JPH0816257A - Voltage regulator - Google Patents

Abstract

PURPOSE:To obtain a power saving type voltage regulator for regulating only the excess/shortage of load voltage by executing highly efficient and highly accurate voltage control on the primary side comparatively small in a current flowing to a series transformer in a device which is arranged between an AC power supply and an AC electric instrument and regulates the operation voltage of the AC electric instrument to be an optionally set voltage value. CONSTITUTION:A power supply 1 is connected between input terminals 2-1, 2-2, the input terminal 2-1 is connected to one end of a secondairy winding 4-2 of a series transformer 4 and the other end thereof is connected to an output terminal 6-1 connected to a load 7. The AC power supply input terminal 2-2 is connected to an output terminal 6-2 and the output side of a regulator 11 is connected to the primary winding 4-1 of the transformer 4 through a filter 12 and a polarity switch 9 as a means for optionally changing E2. Input voltage Es is connected to the input side of the regulator 11 through the transformer 4, the switch 9 and the filter 10. An output voltage setter 14 and a controller 13 are connected to the regulator 11 so as to control the regulator 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of adjusting the voltage supplied from a commercial power source or other AC power source to a load such as AC electrical equipment to an arbitrarily set voltage value.
The present invention relates to a compact, lightweight, highly accurate, low cost voltage regulator.

[0002]

2. Description of the Related Art A conventional voltage regulator controls the entire voltage and current required by the load to supply power to the load, and a large filter for shaping the waveform distortion due to the switching method. However, the size and weight are large, resulting in high manufacturing cost and poor responsiveness. Further, self-heating due to poor conversion efficiency is also a problem.

[0003]

SUMMARY OF THE INVENTION Therefore, the present invention significantly improves the drawbacks of conventional voltage regulators such as size, weight, conversion efficiency, resulting increase in manufacturing cost, electromagnetic noise, etc. The purpose is to bring economic effects to.

[0004]

To achieve the above object, in a voltage regulator according to the present invention (a first invention according to claim 1), one of an AC power supply input terminal and a secondary winding of a series transformer is provided. Connect with one end of. The other end of the secondary winding of the series transformer is connected to one of output terminals to which a load is connected. The other of the AC power input terminals and the other of the output terminals are connected. The output side of the amplifier is connected to the primary winding of the series transformer. As means for arbitrarily varying the primary voltage (hereinafter abbreviated as E1) of the series transformer, the output side of a multiplication type digital-analog converter (hereinafter abbreviated as DA) is connected to the input side of the amplifier. The reference power source input terminal of the DA is connected to the output side of the polarity switcher as a means for switching between step-up and step-down of an input voltage (hereinafter abbreviated as Es) applied to the AC power source input terminal. The secondary side of the transformer is connected to the input side of the polarity switch. The primary side of the transformer is connected to the AC power input terminal. The signal output from the output voltage setting device is connected to the digital input terminal of the DA in order to make E1 an arbitrary size by the analog output of the DA. In order to switch the polarity of E1, the polarity switching signal of the output voltage setting device is connected to the polarity switching device.

In order to achieve the above object, in the voltage regulator of the present invention (the second invention according to claim 2), one of the AC power supply input terminals and one end of the secondary winding of the series transformer are connected. ,
The other end of the secondary winding of the series transformer is connected to one of the output terminals to which the load is connected. The other of the AC power input terminals and the other of the output terminals are connected. As means for shaping the waveform of the primary voltage of the series transformer (hereinafter abbreviated as E1), the output side of the post-stage filter is connected to the primary winding of the series transformer. As a means for arbitrarily changing the E1,
The output side of the regulator is connected to the input side of the post filter.
The input side of the regulator is connected to the output side of the pre-filter. The input side of the pre-stage filter is connected to the output side of the polarity switching device as means for switching between step-up and step-down of the input voltage (hereinafter abbreviated as Es) applied to the AC power supply input terminal. The input side of the polarity switch is connected to the AC power input terminal. To make E1 an arbitrary size,
The pulse width modulation signal output from the output circuit section of the control section is connected to each bidirectional AC switch element constituting the adjuster. The setting signal of the output voltage setting device is connected to the input side of the PWM circuit unit. In order to switch the polarity of E1, the switching signal of the controller output circuit section is connected to the polarity switch.

To achieve the above object, in the voltage regulator of the present invention (the third invention according to claim 3), one of the AC power supply input terminals and one end of the secondary winding of the series transformer are connected. ,
The other end of the secondary winding of the series transformer is connected to one of the output terminals to which the load is connected. The other of the AC power input terminals and the other of the output terminals are connected. The output side of the post-stage filter is connected to the primary winding of the series transformer as a means for shaping the waveform. The output side of the polarity switch is connected to the input side of the post-stage filter as means for switching between step-up and step-down of the input voltage (hereinafter abbreviated as Es) applied to the AC power supply input terminal. The output side of the inverter section is connected to the input side of the polarity switch as a means for arbitrarily changing the primary voltage (hereinafter abbreviated as E1) of the series transformer. The input side of the inverter section is connected to the output side of the pre-stage filter. The output side of the converter section is connected to the input side of the pre-stage filter. The input side of the converter unit is connected to the AC power input terminal. In order to make E1 an arbitrary size, the pulse width modulation signal output from the output circuit section of the control section is connected to each bidirectional AC switch element constituting the inverter section. Set the output voltage setting device setting signal to P
Connect to the input side of the WM circuit section. In order to switch the polarity of E1, the switching signal of the controller output circuit section is connected to the polarity switch.

