JP2615932B2 - High voltage DC power supply - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage DC power supply used for aging vacuum tubes and the like.

[Conventional technology]

As shown in FIG. 4, a previously proposed example of a high-voltage DC power supply device on which the present invention is based (see Japanese Patent Application No. 62-10078) is shown in FIG.
The AC voltage supplied from the commercial power supply is converted into n converters CN.
_{1 to} CN _n independently convert to a DC voltage, and the DC voltages output from the _n converters CN _{1 to} CN _n are independently converted into the same amplitude by the _n inverters IN _{1 to} IN _n at the same period and the same amplitude. To convert the square wave AC voltage output from the _n inverters IN _{1 to} IN _n into insulation and voltage matching by the coupling transformers TR _{1 to} TR _n. respectively full-wave rectified by the full-wave rectifier DB ₁ to DB _n on the further additive synthesis each voltage after full wave rectification, the resulting combined voltage in the reactor L and consisting of a capacitor C ripple removing filter F It was configured to remove ripples by passing through and apply the obtained final DC voltage to a load such as a vacuum tube.

In this case, the n inverters IN _{1 to} IN _n are each configured to generate a rectangular wave AC voltage having a rest period between the positive half wave and the negative half wave. Then, the output terminals of the n-number of inverter IN ₁ to IN _n are respectively connected to the primary side of the n coupling transformer TR ₁ to Tr _n, n bonds transformer TR ₁ to Tr _n
The AC terminals of the n full-wave rectifier DB ₁ to DB _n are respectively connected to the secondary side, the DC-side terminals of the n full-wave rectifier DB ₁ to DB _n are cascade connected, the n-number Full-wave rectifier DB ₁
Ripple removal filters F at both ends of the cascade of ~ DB _n
Is connected, and the final DC voltage at the output of the ripple removing filter F is applied to the load.

Further, with the sum of the rest period of the square wave AC voltage output from n number of inverters IN ₁ to IN _n is set equal to the half of the output period of the n-number of inverter IN ₁ to IN _n, n number The output phases of the _n inverters IN _{1 to} IN _n are set so that the idle periods of the rectangular wave AC voltages output from the inverters IN _{1 to} IN _n do not overlap. In setting this, it is necessary to pay attention to the following points. That is, the value of the sum of the minimum period wherein the inverter IN ₁ to IN _n required by the output period of the inverter IN ₁ to IN _n
It is necessary to set the number so that it is smaller than 1/2.
That is, for example, an inverter IN ₁ minimum rest period to IN _n when the A ₁ to A _{n, respectively, A 1 <a 1 A 2} <a 2 ‥‥‥ A n <a n becomes quiescent period a ₁ ~a in _n, with respect to the output frequency f of the inverter iN ₁ to iN _n, the n-number of inverters configured to be _{a 1 + a 2 + ... +} a n = 1 / 2f. Incidentally, setting as in the above equation, because dead time to one cycle of the output of the inverter IN ₁ to IN _n is 2 times.

Further, the inverters IN _{1 to} IN _n provide B /
(N-1) voltage can be output.

Further, the rectangular wave AC voltage of the output of the inverter IN ₁ to IN _n, by adjusting with the output DC voltage of the converter CN ₁ -CN _n in phase control, the conduction of each switching element of the inverter IN ₁ to IN _n The width can be changed without changing the width.

In the case of the proposed example, the filter F for removing ripples is theoretically unnecessary, but actually, the inverter IN _1.
~ In _n operation, output phase shift due to output switching time, temperature and other characteristics, full-wave rectifier DB
_Since some ripple components due to the overlap angle of _{1 to} DB _n remain, they are often provided to remove these residual ripple components. The capacity may be sufficiently small, and the DC energy stored in the ripple removing filter F can be suppressed to a small value.

In this high-voltage DC power supply device, _if the maximum output voltage of each of the _n inverters IN _{1 to} IN _n is 500 V and the turn ratio of the coupling transformers TR _{1 to} TR _n is 1:20 as in the conventional example, In order to set the final DC voltage to be obtained from the output side of the ripple removing filter F to 40 KV, for example, n = 5. In the case where it is necessary to output a voltage higher than this, ask converter CN ₁ -CN _n, inverters IN ₁ to IN _n, increasing the combined number n of the full-wave rectifier DB ₁ to DB _n each final DC voltage I just need.

