JPH05316733A - Rectifier - Google Patents

Abstract

PURPOSE:To provide a rectifier having high input power factor, small size, weight and a high efficiency. CONSTITUTION:A low frequency voltage to be supplied from an AC power source 1 is rectified by a rectifier 2, and an output voltage of the rectifier 2 is smoothed by a capacitor C2 as a smoothing circuit 3. An output voltage of the circuit 3 is supplied to an inverter 5 as a load. An inductor L1 as a high frequency cut-off filter is inserted between the power source 1 and the rectifier 2. A high frequency voltage is applied from the inverter 5 between output terminals of the rectifier 2 through a transformer T1 and the capacitor C2. A pulselike input current flows by the high frequency voltage substantially in an entire range of one period of the voltage of the power source 1, and an input power factor is improved. The improvement in the power factor is conducted in a high frequency manner, an inductance value of an inductance component for constituting the filter is reduced, the rectifier is decreased in size and weight, low frequency loss due to the inductance component is decreased, and a decrease in its efficiency is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectifying device for rectifying and smoothing a power source voltage of an AC power source to obtain a DC voltage.

[0002]

2. Description of the Related Art In a discharge lamp lighting device for lighting a lamp at a high frequency by using an inverter device, a rectifier device obtains a DC voltage from an AC power source and supplies this DC voltage as a power source to the inverter device. FIG. 3 shows an example of the rectifying device. This rectifying device is a capacitor input type rectifying device, and is composed of a rectifying circuit 2 composed of a diode bridge for rectifying the AC power supply 1 and a smoothing circuit 3 composed of a capacitor C for smoothing the rectified output of the rectifying circuit 2. There is. The output of this rectifying device is given to, for example, the inverter device 5, and the lamp 6 is turned on by the high frequency power converted by the inverter device 5.

FIG. 4A shows the waveform of the power supply voltage V _S of the AC power supply 1, which is rectified and smoothed as shown in FIG. 4B by passing through a rectifying device. Here, FIG. 4B shows the waveform of the voltage Vc across the capacitor C as the rectified and smoothed output, and FIG. 4C shows the input current is. By the way, in the case where the load of such a rectifying device is the inverter device 5 that turns on, for example, a fluorescent lamp as the lamp 6 at a high frequency, when a sufficiently smoothed DC voltage is supplied to the inverter device 5, the luminous efficiency of the lamp 6 is increased. It is known that the power consumption is increased and the loss of the circuit is reduced.

In the case of supplying the sufficiently smoothed DC voltage from the rectifying device to the inverter device 5, the capacity of the capacitor C in the rectifying device may be increased. However, when the capacitance of the capacitor C is increased in this way, the input current is becomes pulse-shaped as shown in FIG.
There is a problem in that the input power factor decreases and the input current is large, resulting in a large loss in the power supply line and the like.

Therefore, in order to solve this problem, the rectifier may be a choke input type shown in FIG. In the case of this choke input type rectifier, the choke L
If the inductance of is increased, the input current becomes fairly continuous, and the input power factor can be made high.

[0006]

However, in the case of the choke input type, since the size of the choke L is large and heavy, the rectifier is large and heavy, and the loss in the choke L is large, so that the efficiency is lowered. There is a problem of doing. The present invention has been made in view of the above points, and an object thereof is to have a high input power factor, a small size,
It is to provide a lightweight and highly efficient rectifying device.

[0007]

In order to achieve the above object, the present invention provides a low-frequency AC power supply, a rectifying circuit for rectifying a low-frequency voltage supplied from the low-frequency AC power supply, and a rectifying circuit for the rectifying circuit. In a rectifying device including a smoothing circuit that smoothes an output voltage and a load that receives the output voltage of the smoothing circuit, a high-frequency cut filter that is interposed between the low-frequency AC power supply and the rectifying circuit, and the rectifier. A transformer in which a primary winding is inserted between a circuit and a smoothing circuit, and a secondary winding of this transformer is in a state in which the output terminal voltage of the rectifier circuit is lower than the input terminal voltage of the rectifier circuit. And a high-frequency generating means for applying a high-frequency voltage generated in a pulse train over substantially the entire area of one cycle of the low-frequency voltage.

