a waveform diagram of voltages at a charging capacitor and a voltage dividing resistor of the inverter device. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description of the duplicated components will be omitted. In this embodiment, a pair of voltage dividing resistors 4 connected in series to a charging capacitor 26 is used.
1 and 42 are connected in parallel, and the high potential side of the switching element 29 of the pair of switching elements 29 and 30 connected to the cathode of the separation diode 25 and a pair of voltage dividing resistors 4
A connection diode 43 connects between the connection points 1 and 42.

Accordingly, when the opposing switching elements 28, 29 of each one set are turned on, respectively, the switching element 29, the discharge lamp load circuit 36, the coupling capacitor 40
The charging voltage E1 of the charging capacitor 26 for flowing a high-frequency load current to the switching element 28
Since the divided voltage E2 is 1,2 (see FIG. 4), the withstand voltage of the switching elements 28, 29 can be low. Accordingly, the withstand voltage of the switching elements 27 and 30 can be reduced. The operation and effect of the entire circuit of this embodiment are the first.
This is the same as the embodiment.

Embodiment 3 FIG. FIG. 5 is a circuit diagram of an inverter device according to a third embodiment of the present invention, and FIG. 4 is a waveform diagram of voltages at respective parts of the inverter device. This example is
A rectifier circuit 23 for full-wave rectification of the AC power supply voltage of the AC power supply 21 via the filter 22, a separation diode 25 connected to the positive output terminal of the rectification circuit 23, and one end connected to both ends of the separation diode 25. Rectifier circuit 2
The switching elements 27 to 30 are connected in series to each other, and two sets of pairs forming a bridge are connected to the negative output terminal of the switching element 3 and a pair of switching elements 29 connected to the cathode of the separation diode 25. , 30 connected in parallel, and a diode 47 and a charging capacitor 26 connected in series with a cathode located on the high potential side of the switching element 29, and a switch for outputting a high-frequency drive signal to the two sets of switching elements 27-30. Drive control circuit 35
And a pair of switching elements 27, 28 and 29, 3
0, a discharge lamp load circuit 36 connected via a capacitor 40 between the connection points, a diode 47 connected in series with a connection point of a pair of switching elements 29, 30 connected to the cathode of the separation diode 25, and charging. Capacitor 2
6 connected in series with the connection point
5 and a coil 46. 31-3
4 is a flywheel diode, and 48 is a bypass capacitor connected in parallel with the diode 47 and the charging capacitor 26 connected in series.

In this embodiment, the switch drive control circuit 3
5, when each of the opposing switching elements 27 and 30 of each pair is turned on by the drive signal of No. 5, the switching element 2 based on the pulsating current output from the rectifier circuit 23.
7, a high-frequency load current flows through the coupling capacitor 40, the discharge lamp load circuit 36, the switching element 30, and a pulsating current flows from the discharge lamp load circuit 36 through the diode 45 and the coil 46 to the charge capacitor 26.
6 is charged and the other set of opposing switching elements 28 and 29 is turned on, based on the charging voltage of the charging capacitor 26, the diode 47 and the switching element 2
9, high-frequency load current flows through the discharge lamp load circuit 36, the coupling capacitor 40, and the switching element 28. Such an operation is repeated alternately. AC power supply 2 at this time
6 has the waveform shown in FIG. 6A, the output voltage of the rectifier circuit 23 has the waveform shown in FIG. 6B, and the voltage of the charging capacitor 26 has the coil 46.
(C).

Based on the pulsating current output from the rectifier circuit 23, the switching element 27, the coupling capacitor 4
0, each time a high-frequency load current flows through the discharge lamp load circuit 36 and the switching element 30, an input current flows with respect to the power supply voltage of the AC power supply 21, and the input current is generated when the instantaneous value of the pulsating current of the rectifier circuit 23 is low. Alternatively, the input current flows to a portion other than the vicinity of the peak value, and the input current is supplied to the drive signal of the switch drive control circuit 35 by the opposing switching elements 27 and 30 of one set and the opposing switching elements 28 and 29 of the other set. Since the on and off timings are the same, the current flows in the same phase as the power supply voltage, so that the input current waveform approaches the input voltage waveform, the input power factor increases, and the power supply harmonics decrease.