Here, FIG. 5 shows a time chart of each part in the high-voltage DC power supply device configured to obtain a final DC voltage of 40 KV with n = 5. In FIG. 5, (a) to (e)
Rectangular wave voltage V ₁ ~V ₅ output from the inverter IN ₁ to IN ₅ is
The frequency is, for example, 1 KHz, that is, the cycle is 1 mse
At c, there are pause periods T _{1 to} T ₅ of 100 μsec for every 500 μsec of a half cycle, and the amplitudes V _{1M to} V _5M are 500 V, respectively. Also,
(F) to (j) show output voltages V _{6 to} V of full-wave rectifiers DB _{1 to} DB _5.
10 and their amplitudes V _{6M to} V _10M are each ₁₀ KV,
Each time T ₀ (500 μsec) has a pause period T _{6 to} T ₁₀ of 100 μsec. (K) represents the combined voltage V ₁₁ obtained across the cascade of full-wave rectifier DB ₁ to DB _5, the voltage value V _11A
Has become 40KV.

According to the high-voltage DC power source device of this previously proposed example, the n-number inverter IN ₁ from to IN _n output period of the total n-number of inverter IN ₁ to IN _n rest period of the square wave AC voltage outputted In addition to setting them equal to 1/2, the output phases of the _n inverters IN _{1 to} IN _n are set so that the rest periods of the rectangular wave AC voltages output from the _n inverters IN _{1 to} IN _n do not overlap. As a result, any one of the _n inverters IN _{1 to} IN _n is always stopped, and the rectangular wave AC voltage output from the _n inverters IN _{1 to} IN _n is boosted and rectified. Ripple in the combined voltage obtained by adding and combining can be almost eliminated, and the filter F for removing ripple can be an extremely small-capacity filter which can remove residual ripple. Therefore, the DC energy stored in the ripple removing filter F becomes small. For example, even if the vacuum tube flashes during the aging of the vacuum tube, the flash current is very short due to the DC energy stored in the ripple removing filter F. It is shorter and the vacuum tube is prevented from being broken.

Incidentally, rest period of the inverter IN ₁ to IN _n are in the above description was identical, there is no need to set the dead time to the same, the sum of the suspension period of the output cycle of the inverter IN ₁ to IN _n 1 It is enough to make it equal to / 2.

Further, in the above-mentioned proposed example, each of the inverters IN _{1 to} IN _{n has} a 1
Although so as to sequentially shifting the output phase for each base, it may be shifting the output phase of the sequential inverter IN ₁ to IN _n for each plurality.

[Problems to be solved by the invention]

In this high-voltage DC power supply, n inverters
Each of the switching elements constituting IN _{1 to} IN _n has a variation in switching time and a variation in ON voltage, and the magnitudes of the positive half-wave and the negative half-wave of the output rectangular wave AC voltage are not the same, The square wave AC voltage sometimes contained a DC component.

Thus, when included a DC component into a rectangular wave AC voltage output from the inverter IN ₁ to IN _n, that coupling transformer TR ₁ to Tr _n of the rectangular wave AC voltage is applied is polarized excitation Become.

As such a structure for preventing the polarized excitation of coupling transformer TR ₁ to Tr _n, positive half wave and negative half-wave of the pulse width of the rectangular wave AC voltage output from the inverter IN ₁ to IN _n It is conceivable to perform a minute correction of. However, to correct the pulse width, the inverter IN ₁ the sum of the pause period ~I
Off the fact that reducing the ripple equal to half of the output period of the N _n, fine correction of n full-wave rectifier DB ₁ to DB the pulse width to a DC voltage appears across the cascade connection of _n And the ripple associated with the filter appears, and the capacitance of the ripple elimination filter must be increased.

FIG. 6 shows that when a high-voltage DC power supply is configured using _five inverters IN _{1 to} IN ₅ , the square-wave AC voltage output from the inverter IN ₁ has no positive half-wave or negative half-wave. 4 shows a time chart of each part of the apparatus of FIG. 4 when an equilibrium exists, and (a) to (k) show (a) to (a) of FIG.
(K) respectively. FIG. 6 (a),
The broken lines in (f) and (k) correspond to those shown in FIGS.
It shows the same waveforms as (f) and (k).

Comparing FIG. 6 with FIG. 5, it is clear that the ripple increases when the pulse width is corrected.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a high-voltage DC power supply device capable of preventing the demagnetization of a coupling transformer without increasing a ripple.