A device for converting the DC output from the smoothing circuit into a high frequency output may be used as the load, and the load may also serve as the high frequency generating means.

[0009]

The present invention has the above-mentioned configuration,
A high-frequency voltage applied between the rectifier circuit and the smoothing circuit via the transformer from the high-frequency generating means, a pulse train-shaped input current is caused to flow over substantially the entire period of one cycle of the low-frequency voltage of the low-frequency AC power supply, A high-frequency cut filter is constructed by extending the period during which the input current per cycle of the low-frequency voltage of the low-frequency AC power supply flows, improving the input power factor, and improving this input power factor at high frequencies. By reducing the inductance value of the inductance component, making the high-frequency cut filter small and lightweight, and making the rectifier small and lightweight, and reducing low-frequency loss due to the inductance component, efficiency is not reduced.

[0010]

1 and 2 show an embodiment of the present invention. Similarly to the rectifier of FIG. 3, the rectifier of this embodiment also has a rectifier circuit 2 including a diode bridge for full-wave rectifying a low frequency voltage supplied from an AC power source 1 as a low frequency AC power source. , A smoothing circuit 3 including a capacitor C ₂ for smoothing the output voltage of the rectifying circuit 2, and the output of the rectifying device is given to an inverter device 5 as a load for converting a DC voltage into a high frequency AC voltage. The inverter device 5 turns on the lamp 6 at a high frequency.

The rectifying device of this embodiment is characterized in that it has the following configuration. That is, the inductor L ₁ as the _first high frequency cutting filter and the inductor L ₂ as the second high frequency cutting filter are inserted between the AC power supply 1 and the rectifier circuit 2 and A capacitor C ₁ as a low frequency cut filter is connected to both ends via the inductor L ₁ . Then, by connecting a capacitor C ₂ for smoothing through the transformer T ₁ to the output ends of the rectifier circuit 2 is supplied to the rectifier circuit 2 to the high-frequency voltage from the inverter device 5 via the transformer T ₁ and the capacitor C ₂ There is. In addition, in the case of the present embodiment, the inverter device 5, which is the load of the rectifying device, sets the state where the output end voltage of the rectifying circuit 2 is lower than the input end voltage of the rectifying circuit 2 to one cycle of the voltage of the AC power supply 1. It also serves as a high-frequency generation means for applying a high-frequency voltage generated in a pulse train over substantially the entire area.

Here, the inductor L ₁ as the first high-frequency cut filter cuts off the high-frequency voltage supplied to the rectifier circuit 2 while passing the low-frequency voltage of the AC power supply 1, and the high-frequency voltage is the AC power supply. It is provided to prevent application to the first side. Further, the capacitor C ₁ as a low frequency cut filter prevents the high frequency voltage from being supplied to the AC power supply 1 side by bypassing the high frequency component, and the high frequency voltage superimposed from the inverter device 5 is rectified by the rectifier circuit 2. It is provided in order to effectively give to. Furthermore, the second
The inductor L ₂ as a high frequency cut filter of
It is provided in order to limit the peak value of the current ir ₁ flowing in the rectifier circuit 2 and widen the pulse width.

Capacitor C of the rectifying device₁Both ends of
Pressure Vr₁Is the power supply voltage V of the AC power supply 1 shown in FIG.
The sine wave is almost the same as s, and the voltage at the output end of the rectifier circuit 2
Vr ₂Is a DC voltage inverter as shown in Fig. 2 (c).
Device 5 to transformer T₁And capacitor C₂Through high
The frequency voltage is superposed. Output of this rectifier circuit 2
Voltage Vr at power end₂Capacitor C₂Smoothed by
An almost constant DC voltage shown in (b) is obtained.