Further, based on the pulsating current output from the rectifier circuit 23, the switching element 27, the coupling capacitor 40,
When a current for charging flows through the discharge lamp load circuit 36, the diode 45, the coil 46, and the charging capacitor 26,
The presence of the coil 46 suppresses a large inrush current from flowing through the charging capacitor when the power is turned on.

Embodiment 4 FIG. FIG. 7 is a circuit diagram of an inverter device according to a fourth embodiment of the present invention. In this embodiment, a rectifying circuit 23 for full-wave rectifying an AC power supply voltage of an AC power supply 21 through a filter 22 is used.
A separation diode 25 connected to the positive output terminal of the rectifier circuit 23 via a coil 24;
The switching element 2 is connected in series to two pairs each having one end connected to both ends of the rectifier circuit 23 and the other end connected to the negative output terminal of the rectifier circuit 23.
7 to 30 and a set of switching elements 29 and 30 connected to the cathode of the separation diode 25 in parallel,
The diode 47 and the charging capacitor 26 connected in series with the cathode located on the low potential side of the switching element 30
And a switch drive control circuit 35 that outputs a high-frequency drive signal to the two sets of switching elements 27 to 30, and a coupling capacitor 40 between the connection points of each pair of switching elements 27, 28 and 29, 30. And a charging capacitor 26 connected in series with a connection point between a pair of switching elements 29 and 30 connected to the cathode of the separation diode 25.
And a diode 45 provided between the above-mentioned connection points. Reference numeral 48 denotes a bypass capacitor connected in parallel to the diode 47 and the charging capacitor 26 connected in series.

In this embodiment, when one of each set of the opposing switching elements 27 and 30 is turned on by the drive signal 36 of the switch drive control circuit, the coil 24 and the switching element are switched based on the pulsating current output from the rectifier circuit 23. A high-frequency load current flows through the element 27, the coupling capacitor 40, the discharge lamp load circuit 36, the switching element 30, and a pulsating flow flows through the coil 24, the separation diode 25, the charging capacitor 26, the diode 46, and the switching element 30, and the charging capacitor flows. When the switching element 28 is charged and the other set of opposing switching elements 28 and 29 are turned on, the switching element 29, the discharge lamp load circuit 36, the coupling capacitor 40, and the switching element 28 Load current flows. Based on the pulsating current output from the rectifier circuit 23, the coil 24, the switching element 27, the coupling capacitor 40, the discharge lamp load circuit 36, the switching element 30
Each time a high-frequency load current flows, an input current flows with respect to the power supply voltage of the AC power supply 21.
3 flows when the instantaneous value of the pulsating flow is low or near the peak value, and the input current is applied to the opposing switching elements 27, 30 of one set and the opposing switching elements 28, 29 of the other set. Is the same phase as the power supply voltage because the on / off timings are the same according to the drive signal of the switch drive control circuit 35, so that the input current waveform approaches the input voltage waveform, the input power factor increases, and the power supply voltage increases. Harmonics are reduced. Rectifier circuit 23
When the current for charging flows through the coil 24, the separation diode 25, and the charging capacitor 26 based on the pulsating current output from the, the large inrush current flowing through the charging capacitor when the power is turned on due to the presence of the coil 24 is suppressed. Is done.

Embodiment 5 FIG. FIG. 8 is a circuit diagram of an inverter device according to a fifth embodiment of the present invention, in which a diode 50 is added to the circuit of the first embodiment. That is, a diode 50 that clips a peak voltage of a high-voltage resonance voltage generated at the output side of the rectifier circuit 23 to a voltage value applied to the charging capacitor 26 is connected in parallel to a series circuit of the coil 24 and the separation diode 25.

In this embodiment, when the diode 50 is not provided, a high frequency voltage is applied to the connection point between the coil 24 and the separation diode 25, so that the connection point between the rectifier circuit 23 and the coil 24 is When a high-frequency current flows through the coil 24, a high-voltage resonance voltage is generated by the inductance value of the coil 24 and the stray capacitance. For this reason,
The withstand voltage of the diode used for the rectifier circuit 23 is set to
It must be several times the voltage value of 1 or more. here,
By adding the diode 50, the diode 50 clips the peak voltage of the resonance voltage generated at the connection point of the coil 24 on the rectifier circuit 23 side to the applied voltage value of the charging capacitor 26, and reduces the withstand voltage of the diode of the rectifier circuit 23. In order to keep the breakdown voltage low, it is not necessary to set the withstand voltage of the diode of the rectifier circuit 23 particularly high.

