JP3110294B2 - Buck-boost converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step-up / step-down converter, and more particularly to an electrode power supply including a high-voltage power supply for a traveling-wave tube used in a power amplifying device, as a DC stabilized power supply circuit.
The present invention relates to a current feedback type buck-boost converter which is generated based on AC conversion of a DC output of a converter and rectification / smoothing processing thereof and which stabilizes an output voltage by negative feedback control.

[0002]

2. Description of the Related Art Generally, in a high-voltage power supply for a traveling-wave tube that performs a current feedback type negative feedback control using a buck-boost converter, as shown in FIG. 2B and step-up transformer 3 to perform AC conversion and step-up, and after rectifying and smoothing by helical electrode rectifying / smoothing circuit 4 and collector electrode rectifying / smoothing circuit 5, helical electrode 8, collector electrode 9, cathode electrode 10 and anode electrode. A stabilized high voltage is output to each of the eleven electrodes.

[0003] Further, for the anode electrode 11, an anode power supply circuit 6 and an anode ON (ON / OFF for controlling the application of the output of the anode power supply circuit 6 to the anode electrode 11 under the control of a sequence control circuit 12). on)/
Power is supplied by the OFF (off) circuit 7. In a traveling wave tube having an anode electrode, when the anode voltage is turned off, the traveling wave tube turns off the beam current.
In this state, the load is light for the power supply, and the output voltage rises abnormally due to the peak charge of the capacitors in the two high-voltage rectification / smoothing circuits.

[0004] For this reason, particularly for a helical voltage requiring stability, a series regulator 1 is required in a high voltage circuit.
6, a dummy resistance load 17 is provided to suppress an increase in output voltage.

[0005]

In the above-mentioned conventional buck-boost converter as a power supply circuit for a traveling-wave tube, when the anode voltage is not applied to the traveling-wave tube, the beam current does not flow and the load becomes light, so that the rising of the step-up transformer 3 is started. The response becomes insufficient braking, and an overshoot occurs in the transformer output voltage. Further, the rectifying / smoothing circuit 4 for the helix electrode and the rectifying / smoothing circuit 5 for the collector electrode each operate as a capacitor input type circuit.
The peak voltage of the overshoot of the output voltage is charged, and the output voltage of the circuit rises to almost 1.5 times that at the time of the steady load.

On the other hand, in such a current feedback type buck-boost converter, the transfer characteristics for the same ON duty (duty) between a light load and a heavy load corresponding to when the anode voltage is turned off and on are significantly different. When the feedback control is performed to cope with the full load condition, the operation becomes unstable.

Among the high-voltage output voltages for traveling-wave tubes output from the buck-boost converter, the helix power supply voltage is required to be stable. In order to solve the above-mentioned problem, as shown in FIG. Rectification / smoothing circuit 4
In this case, a dummy resistance load 17 is connected to the output to supply a bleeder current to suppress the peak charge, or the series regulator 16 reduces the output voltage.

However, since these methods are applied on the high voltage circuit side, the circuit scale becomes large, and further, since the voltage is high, even a small amount of bleeder current causes the dummy resistance load 1 to be reduced.
However, there is a problem in that an internal loss of several tens of watts is generated in the 7 or the series regulator 16 and a reduction in power supply efficiency is inevitable.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a simple configuration having two main and auxiliary converters corresponding to heavy loads and light loads when the anode voltage is applied on and off . An object of the present invention is to provide a buck-boost converter capable of greatly improving stability and efficiency.

[0010]

The present invention has the following means in order to achieve the above object. That is, a first configuration of the present invention relating to a step-up / step-down converter is that a DC output of a converter as a DC stabilized power supply circuit is AC-converted and applied to a step-up transformer, and the output is rectified and smoothed to provide a power supply for a traveling wave tube. A buck-boost converter that generates
A main converter for controlling the on / off of the operation in conjunction with the on / off of the application of the anode voltage to the traveling wave tube to perform power sharing for a steady load in an on state, and power sharing for a light load when the anode voltage is off an auxiliary converter that performs the said main converter
The auxiliary converter is connected to the buck-boost transformer on the primary winding side.
It has a configuration provided with two series of step-up / step-down converters by a word OR connection .

A second configuration of the present invention has a configuration in which, in the first configuration, the auxiliary converter is always set to an operating state.

A third configuration of the present invention has a configuration in which, in the first or second configuration, AC conversion of the outputs of the main converter and the auxiliary converter is performed by an inverter.

[0013]

Next, the present invention configured as described above will be described. 2. Description of the Related Art A conventional current feedback type buck-boost converter for supplying necessary power to a helix, a collector, an anode and a cathode of a traveling wave tube converts an output of one converter into an AC by an inverter or the like as shown in FIG. After boosting this with a boost transformer,
The rectification / smoothing process is performed and the voltage is applied to each electrode.

In this case, the anode electrode voltage of the traveling wave tube is turned on / off in accordance with the flow / non-flow of the beam current, and this creates a heavy load state and a light load state. In the current feedback type buck-boost converter, the transfer characteristics at the same ON duty under such heavy load and light load are remarkably different, and correspond to all load conditions including both heavy and light load states based on negative feedback control. If it tries, operation instability will be unavoidable.

Therefore, in the conventional buck-boost converter, particularly for the helix power supply voltage which is required to be stabilized,
A series regulator and dummy resistance load (bleeder resistance) are interposed on the output side of the rectification / smoothing circuit to stabilize the voltage.

