JPH0727294U - High voltage high frequency rectifier circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] A high-voltage high-frequency rectifier circuit that suppresses the influence of short-circuit current during the recovery time of the rectifier bridge diode and facilitates high-frequency operation. [Structure] A pair of high frequency transformers T for AC input voltage V _1
1, boosted by a T _2, the high-frequency transformer T _1, T ₂ pair of 4 rectifier diodes formula bridge corresponding to circuit B _1, B ₂
The high-voltage output voltage V _DC is applied to the DC load 3 from the output rectifying unit 2 in which the bridge circuits B ₁ and B ₂ are connected in series. The DC output voltage of each bridge circuit B ₁ , B ₂ is
Each bridge circuit B ₁ , corresponding to half the output voltage V _DC ,
A fast recovery diode having a low withstand voltage and a short recovery time is applied to each of the rectifier diodes D _{1 to} D ₈ of B ₂ , and the rectifier circuit can have a high frequency.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a high-voltage high-frequency rectifier circuit for a high-voltage DC load used in a DC / DC converter or a high-frequency link type DC / AC inverter.

[0002]

[Prior art]

FIG. 5 shows a general conventional example of a high-voltage high-frequency rectifier circuit that boosts a high-frequency power supply voltage and rectifies it to supply a high voltage to a DC load. A high frequency transformer T ₀ for boosting and a four-rectifying diode type bridge circuit B ₀ for full-wave rectifying the boosted AC voltage are provided. The bridge circuit B ₀ is a bridge connection of four first to fourth rectifying diodes Da to Dd, and has a middle point between the first and third rectifying diodes Da and Dc and a second and fourth rectifying diodes Da to Dd. The secondary side of the high frequency transformer T is connected to the midpoint between the rectifier diodes Db and Dd, and the midpoint between the first and second rectifier diodes Da and Db and the midpoint between the third and fourth rectifier diodes Dc and Dd. A DC load 3 is connected to via a smoothing reactor L ₁ .

FIG. 6 shows voltage waveforms and current waveforms at various points of the rectifier circuit shown in FIG. The input voltage V _{1 of the} AC waveform shown in FIG. 6A from the AC power supply 1 is boosted to a high voltage of several hundreds V or more by the high frequency transformer T ₀ , and full-wave rectified by the bridge circuit B ₀ to obtain the full-wave rectified voltage. When the output voltage V _DC having the DC waveform shown in FIG. 6 is supplied to the DC load 3, the load current I _DC having the DC waveform shown in FIG. In this case, the input current I _IN having the AC waveform shown in FIG. 6D flows through the bridge circuit B ₀ .

When the input voltage V _{1 of} FIG. 6 (a) is in the section m of zero volt, as shown in FIG. 7, the rectifying diodes Da to Dd of the bridge circuit B ₀ have forward circulation currents I _D1 and I _D2. Flow and they join to form the load current I _DC . When the input voltage V ₁ falls from the section m ₂ of zero volt to the negative side, for example, the short-circuit current I _S instantaneously flows in the bridge circuit B ₀ only for the recovery time t peculiar to the rectifying diode as shown in FIG. Even when the input voltage V ₁ rises to the positive side from the section m of zero volt, the short-circuit current I _S instantaneously flows in the bridge circuit B ₀ only during the recovery time t peculiar to the rectifier diode.

[0005]

[Problems to be solved by the device]

If the recovery time t during which the short-circuit current I _S flows through the bridge circuit B ₀ is long, the load may be short-circuited as seen from the power supply side, which may cause various malfunctions on the high-frequency power supply side. Effect on the power supply side of such short-circuit current I _S has a long recovery time t flowing short-circuit current I _S, large Kikunaru enough high frequency of the load current I _DC. The influence of such a short-circuit current I _{S on} the power supply side is suppressed by using a so-called fast recovery diode having a short recovery time t for the rectifier diodes D a to D d or by reducing the frequency of the high-voltage rectifier circuit. However, there were the following problems.