Embodiment 6 FIG. FIG. 9 is a circuit diagram of an inverter device according to a sixth embodiment of the present invention, in which a capacitor 51 is added to the circuit of the first embodiment. One terminal of the capacitor 51 is connected to the rectifier circuit 22.
And the other terminal is connected to the negative output terminal of the rectifier circuit 22. That is, the coil 2 is connected between the positive and negative output terminals of the rectifier circuit 23.
4 connects a capacitor 51 whose capacity is set so as to resonate at a frequency higher than the circuit operating frequency. In this embodiment, when the capacitor 51 is not provided, a high resonance voltage is generated at the connection point between the rectifier circuit 23 and the coil 24. Here, by adding a capacitor 51 whose capacity is set so as to resonate with the coil 24 at a frequency higher than the circuit operating frequency, this high voltage is reduced, and the coil 24 is aggressively transmitted to the coil 24 via the capacitor 51. An electric current flows, and the inductance value of the coil 24 can be reduced. Therefore, by using the coil 24 having an inductance value sufficiently smaller than that of the first embodiment, it is possible to further reduce the size and cost.

Embodiment 7 FIG. FIG. 10 is a configuration diagram of an inverter device according to a seventh embodiment of the present invention. A partial smoothing circuit 53 including capacitors 54 and 55 and diodes 56, 57 and 58 is connected in place of the capacitor 26 of the circuit of the first embodiment. ing. Since the partial smoothing circuit 53 is connected in place of the capacitor 26 as in this embodiment, the voltage charged in the partial smoothing circuit 53 is の of the voltage output from the rectifier circuit 23. The withstand voltage of the elements 27 to 30 can be low.

Embodiment 8 FIG. FIG. 11 is a circuit diagram of an inverter device according to an eighth embodiment of the present invention. In FIG. 11, one of transformers 60 is used instead of the coil 38 of the discharge lamp load circuit 36 of the first embodiment.
The secondary side is connected, and a parallel circuit of the fluorescent lamp 37 and the capacitor 39 is connected to the secondary side of the transformer 60. In this embodiment, the operation is the same as that of the first embodiment, and the input power factor is increased and the power supply harmonics are reduced. Also, for example, when the switching elements 27 and 30 are turned on, a high-frequency current flows through the coil 24 to the primary side of the transformer 60, but the fluorescent lamp 30 is connected to the secondary side and is insulated. There is no danger of electric shock due to this, and safety can be improved.

Embodiment 9 FIG. FIG. 12 is a circuit diagram of an inverter device according to a ninth embodiment of the present invention, and FIGS. 13 and 14 show modifications of the ninth embodiment. In the circuits shown in FIGS. 12 to 14, the insertion point of the coil 24 of the circuit of the first embodiment is replaced with one of the power supply terminals of the rectifier circuit 23 or the negative output terminal of the rectifier circuit 23. 12, the coil 61 is inserted into one power supply terminal of the rectifier circuit 23, the coil 62 is inserted into the other power supply terminal of the rectifier circuit 23 in FIG. 13, and the negative side of the rectifier circuit 23 in FIG. The coil 63 is inserted in the output terminal. In this embodiment, the operation is the same as that of the first embodiment, and the input power factor is increased and the power supply harmonics are reduced, but the coils 61, 62, 63
Is connected to one of the power supply terminals of the rectifier circuit 23 or the negative output terminal, the influence of the stray capacitance of these coils can be eliminated.
The peak value of the high frequency voltage may be sufficient for the rectifier diode, and a rectifier diode having a low withstand voltage can be used.