[Means for solving the problem]

The high-voltage DC power supply according to the present invention is provided with n (n is an integer of 2 or more) inverters that generate a rectangular-wave AC voltage having an idle period at the same cycle and the same amplitude, and the output terminals of the n inverters Are connected to the primary sides of n coupling transformers, respectively, and the AC sides of n full-wave rectifiers are respectively connected to the secondary sides of the n coupling transformers. The DC side is cascaded.

Further, there are provided n output imbalance detecting means for detecting imbalances of the positive half-wave and the negative half-wave of the outputs of the n inverters, respectively, according to the outputs of the n output imbalance detecting means. And n control means for changing the voltage drop between both ends of each of the switching devices of the n inverters when conducting to balance the positive half-wave and the negative half-wave of the output of the n inverters. ing.

Then, the sum of the rest periods of the rectangular wave AC voltages output from the n inverters is set to be equal to 1/2 of the output cycle of the n inverters, and the rectangular wave AC voltage output from the n inverters is set. The output phases of the n inverters are set so that the idle periods do not overlap.

[Action]

In the configuration of the present invention, the rectangular wave AC voltages respectively output from the n inverters are respectively insulated and boosted by the n coupling transformers, and then full-wave rectified by the n full-wave rectifiers and added. They are combined and applied to the load.

At this time, the sum of the rest periods of the rectangular wave AC voltage output from each of the n inverters is set so as to be equal to 1/2 of the output cycle of the n inverters.
Since the output phase of each of the n inverters is set so that the rest periods of the rectangular wave AC voltages output from the n inverters do not overlap, any one of the n inverters is always in operation. Always stops, and there is almost no ripple in the combined voltage obtained by boosting, rectifying and adding and combining the rectangular wave AC voltages output from the n inverters.

In addition, the output imbalance detecting means detects the imbalance of the positive half-wave and the negative half-wave of the output of the n inverters, respectively, and the n control means respectively operates the n output imbalance detecting means. Changing the voltage drop between both ends of each of the switching elements of the n inverters when conducting according to the output of
The peak values of the positive half-wave and the negative half-wave of the rectangular wave AC voltage respectively output from the n inverters are changed. As a result, the positive half-wave and the negative half-wave of the outputs of the n inverters are balanced, and the polarization excitation of the n coupling transformers is prevented. In this case, the peak values of the positive half wave and the negative half wave of the rectangular wave AC voltage output from the n inverters are adjusted to balance the positive half wave and the negative half wave of the outputs of the n inverters. Therefore, the ripple does not increase.

〔Example〕

One embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the high-voltage DC power supply generates n-wave rectangular AC voltages having an idle period between a positive half-wave and a negative half-wave with the same period and the same amplitude.
The switching elements of the inverters IN _{1 to} IN _n (where n is an integer of 2 or more) are configured by transistors. Specifically, for example, an inverter IN ₁ connects the switching positive half wave output transistor Q _11, Q ₁₄ and negative for half-wave output switching transistor Q _12, Q ₁₃ like a bridge, the positive side half Wave output switching transistor Q ₁₂ ,
Q ₁₄ and the negative half-wave output switching transistors Q _12, Q ₁₃
And diodes D ₁₁ , D ₁₄ , D ₁₂ , and D ₁₃ are connected in anti-parallel. Similarly, the inverter IN ₂ includes switching transistors Q ₂₁ and Q ₂₄ for positive half-wave output, switching transistors Q ₂₂ and Q ₂₃ for negative half-wave output, and diodes D ₂₁ and D ₂₁ .
_24, is composed of a D _22, D _23, the inverter IN _n is a positive for the half-wave output switching transistor Q _n1, Q _n4, a switching transistor for negative half-wave output Q _n2, Q _n3, diode D _n1 , D _n4 , D _n2 , D _n3 .

Then, n DC current transformers CT ₁ are connected to the primary windings of the coupling transformers TR _{1 to} TR _n connected to the output terminals of the inverters IN _{1 to} IN _n.
Each interposed a to CT _n, the output current, that the n of n-number in the secondary side of the n DC current transformer CT ₁ to CT _n inverter IN ₁ to IN _n coupling transformer TR ₁ to Tr _n is provided an output imbalance detection means DT ₁ to DT _n for detecting positive half wave and negative half wave area difference of the primary current (imbalance), respectively.