That is, in the DC load 3 that requires a high voltage of several hundreds of volts or more, the rectifier diodes Da to Dd of the bridge circuit B ₀ use high withstand voltage diodes corresponding to the high voltage of the DC load 3. Although it is necessary, the recovery time of high breakdown voltage diodes is significantly longer than that of general rectification diodes, which is a characteristic of rectification diodes. Therefore, it is impossible to apply a fast re mosquito Barry diodes each rectifier diode Da Dd of the bridge circuit B, and to no small influence as a result, the short-circuit current I _S of the high-voltage rectifier circuit is a low frequency of .

In other words, the current high-voltage rectifier circuit has a problem in that it is difficult to achieve a high frequency and its application is limited, resulting in lack of versatility. Further, since the entire rectifier circuit has a low frequency specification, it is necessary to use a large product having a large volume for the high frequency transformer T ₀ and the reactor L ₁ , and the entire rectifier circuit becomes large in size and costly. .

Therefore, it is an object of the present invention to provide a high-voltage high-frequency rectification circuit that is less affected by a short-circuit current in the recovery time of a rectification diode and that can easily achieve higher frequencies.

[0009]

[Means for Solving the Problems]

 The present invention connects a plurality of high-frequency transformers for boosting an AC input voltage and a plurality of 4-rectifier diode-type bridge circuits for full-wave rectifying the AC voltage boosted by each high-frequency transformer in series to connect an external The above object is achieved by a configuration including an output rectifying unit connected to a DC load.

In order to more reliably prevent the influence of the short-circuit current in the recovery time of the rectifying diode of the full-wave rectifying bridge circuit, the present invention provides a high breakdown voltage diode on the output side of the output rectifying unit. It is characterized in that a bypass circuit for freewheeling current consisting of a series circuit of a supersaturated reactor and a supersaturated reactor is connected in parallel.

[0011]

[Action]

 By performing full-wave rectification on each of the AC voltages boosted from the AC input voltage by multiple high-frequency transformers in the bridge circuit and supplying the DC high voltage that is the sum of the DC voltages of multiple bridge circuits to the DC load, For each rectifier diode of the bridge circuit, a low withstand voltage diode corresponding to a low voltage obtained by dividing the high voltage required for DC load by the number of AC transformers, and therefore a fast recovery diode with a short recovery time can be applied. As a result of lowering the withstand voltage of the rectifier diode, it is possible to increase the frequency of the rectifier circuit.

[0012] Further, when a circulating current bypass circuit composed of a series circuit of a high breakdown voltage diode and a supersaturation reactor is connected in parallel to an output rectification section which is a series circuit of a plurality of bridge circuits, the AC input voltage becomes zero volt in a time zone. The circulating current flows intensively in the bypass circuit, which has a smaller number of diodes than the output rectifier and a low on-voltage, and when the AC input voltage fluctuates from zero volts to the positive or negative side, the recovery time of the rectifier diode is reduced. The short-circuit current that flows instantaneously only for a short period of time also flows intensively to the bypass circuit, and this short-circuit current is blocked by the oversaturation reactor of the bypass circuit, so that the short-circuit current does not actually flow to the rectifier circuit.

[0013]

【Example】

 The first embodiment will be described below with reference to FIGS. 1 and 2, and the second embodiment will be described with reference to FIGS.

The high-voltage high-frequency rectifier circuit of the first embodiment shown in FIG. 1 corresponds to a plurality of, for example, a pair of first and second high-frequency transformers T ₁ and T ₂ and respective high-frequency transformers T ₁ and T ₂ . The output rectifying unit 2 includes a pair of four rectifying diode type first and second bridge circuits B ₁ and B ₂ connected in series. The pair of first and second high frequency transformers T ₁ and T ₂ boost the AC input voltage V ₁ and apply the boosted voltage to the corresponding first and second bridge circuits B ₁ and B ₂ .