Embodiment 10 FIG. 15 is a circuit diagram of an inverter device according to a tenth embodiment of the present invention, FIG. 16 is a circuit diagram showing a configuration of a switch drive control circuit of the device, and FIG. 17 is a graph for explaining the operation of the switch drive control circuit. FIG. 18 is a waveform diagram of voltages, currents, and inverter drive signals in respective parts of the inverter device having the switch drive control circuit. In the circuit of this embodiment, the voltage dividing resistors 71 and 72 connected in series are connected in parallel to the positive and negative output terminals of the rectifier circuit 23 in the circuit of the first embodiment, and these connection points are connected via a connection line 73 to the switch drive control circuit. 135. Further, the switch drive control circuit 135 of this embodiment modulates the frequency according to the output voltage of the oscillating circuit 135a that oscillates a drive signal of a predetermined frequency and the rectifier circuit 13, and outputs a drive signal having an amplitude corresponding to the frequency. And a frequency modulation circuit 135b. Other configurations are the same as in the first embodiment.

In the first embodiment, the frequency of the drive signal for driving the switching elements 27 to 30 of the switch drive control circuit 35 is constant, that is, fixed. Is connected to the switch drive control circuit 135 via the connection line 73, the pulsating current output from the rectifier circuit 23 to the switch drive control circuit 135 is provided. Of the output voltage shown in FIG.
Is input. Then, the frequency of the drive signal output from the switch drive control circuit 135 is changed with respect to the predetermined frequency of the oscillation circuit 135a.
35b varies according to the level of the divided voltage as shown in FIG. 18 (b), and accordingly, FIG.
As shown in (e), the amplitude of the drive signal is narrow when the divided voltage is high and widened when the divided voltage is low, as opposed to the level of the divided voltage. Therefore, the step-up ratio with respect to the charging capacitor 26 is reduced, and the load current is also reduced.
Have a low withstand voltage, and the load current ripple is reduced. FIG. 18F shows the waveform of the input current output from the rectifier circuit 23.

In this embodiment, the switch drive control circuit 1
Although a divided voltage of the output voltage of the pulsating current output from the rectifier circuit 23 is input to 35, the frequency of the drive signal of the switch drive control circuit 135 is changed according to the level of the divided voltage. Even when the input current output from the rectifier circuit 23 is input to the switch drive control circuit 135, the same effect is obtained.

FIG. 19 is a circuit diagram showing the configuration of another switch drive control circuit, FIG. 20 is a graph for explaining the operation of the switch drive control circuit, and FIG. 21 is an inverter device having the switch drive control circuit. FIG. 3 is a waveform diagram of a voltage and a drive signal at each part. If the switch drive control circuit 235 of this embodiment is used in the first embodiment, the pulse width modulation circuit 235b responds to the drive signal of a predetermined frequency of the oscillation circuit 235a of the switch drive control circuit 235 by the rectifier circuit 2
The pulse width of the drive signal is narrow when the divided voltage is high and widened when the divided voltage is low so as to be contrary to the level of the divided voltage of the output voltage. Therefore, the step-up ratio with respect to the capacitor 26 is reduced and the load current is also reduced, so that the charging capacitor 26 and the switching elements 31 and 3
2 has a low withstand voltage, and the load current ripple is reduced.

FIG. 22 is a circuit diagram showing the configuration of another switch drive control circuit, and FIG. 23 is a waveform diagram of drive signals of the switch drive control circuit. If the switch drive control circuit 335 of this embodiment is used in the first embodiment, the frequency of the drive signal output from the switch drive control circuit 335 is set to a predetermined frequency of the oscillation circuit 335a.
35b fluctuates according to the level of the divided voltage of the output voltage of the rectification circuit 23, and the pulse width modulation circuit 335c responds to the drive signal from the frequency modulation circuit 335b by the level of the divided voltage of the output voltage of the rectification circuit 23. The pulse width of the drive signal is narrow when the divided voltage is high, and widened when the divided voltage is low. Therefore, the frequency and the pulse width are simultaneously varied in accordance with the level of the divided voltage of the output voltage of the rectifier circuit 23. Therefore, the step-up ratio with respect to the charging capacitor 26 is further reduced, and the load current is further reduced. And switching elements 31 and 3
2 has a low withstand voltage, and the load current ripple is reduced.

In the above description, the first embodiment shown in FIG.
The switch drive control circuits 135 and 2 shown in FIGS.
35 and 335, the second to ninth embodiments are used.
In the tenth embodiment, by using the switch drive control circuits 135, 235, and 335 shown in FIGS. 16, 19, and 23 instead of the switch drive control circuit 35, the step-up ratio with respect to the charging capacitor is reduced as a result, and the load is reduced. Needless to say, the current can be suppressed to a small value, the charging capacitor and the switching element have low withstand voltages, and the ripple of the load current is reduced.