Further, n number of output imbalance detection means DT ₁ to DT _n n stand inverter according to the output of the IN ₁ to IN respective switching transistors for the positive-side half wave output of the _{n Q 14, Q 24, ...} Q
switching transistor Q ₁₃ for _n4 and negative half-wave output,
By increasing or decreasing the base current of Q ₂₃ ,... Q _n3 and changing its on-voltage drop, the positive half-wave and the negative half-wave of the square wave AC voltage output from the _n inverters IN _{1 to} IN _n are changed. balance the positive side half wave and negative half-wave to the primary current of the positive half wave and negative half wave of the differential area to each zero by changing the peak value of n coupling transformer TR ₁ to Tr _n There are provided n sets of base current control means CR ₁₁ , CR ₁₂ , CR ₂₁ , CR ₂₂ ,..., CR _n1 , CR _n2 .

 Other configurations are the same as those in FIG.

In this high-voltage DC power supply, n coupling transformers
TR ₁ to Tr positive half-wave and area difference of negative half-wave of the primary current of _n a is n output imbalance detection means DT ₁ to DT _n detect respectively, the n base current control means CR ₁ ~ Each of the positive half-wave output switching transistors Q ₁₄ , Q ₂₄ ,... Of each of the _n inverters IN _{1 to} IN _n has CR _n corresponding to the output of the _n output imbalance detecting means DT _{1 to} DT _n . The base currents of the switching transistors Q ₁₃ , Q ₂₃ ,..., Q _{n 3} for Q _n4 and the negative half-wave output are increased or decreased to change the on-voltage drop, and rectangles output from the _n inverters IN _{1 to} IN _n The peak values of the positive half wave and the negative half wave of the wave AC voltage are changed. As a result, n-number of coupling transformer TR ₁ to Tr positive half-wave and area difference of the negative half wave and becomes zero respectively the positive side half wave and negative half-wave of the primary current of _n is balanced, polarized excitation of the n coupling transformer TR ₁ to Tr _n is prevented. In this case, the peak _values of the positive half-wave and the negative half-wave of the square wave voltage of the _n inverters IN _{1 to} IN _n are adjusted to adjust the positive side of the primary current of the _n coupling transformers TR _{1 to} TR _n. Since the half-wave and the negative half-wave are balanced, the ripple does not increase.

Here, the operations of the inverter IN ₁ , the output imbalance detecting means DT _{1, the} base current controlling means CR _{1 and the} like will be described in detail.

In this high-voltage DC power supply, the primary current of the coupling transformer TR ₁ is detected by a DC current transformer CT _1, the secondary output of the DC current transformer CT ₁ is input to the output imbalance detection means DT _1. Then, in the output imbalance detection means DT _1, the positive side area difference of half wave and negative half wave of the primary current of the coupling transformer TR ₁ is detected. Further, the output of the output imbalance detection means DT ₁ is input to the base current control circuit CR ₁₂ through a low-pass filter LPF _1, also the low-pass filter LPF ₁ and sign inversion circuit
Input through NT ₁ to the base current control circuit CR _11.

On the other hand, the positive half-wave output switching transistor Q ₁₁ ,
Q _14, the switching transistor Q ₁₂ for negative half-wave output, Q ₁₃
The base, the gate pulse is inputted from the gate pulse generator GP _1, positive for half-wave output switching transistor Q _11, Q _14, negative half wave output switching transistor Q ₁₂ in response to the gate pulse, Q ₁₃ are each performing the switching operation. At this time, the base of the switching positive half wave output transistors Q ₁₄ and a negative half-wave output switching transistor Q _13, the base current control circuit C
A base current increase / decrease control signal for increasing / decreasing the base current is input together with a gate pulse from R ₁₁ and CR _12, and a positive half-wave output switching transistor Q ₁₄ and a negative half-wave output are provided in accordance with the base current increase / decrease control signal. oN voltage during conduction of use switching transistor Q ₁₃ would change. As a result, the peak values of the positive half wave and the negative half wave of the rectangular wave AC voltage output from the inverter IN ₁ rise and fall, and the area of the positive half wave of the primary current of the coupling transformer TR ₁ and the negative half wave The area of the wave is controlled the same. Therefore, the coupling transformer
The primary side of the TR ₁ will flow positive side half-wave and the primary current equal the area of the negative half wave, polarized excitation of coupling transformer TR ₁ is prevented.

Next, a third specific structure of the output imbalance detection means DT ₁
Description will be made based on the drawings.