However, since such stabilization must be performed entirely on the high voltage circuit side, the current situation is that the circuit scale is increased and power supply efficiency is reduced due to unnecessary power consumption. Therefore, in the present invention, ON / OFF of the application of the anode electrode voltage of the traveling wave tube, that is, a main load and an auxiliary load, which share two load states corresponding to the beam current ON / OFF of the traveling wave tube, namely, a heavy load state and a light load state. By providing the two converters, a series regulator and a dummy resistor load are not required, thereby simplifying the circuit scale and ensuring improvement in power supply efficiency.

In this case, the auxiliary converter to be newly installed corresponding to the light load condition has an extremely low load of at most 1% as compared with the main converter. A much smaller circuit configuration is possible.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention. The configuration of the embodiment shown in FIG. 1 includes a main converter 1 for heavy load directly related to the present invention, a sequence control circuit 12A, an auxiliary converter 14 for light load and always kept in operation, The output of the two converters is ORed with the input of the inverters 2A and 2B.
Power OR diode 1 that enables connection
3A and 13B, and the same inverter 2 as the conventional example of FIG.
A, 2B, a step-up transformer 3, a helical electrode rectifying / smoothing circuit 4, a collector electrode rectifying / smoothing circuit 5, an anode power supply circuit 6, and an anode ON / OFF circuit 7. Of these components, those having the same reference numerals as those of the conventional example shown in FIG. 2 have the same content, and therefore detailed description thereof will be omitted.

Next, the operation of this embodiment will be described.
When a high voltage is applied, the anode ON / OFF circuit 7 is in an OFF operation state under the control of the sequence control circuit 12A. At this time, since the beam current of the traveling wave tube does not flow as the load of the power supply, the output power is less than 1% of the full load. In this case, the sequence control circuit 12A
Of the anode ON / OFF signal 1201 of
The operation of the main converter 1 is stopped.

Therefore, in this state, only the auxiliary converter 14 which is always in operation is operating, and its power capacity is small enough to supply the power capacity when the beam current of the traveling wave tube is OFF. Set to capacity. As a result, the power source impedance at the time of light load can be significantly increased as compared with the case of the prior art, the insufficient braking of the step-up transformer 3 can be suppressed, and the rectifying / smoothing circuit 4 for the high-voltage side helix electrode and The peak charge of the capacitors in the two rectifying / smoothing circuits of the rectifying / smoothing circuit 5 for the collector electrode is also suppressed.

When a beam current starts to flow in the traveling wave tube by the ON control by the anode ON / OFF signal 1201 from the sequence control circuit 12A, the anode ON / OFF is started.
The signal 1201 causes the main converter 1 connected to the auxiliary converter 14 to be operable in parallel with the power OR diodes 13A and 13B to start operation so that a power capacity corresponding to a steady load can be obtained.

When the main converter 1 starts operating and supplies each electrode voltage of the traveling wave tube, the output of the auxiliary converter 14 is also transmitted by the power OR connection of the power OR diodes 13A and 13B to the step-up transformer 3. However, since the operation sequence lags behind the output of the main converter 1 and is significantly lower in level, no problem occurs in normal operation.

Further, by providing the load sharing with the two main and auxiliary converters, a light load state does not exist for any of the converters, and a dummy resistance load or a series circuit corresponding to an abnormal increase in the output voltage is provided. No regulator is required.

Incidentally, the auxiliary converter 1 is different from the prior art.
However, since the power capacity is extremely small as described above, it can be realized with a circuit configuration much smaller than the countermeasure on the high voltage side in the related art.

[0025]

As described above, the present invention relates to a step-up / step-down converter for supplying a power supply voltage for a traveling wave tube. By providing power to the load with two converters, the operation range required for each converter can be limited, and stable operation can be obtained.
In addition, since there is no light load condition for any converter, a dummy resistance load or a series regulator to prevent an abnormal rise of the output voltage is not required, and the effect that the simplification of the high voltage circuit and the high efficiency can be easily realized can be realized. Have.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a step-up / step-down converter according to one embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional buck-boost converter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main converter 2A, 2B Inverter 3 Step-up transformer 4 Rectifier / smoothing circuit for helix electrode 5 Rectifier / smoothing circuit for collector electrode 6 Anode power supply circuit 7 Anode ON / OFF circuit 8 Helix electrode 9 Collector electrode 10 Cathode electrode 11 Anode electrode 12, 12A Sequence control circuit 13A, 13B Power OR diode 14 Auxiliary converter 15 Converter 16 Series regulator 17 Dummy resistance load

Claims (3)

(57) [Claims] 1. A step-up / step-down converter for converting a DC output of a converter as a DC stabilized power supply circuit into an AC voltage, applying the DC output to a step-up transformer, rectifying and smoothing the output to generate a power supply for a traveling wave tube, A main converter for controlling the on / off of the operation in conjunction with the on / off of the application of the anode voltage to the traveling wave tube to perform power sharing for a steady load in an on state, and power sharing for a light load when the anode voltage is off And a two-system buck-boost converter with an auxiliary converter for performing
And the auxiliary converter are on the primary winding side of the step-up / step-down transformer.
2. A step-up / step-down converter comprising two series of step-up / step-down converters by power OR coupling . 2. The step-up / step-down converter according to claim 1, further comprising a configuration in which the auxiliary converter is always set to an operating state. 3. The step-up / step-down converter according to claim 1, further comprising a configuration in which an AC conversion of the outputs of the main converter and the auxiliary converter is performed by an inverter.