[0052]

According to the first aspect of the present invention, the pulsating current output from the rectifier circuit is charged in the charging capacitor via the coil and the separating diode, and one of the sets of the opposite switching is driven by the driving signal of the switch driving control circuit. When each element is turned on, a high-frequency load current flows through the switching element, the discharge lamp load circuit, the coupling capacitor, and the switching element based on the charging voltage of the charging capacitor, and the rectifying circuit is turned on when the other set of opposing switching elements is turned on. Based on the back electromotive voltage generated in the coil connected to the positive output terminal, the switching element, the coupling capacitor, the discharge lamp load circuit, the switching element and the high-frequency load current flow, and the charging capacitor is charged via the separation diode. The back electromotive force generated in the coil Whenever a high-frequency load current flows through the switching element, the coupling capacitor, the discharge lamp load circuit, and the switching element, an input current flows with respect to the AC voltage of the AC power supply. Alternatively, the input current flows between the opposing switching elements of one set and the opposing switching elements of the other set according to the drive signal of the switch drive control circuit. Are the same, they flow in the same phase as the power supply voltage, so that the input current waveform approaches the input voltage waveform, which has the effect of increasing the input power factor and reducing power supply harmonics.

In the second invention, a pair of series-connected voltage-dividing resistors are connected in parallel to the charging capacitor, and the high potential side of a pair of switching elements connected to the cathode of the separating diode is connected to the pair of switching elements. Since the connection with the connection point of the voltage dividing resistor is connected by a coupling diode, a high-frequency load is applied to the switching element, the discharge lamp load circuit, the coupling capacitor, and the switching element when the opposing switching elements of each of the above-mentioned one sets are turned on. Since the charging voltage of the charging capacitor for flowing the current is the divided voltage of the voltage dividing resistor, there is an effect that the withstand voltage of the switching element can be reduced.

According to the third aspect, when one of each set of the opposing switching elements is turned on by a drive signal of the switch drive control circuit, the switching element, the coupling capacitor, and the discharge capacitor are output based on the pulsating current output from the rectifier circuit. A high-frequency load current flows through the lamp load circuit, the switching element, and further, a pulsating flow flows through the diode, the switching element, the diode, the coil, and the charging capacitor to charge the charging capacitor, and the other set of opposing switching elements is turned on. Sometimes a high-frequency load current flows through the diode, the switching element, the discharge lamp load circuit, the coupling capacitor, and the switching element based on the charging voltage of the charging capacitor. Light load circuit, switch Each time the element and the high-frequency load current flow, an input current flows with respect to the AC voltage of the AC power supply, and the input current flows when the instantaneous value of the pulsating current of the rectifier circuit is low or near the peak value. The input current has the same phase as the power supply voltage because the on / off timings of the opposing switching elements in each set and the opposing switching elements in the other set are the same according to the drive signal of the switch drive control circuit. Since the current flows, the input current waveform approaches the input voltage waveform, which has the effect of increasing the input power factor and reducing power supply harmonics.

When a current for charging flows through the switching element, the coupling capacitor, the discharge lamp load circuit, the diode, the coil, and the charging capacitor based on the pulsating current output from the rectifier circuit, the power is supplied because the coil exists. There is also an effect that a large rush current is prevented from flowing through the charging capacitor when being turned on.

According to the fourth aspect of the present invention, when one of each pair of opposing switching elements is turned on by a drive signal of the switch drive control circuit, the coil, the switching element, and the coupling capacitor are based on the pulsating current output from the rectifier circuit. , Discharge lamp load circuit, switching element and high frequency load current flow, and furthermore, coil, separation diode,
A pulsating current flows through the charging capacitor, the diode, and the switching element, and the charging capacitor is charged.When the other set of opposing switching elements is turned on, the switching element, the discharge lamp load circuit, and the coupling capacitor are based on the charging voltage of the charging capacitor. Since the switching element and the high-frequency load current flow, the coil, the switching element, the coupling capacitor,
Each time a high-frequency load current flows through the discharge lamp load circuit and the switching element, an input current flows with respect to the AC voltage of the AC power supply, and the input current is generated when the instantaneous value of the pulsating flow of the rectifier circuit is low or near the peak value. In addition, the input currents of the opposing switching elements of each set and the opposing switching elements of the other set are the same due to the same on / off timing by the drive signal of the switch drive control circuit. Since the current flows in the same phase as the power supply voltage, the input current waveform approaches the input voltage waveform, which has the effect of increasing the input power factor and reducing power supply harmonics.