In the rectifier circuit 2 of this embodiment, | V
Since a current flows at the moment r ₁ |> Vr ₂ , the waveform of the current ir ₁ flowing through the rectifier circuit 2 has a pulse train shape as shown in FIG. Here, the current ir ₁ flowing in the rectifier circuit 2 is limited by the inductor L ₂ as a second high-frequency cutting filter inserted into the input of the rectifier circuit 2, and the peak value of the current ir ₁ flowing in the rectifier circuit 2 is limited. By increasing the pulse width, the rectification efficiency is improved.
Further, the input current is becomes a sinusoidal current as shown in FIG. 2E due to the inductor L ₁ and the capacitor C ₁ . Therefore, the input power factor is improved. Further, by improving the input power factor at a high frequency in this way, the inductors L ₁ and L ₂ and the capacitor C ₁ can be made small, the rectifier can be made compact and lightweight, and the inductors L ₁ and L ₂ can be made smaller.
Since the inductance value of is small, low-frequency loss is reduced and efficiency is not reduced.

[0015]

As described above, the present invention provides a low-frequency AC power supply, a rectifying circuit for rectifying a low-frequency voltage supplied from the low-frequency AC power supply, and a smoothing circuit for smoothing the output voltage of the rectifying circuit. A rectifying device comprising a load receiving the output voltage of the smoothing circuit, and a high-frequency cut filter interposed between the low-frequency AC power supply and the rectifying circuit, and between the rectifying circuit and the smoothing circuit. The state in which the output terminal voltage of the rectifier circuit is lower than the input terminal voltage of the rectifier circuit in the transformer in which the primary winding is inserted and in the secondary winding of this transformer Since a high-frequency generating means for applying a high-frequency voltage generated in a pulse train is provided over substantially the entire area, a high-frequency voltage applied between the rectifying circuit and the smoothing circuit from the high-frequency generating means through a transformer is used. The input current in the form of a pulse train can be made to flow over almost the entire period of one cycle of the low-frequency voltage of the current power supply, and the period during which the input current flows per cycle of the low-frequency voltage of the low-frequency AC power supply can be extended. The input power factor is improved, and by improving the input power factor at high frequencies, the inductance value of the inductance component that constitutes the high frequency cut filter can be reduced, and the high frequency cut filter is made compact and lightweight. It is possible to reduce the size and weight, and to reduce the low-frequency loss due to the inductance component, which has the advantage of not lowering the efficiency.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the above.

FIG. 3 is a circuit diagram of a conventional example.

FIG. 4 is an explanatory diagram of an operation of the above.

FIG. 5 is a circuit diagram of another conventional example.

[Explanation of symbols]

1 AC power supply 2 Rectifier circuit 3 Smoothing circuit 5 Inverter device L ₁ inductor T ₁ transformer C ₂ capacitor

Claims (2)

[Claims] 1. A low-frequency AC power supply, a rectifying circuit for rectifying a low-frequency voltage supplied from the low-frequency AC power supply, a smoothing circuit for smoothing an output voltage of the rectifying circuit, and an output voltage of the smoothing circuit. In a rectifying device including a load to be supplied, a high-frequency cut filter inserted between the low-frequency AC power supply and a rectifier circuit, and a primary winding inserted between the rectifier circuit and a smoothing circuit. In the transformer and the secondary winding of the transformer, a state in which the output terminal voltage of the rectifier circuit is lower than the input terminal voltage of the rectifier circuit is generated in a pulse train shape over substantially the entire period of one cycle of the low frequency voltage of the low frequency AC power supply. A rectifying device, comprising: a high-frequency generator for applying a high-frequency voltage. 2. The rectifying device according to claim 1, wherein a device for converting a DC output from the smoothing circuit into a high frequency output is used as the load, and the load also serves as the high frequency generating means.