The first bridge circuit B ₁ bridges the four rectifying diodes D _{1 to} D ₄ as in FIG. 5, and the second bridge circuit B 2 connects the four rectifying diodes D _{5 to} D ₈ to each other. The bridge connection is made in the same way as 5. The output rectifying unit 2 is configured by connecting the midpoint between the rectifying diodes D ₃ and D ₄ of the first bridge circuit B ₁ and the midpoint between the rectifying diodes D ₅ and D ₆ of the second bridge circuit B _2. To be done. An output current smoothing reactor L ₁ is provided between the midpoint between the rectifying diodes D ₁ and D ₂ of the first bridge circuit B ₁ and the midpoint between the rectifying diodes D ₇ and D ₈ of the second bridge circuit B _2. A DC load 3 is connected via the.

The AC input voltage V ₁ of the AC waveform shown in FIG. 2 (a) is boosted by the high-frequency transformer T _1, T _2, is full-wave rectified by the corresponding respective bridge circuits B _1, B _2. The DC output voltages of the bridge circuits B ₁ and B ₂ are added to form a high voltage output voltage V _DC shown in the DC waveform of FIG. 2B, which is applied from the output rectifier 2 to the DC load 3. The load current _IDC flows. At this time, the input current I _IN having the AC waveform shown in FIG. 2C flows through the bridge circuits B ₁ and B ₂ .

Now, the input voltage V of the rectifier circuit of FIG.₁ And output voltage V_DCIs the same as the rectifier circuit in FIG. 5, the first and second bridge circuits B in the rectifier circuit in FIG.₁ , B₂ DC output voltage is output voltage V_DCEquivalent to half of. Therefore, each bridge circuit B ₁ , B₂ Each rectifying diode D₁ ~ D₈ Can have a withstand voltage value half that of the rectifier diodes Da to Dd of the rectifier circuit of FIG. That is, the rectifying diode D in the rectifying circuit of FIG.₁ ~ D₈ A low withstand voltage diode having a short recovery time t and fast recovery can be used. By using this fast recovery diode, the rectifier diode D₁ ~ D₈ Short circuit current I generated at recovery time t of_S Becomes negligible and the short circuit current I_S The effect on the load side of the rectifier is greatly suppressed, and the rectifier circuit can be operated at a higher frequency.

By increasing the frequency of the rectifier circuit in FIG. 1, the pair of high-frequency transformers T ₁ and T ₂ and the reactor L ₁ are downsized and the cost is reduced. The rectifier circuit of FIG. 1 uses a total of eight rectifier diodes D _{1 to} D ₈ which is twice the rectifier circuit of FIG. 5, but since the diode is a semiconductor module, The size and cost problems due to the increase in the number can be ignored.

The high-voltage high-frequency rectifier circuit shown in the second embodiment of FIG. 3 is characterized in that a bypass circuit 4 for the circulating current is connected in parallel to the output rectifier unit 2 of the rectifier circuit of FIG. The bypass circuit 4 is a circuit in which a supersaturation reactor L ₂ is connected in series to the cathode side of the high breakdown voltage diode D _H. High voltage diode D _H is placed in the same forward direction as the rectifier diode D ₁ to D ₈ of the output rectifying unit 2.

In the rectifier circuit of FIG. 3, the output voltage V _DC shown in FIG. 4 (b) is obtained with the AC input voltage V ₁ shown in FIG. 4 (a) and supplied to the DC load 3. In the section m where the AC input voltage V _{1 is} zero volt, the shunt current flows by shunting in the forward direction of the 4-series diode series of the output rectifying unit 2 and the bypass circuit 4. At this time, since the ON voltage of one high breakdown voltage diode D _H of the bypass circuit 4 is equivalently lower than the ON voltage of the 4-series diode series of the output rectifying unit 2, the circulating current is concentrated in the bypass circuit 4. Flow, output There is almost no flow in the rectifier 2.