Further, when a current for charging flows through the coil, the separation diode and the charging capacitor based on the pulsating current output from the rectifier circuit, a large rush current flows through the charging capacitor when the power is turned on because of the presence of the coil. Is also suppressed.

[0058]

In the fifth invention, since a capacitor having a capacitance set so as to resonate with the coil at a frequency higher than the circuit operating frequency is connected between the positive and negative output terminals of the rectifier circuit, the rectifier circuit and the coil are connected. This has the effects of reducing the high voltage applied to the connection point and reducing the inductance value of the coil.

[0060]

According to a sixth aspect of the present invention, a primary coil of the discharge lamp load circuit is connected via a capacitor between connection points of the switching elements of each set, and a transformer is provided.
Since a discharge lamp is connected to the secondary coil of the transformer and a capacitor is connected in parallel, a high-frequency current flows through the primary side of the transformer, but the discharge lamp is connected to the secondary side and is insulated. In addition, there is an effect that there is no danger of electric shock due to the appliance and safety can be improved.

[0062]

In a seventh aspect, the switch drive control circuit according to the first to sixth aspects has a drive signal whose frequency is changed in accordance with an increase or decrease in the output voltage of the rectifier circuit within each half cycle of the AC power supply. Alternatively, the amplitude is changed so as to contradict the increase or decrease of the output voltage of the rectifier circuit in each half cycle period of the AC power supply, and at least one of the drive signals is output. In any of the inverter devices, when the output voltage of the rectifier circuit is high, the frequency of the drive signal is high, when the output voltage is low, the frequency of the drive signal is low, and the drive signal accordingly becomes narrow when the output voltage is high, or Since the amplitude of the drive signal also changes in accordance with the level of the output voltage of the rectifier circuit, the step-up ratio with respect to the charging capacitor is reduced as a result, and the load current is reduced. Reduction is also suppressed small, the charging capacitor and the switching element requires only one breakdown voltage is low, there is an effect that the ripple of the load current is also reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an inverter device according to a first embodiment of the present invention.

FIG. 2 is a waveform diagram of a voltage, a current, and a drive signal in each part of the device.

FIG. 3 is a circuit diagram of an inverter device according to a second embodiment of the present invention.

FIG. 4 is a waveform diagram of voltages at a charging capacitor and a voltage dividing resistor of the device.

FIG. 5 is a circuit diagram of an inverter device according to a third embodiment of the present invention.

FIG. 6 is a waveform diagram of a voltage at each part of the device.

FIG. 7 is a circuit diagram of an inverter device according to a fourth embodiment of the present invention.

FIG. 8 is a circuit diagram of an inverter device according to a fifth embodiment of the present invention.

FIG. 9 is a circuit diagram of an inverter device according to a sixth embodiment of the present invention.

FIG. 10 is a circuit diagram of an inverter device according to a seventh embodiment of the present invention.

FIG. 11 is a circuit diagram of an inverter device according to an eighth embodiment of the present invention.

FIG. 12 is a circuit diagram of an inverter device according to a ninth embodiment of the present invention.

FIG. 13 is a circuit diagram of a modification of the ninth embodiment.

FIG. 14 is a circuit diagram of another modified example of the ninth embodiment.

FIG. 15 is a circuit diagram of an inverter device according to a tenth embodiment of the present invention.

FIG. 16 is a circuit diagram showing a configuration of a switch drive control circuit of the device.

FIG. 17 is a graph for explaining the operation of the switch drive control circuit.

FIG. 18 is a waveform diagram of a voltage, a current, and an inverter drive signal in each part of the inverter device having the switch drive control circuit.

FIG. 19 is a circuit diagram showing a configuration of another switch drive control circuit.

FIG. 20 is a graph for explaining the operation of the switch drive control circuit.

FIG. 21 is a waveform diagram of a voltage and a drive signal in each part of the inverter device having the switch drive control circuit.