The output imbalance detection means DT ₁ is composed of a positive half-wave area calculating circuit KS ₁₁ and the negative half-wave area calculating circuit KS ₁₂ and the synchronization circuit SY ₁ subtractor HK ₁ Tokyo. In operation, the synchronization circuit SY ₁ creates a sample signal synchronized with the output of inverter IN _1, based on the secondary output of the DC current transformer CT _1. Further, the positive half-wave area calculating circuit KS _11, based on the sample signal supplied from the synchronizing circuit SY _1, the positive half-wave area of the primary current of the coupling transformer TR ₁ is calculated for each cycle, the Each calculation result is output for the next one cycle. Further, the negative half-wave area calculation circuit KS ₁₂ calculates the area of the negative half-wave of the primary current of the coupling transformer TR ₁ based on the sample signal given from the synchronization circuit SY _1, and calculates the calculation result. Each signal is output for the next one cycle.

Subtractor HK ₁ the output of the negative half-wave area calculating circuit KS ₁₂ from the output of the positive half-wave area calculating circuit KS ₁₁ subtracts, and outputs the subtraction result. Therefore, from the subtractor HK _1, so that the area difference signal corresponding to the difference between the positive half-wave and the area of the negative half-wave of the primary current of the coupling transformer TR ₁ is outputted in one cycle delay.

The area difference signal output from the output imbalance detection means DT ₁ is input to the base current control circuit CR ₁₂ mentioned above through a low-pass filter LPF _1, also the base current control through the low-pass filter LPF ₁ and the sign determination circuit NT ₁ It will be input to the circuit CR _11.

The operation of the other circuit units is the same as that of FIG. 4, and a description thereof will be omitted.

In the above embodiment, for the detection of magnetic bias of the coupling transformer TR ₁ to Tr _n, the difference in area between the positive half wave and the negative half-wave of the primary current of the coupling transformer TR ₁ to Tr _n Although the a configuration obtaining the may be configured to determine the difference in area between the positive half wave and the negative half-wave of the secondary current of the coupling transformer TR ₁ to Tr _n, short inverter
It is sufficient if the imbalance between the positive half-wave and the negative half-wave of the outputs of IN _{1 to} IN _n can be obtained directly or indirectly.

〔The invention's effect〕

According to the high-voltage DC power supply of the present invention, the imbalance between the positive half-wave and the negative half-wave of the output of the inverter is detected by the output imbalance detecting means, and the control means responds to the output of the output imbalance detecting means. The peak values of the positive half-wave and the negative half-wave of the square wave AC voltage output from the inverter are changed by changing the voltage drop between both ends of the respective switching elements of the inverter when the switching elements are turned on. Since the positive half-wave and the negative half-wave of the output are balanced, the bias excitation of the coupling transformer can be prevented without increasing the ripple.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of a high-voltage DC power supply device according to an embodiment of the present invention, FIG. 2 is a specific circuit diagram of a peripheral portion of an inverter, and FIG. 3 is a specific configuration of an output imbalance detecting means. FIG. 4 is a block diagram showing the configuration of the already proposed example of the high-voltage DC power supply, FIG. 5 is a time chart of each part in FIG. 4, and FIG. 6 is an imbalance in the primary current of the coupling transformer. 5 is a time chart of each part in FIG. 4 in a certain case. IN _{1 to} IN _n ... Inverter, TR _{1 to} TR _n ... Coupling transformer, DB
_{1 to} DB _n ... full-wave rectifier, DT _{1 to} DT _n ... output imbalance detection means, CR _{1 to} CR _n ... base current control means

Claims (1)

(57) [Claims] 1. An n-unit (n is an integer of 2 or more) that generates a rectangular wave AC voltage having a rest period with the same cycle and the same amplitude.
, An n number of coupling transformers each having a primary side connected to the output end of the n number of inverters, and an alternating current side connected to the secondary side of the n number of coupling transformers, and the dc side is cascaded. N connected full-wave rectifiers, n output imbalance detecting means for detecting imbalances of the positive half-wave and the negative half-wave of the outputs of the n inverters, respectively, and the n output imbalances The voltage drop between both ends of the n inverters when the respective switching elements are turned on is changed in accordance with the output of the balance detection means, and the positive half wave and the negative half wave of the outputs of the n inverters are changed. Comprising n control means for balancing, and setting the total of the idle periods of the rectangular wave AC voltage output from each of the n inverters to be equal to 1/2 of the output cycle of the n inverters, The n inverters A high-voltage DC power supply device in which the output phases of the n inverters are set such that the rest periods of the rectangular wave AC voltages output from the inverters do not overlap.