Further, when the AC input voltage V ₁ fluctuates from zero volt to the plus or minus side, a short-circuit current instantaneously flows in the opposite direction only during the recovery time of the high breakdown voltage diode D _H. Here, by using, for the oversaturation reactor L ₂ of the bypass circuit 4, an impedance that blocks a short-circuit current that flows during the recovery time of the high breakdown voltage diode D _H , the short-circuit current does not flow in the bypass circuit 4. As a result, in the rectifier circuit of Fig. 3, there is almost no short-circuit current flow during the recovery time peculiar to the diode, the influence of the recovery time of each diode can be ignored, and it is even easier to increase the frequency of the rectifier circuit. become.

The present invention is not limited to the above-described embodiment, and for example, by increasing the number of high-frequency transformers for boosting the AC input voltage to three or more, and reducing the rectifier diode in the bridge circuit directly connected to each high-frequency transformer. It is also possible to achieve voltage conversion and fast recovery.

[0023]

[Effect of device]

 As in the present invention, the AC input voltage is boosted by a plurality of high-frequency transformers, each of which is full-wave rectified by a bridge circuit, and the DC voltage of the bridge circuits is added to supply a DC high voltage to the DC load. By doing so, a fast recovery diode with a low withstand voltage and a short recovery time can be applied to the rectifier diode of each bridge circuit, and the rectifier circuit can have a higher frequency. In addition, the high frequency realized the high frequency transformer and reactor of the rectifier circuit, and the cost reduction, and it has excellent versatility that can be effectively used for DC / DC converters and high frequency link type DC / AC inverters. A high-voltage high-frequency rectifier circuit can be provided.

In addition, by connecting in parallel a bypass circuit for a circulating current composed of a series circuit of a high breakdown voltage diode and a supersaturation reactor to an output rectification section which is a series circuit of a plurality of bridge circuits, the AC input voltage is changed from zero volt to a positive voltage or a positive voltage. When it fluctuates to the negative side, the short-circuit current that flows instantaneously only during the recovery time of the rectifier diode flows intensively in the bypass circuit, and this flow is blocked by the oversaturation reactor of the bypass circuit, resulting in the rectifier circuit. Since the short-circuit current does not flow into the circuit, the influence of the short-circuit current on the load can be ignored and the high-frequency high-frequency rectifier circuit can be made even higher in frequency.

[Brief description of drawings]

FIG. 1 is a high-voltage high-frequency rectifier circuit diagram showing a first embodiment of the present invention.

2 is a waveform diagram of voltage and current of the rectifier circuit of FIG.

FIG. 3 is a high voltage high frequency rectifier circuit diagram showing a second embodiment of the present invention.

FIG. 4 is a waveform diagram of voltage and current of the rectifier circuit of FIG.

FIG. 5: Conventional high-voltage high-frequency rectifier circuit diagram

6 is a waveform diagram of voltage and current of the rectifier circuit of FIG.

FIG. 7 is a circuit diagram of the rectifier circuit of FIG. 5 at a circulating current.

FIG. 8 is a circuit diagram of the rectifier circuit of FIG. 5 at a short-circuit current.

[Explanation of symbols]

2 Output rectifier 3 DC load V ₁ AC input voltage T ₁ , T ₂ high frequency transformer B ₁ , B ₂ bridge circuit D _{1 to} D ₈ rectifier diode 4 bypass circuit _DH high voltage diode L ₂ supersaturation reactor

Claims (2)

[Scope of utility model registration request] 1. A plurality of high-frequency transformers for boosting an AC input voltage, and a plurality of 4-rectifier diode bridge circuits for full-wave rectifying the boosted AC voltage in each high-frequency transformer are connected in series to form an external direct current. A high-voltage high-frequency rectifier circuit having an output rectifier connected to a load. 2. The high-voltage high-frequency rectifier circuit according to claim 1, wherein a bypass circuit for a circulating current, which is composed of a series circuit of a high breakdown voltage diode and a supersaturating reactor, is connected in parallel to the output side of the output rectifying unit.