FIG. 22 is a circuit diagram showing a configuration of another switch drive control circuit.

FIG. 23 is a waveform diagram of a drive signal of the switch drive control circuit.

FIG. 24 is a circuit diagram of a conventional inverter device.

FIG. 25 is an input voltage and input current waveform diagram in a circuit of a conventional inverter device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 AC power supply 23 Rectifier circuit 24 Coil 25 Separation diode 26 Charging capacitor 27 Switching element 28 Switching element 29 Switching element 30 Switching element 35 Switch drive control circuit 36 Discharge lamp load circuit

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Kenji Kimura 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (56) References JP-A-4-163891 (JP, A) JP-A-5 -56647 (JP, A) JP-A-5-64430 (JP, A) JP-A-5-64462 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02M 7/48 H02M 7/5387 H05B 41/24

Claims (7)

(57) [Claims] 1. A rectifier circuit for full-wave rectification of an alternating current of an AC power supply, a charging capacitor connected to the positive and negative output terminals of the rectifier circuit via a coil and a separating diode, and one ends connected to both ends of the separating diode, respectively. A switching element having the other end connected to the negative output terminal of the rectifier circuit, the two pairs forming a bridge connected in series, and outputting a high-frequency drive signal to the two sets of switching elements. An inverter device comprising: a switch drive control circuit; and a discharge lamp load circuit connected via a capacitor between connection points of the pair of switching elements. 2. A pair of series-connected voltage-dividing resistors are connected in parallel to the charging capacitor, and a high-potential side of a pair of switching elements connected to a cathode of the separation diode is connected to the pair of voltage-dividing resistors. 2. The inverter device according to claim 1, wherein the point and the point are connected by a coupling diode. 3. A rectifying circuit for full-wave rectifying the alternating current of the AC power supply, a separating diode connected to a positive output terminal of the rectifying circuit, one end of each of the separating diodes is connected to both ends of the separating diode, and a negative side of the rectifying circuit. The other end of each of the output terminals is connected to a switching element connected in series with each of the two pairs forming a bridge, and a pair of switching elements connected in parallel to a cathode of the separation diode,
A series-connected diode and a charging capacitor having a cathode located on the high potential side of the switching element, a switch drive control circuit that outputs a high-frequency drive signal to the two sets of switching elements, and A discharge lamp load circuit connected via a capacitor between the connection points, and a connection point between a pair of switching elements connected to the cathode of the separation diode and a connection point between the series-connected diode and the charging capacitor. An inverter device comprising: a diode and a coil connected in series provided in the device. 4. A rectifier circuit for full-wave rectifying an alternating current of an AC power supply, a separation diode connected to a positive output terminal of the rectifier circuit via a coil, and one end connected to both ends of the separation diode, respectively. The other end of each circuit is connected to the negative output terminal of the circuit, and two pairs of each pair constituting a bridge are connected in series.The switching element is connected in parallel to one set of switching elements connected to the cathode of the separation diode. A series-connected diode and a charging capacitor having a cathode located on the low potential side of the switching element, a switch drive control circuit for outputting a high-frequency drive signal to the two sets of switching elements, and the pair of switching elements. A discharge lamp load circuit connected via a capacitor between the connection points of the elements, and a discharge lamp connected to the cathode of the separation diode. And a diode provided between the connection point of the pair of switching elements and the connection point of the series-connected diode and the charging capacitor. 5. The circuit according to claim 1, wherein the positive and negative output terminals of the rectifier circuit are connected to each other.
And resonate at a frequency higher than the circuit operating frequency.
It is characterized by connecting a capacitor with a set capacity to
The inverter device according to claim 1. 6. The discharge lamp load circuit according to claim 1, wherein the primary coil is an upper coil.
The capacitor between the connection points of each set of switching elements
Connected through a transformer and the secondary coil of the transformer.
Or a discharge lamp connected in parallel with a capacitor
The invar according to claim 1 or 5, wherein
Data device. 7. A switch drive control circuit controls a frequency by an AC power supply.
To increase or decrease the output voltage of the rectifier circuit within each half cycle of the
The correspondingly changed drive signal or amplitude is
Reciprocal increase and decrease of the output voltage of the rectifier circuit within each half cycle period
And at least one of the drive signals
And outputting the data.
Is an inverter device according to any of 6.