[0007]

The operation of the voltage regulator of the first aspect of the present invention having the above construction will be described below. Load voltage applied to the load (hereinafter E
The voltage L is abbreviated as the sum or difference between Es and the secondary voltage of the series transformer (hereinafter abbreviated as E2). E2 or E1 is varied by the analog output of DA connected to its primary winding through an amplifier. Es is connected to the reference power source input signal of the DA through the polarity switcher and the transformer, and a signal that differs only in amplitude from Es is changed at a constant rate of the set value output by the output voltage setter. Is a voltage of the same frequency that differs from Es only in amplitude, and a voltage of the same frequency as Es can be applied to the load. When the load voltage EL applied to the load is set to a high value, the polarity switching device is set by the output voltage setting device so that the phases of Es and E2 are the same, so that EL is the sum of Es and E2. It becomes the voltage of. Further, the output voltage setting device D is used to increase E2.
If the digital input of A is set, the analog output of DA will be larger and EL will also be larger. Further, if only the digital input of DA is set so that E2 becomes smaller while the polarity remains unchanged, EL becomes smaller.
When the load voltage EL applied to the load is set to a low value, the polarity switching device is set by the output voltage setting device so that the phase difference between Es and E2 is 180 °. It becomes the voltage of the difference. In the range where Es is larger than E2, EL is further reduced by setting the digital input of DA with the output voltage setting device so that E2 becomes larger. If only the digital input of DA is set so that E2 becomes smaller while the polarity remains unchanged, EL becomes larger. Es is always E
If it is clear that it is larger or smaller than L, the polarity switching can be omitted since no polarity switching is required. Further, the polarity of E1 or E2 can be inverted by omitting the polarity switching converter and utilizing the bipolar output function of DA.

The operation of the voltage regulator of the second invention having the above structure will be described below. The load voltage (hereinafter abbreviated as EL) applied to the load is the sum or difference voltage of Es and the secondary voltage (hereinafter abbreviated as E2) E2 of the series transformer. E2 is varied by the output of the regulator connected to the primary winding through the polarity switch and the post-stage filter. The PWM control signal of the controller outputs a sine wave output voltage equivalent to Es to the primary winding through the post-filter by switching each bidirectional AC switch element of the regulator at a constant ratio. be able to. When the load voltage EL applied to the load is set to a high value, EL is set to the sum of Es and E2 by setting the polarity switcher with the output voltage setting device so that Es and E2 have the same phase. It becomes a voltage. further,
In the switching operation of the regulator by the PWM control signal, if the on time of the switch is made longer and the off time is made shorter, the output of the regulator becomes larger, and as a result, E2
Also grows. As a result, EL also becomes larger. Further, if the switching operation of the regulator is made longer and the ON time of the switch is shortened while the polarity switching device is in the same state, the output of the regulator becomes smaller and, as a result, E2 also becomes smaller. As a result, EL becomes smaller. When the load voltage EL applied to the load is set to a low value, the polarity switching device is set by the output voltage setting device so that the phase difference between Es and E2 is 180 °. It becomes the voltage of the difference.
In the range where Es is larger than E2, when the switching operation of the regulator by the PWM control signal is made such that the on time of the switch is made longer and the off time is made shorter, the output of the regulator becomes larger and, as a result, E2 also becomes larger. . As a result, EL becomes smaller. Further, if the switching operation of the regulator is made longer and the ON time of the switch is shortened while the polarity switching device is in the same state, the output of the regulator becomes smaller and, as a result, E2 also becomes smaller. This makes EL larger.

The operation of the voltage regulator of the third invention having the above construction will be described below. The load voltage (hereinafter abbreviated as EL) applied to the load is the sum or difference voltage of Es and the secondary voltage of the series transformer (hereinafter abbreviated as E2). E
2 is variable by the output of the inverter unit connected to the primary winding through the polarity switch and the post-stage filter. The PWM control signal of the control unit switches the bidirectional AC switch elements of the inverter unit at a constant ratio to generate a sine wave output voltage equivalent to Es through the polarity switch and the post-stage filter. Can be output to the winding. When the load voltage EL applied to the load is set to a high value, Es and E
By setting the polarity switching device with the output voltage setting device so that the phase of 2 becomes the same phase, EL becomes Es and E2.
It becomes the sum voltage of. Further, when the switching operation of the inverter section by the PWM control signal is made such that the on-time of the switch is made longer and the off-time is made shorter, the output of the inverter section becomes large and, as a result, E2 also becomes large.
As a result, EL also becomes larger. If the switching operation of the inverter section is made longer and the ON time of the switch is shortened while the polarity switcher remains as it is, the output of the inverter section becomes smaller and, as a result, E2 also becomes smaller. As a result, EL becomes smaller. When the load voltage EL applied to the load is set to a low value, the polarity switching device is set by the output voltage setting device so that the phase difference between Es and E2 is 180 °. It becomes the voltage of the difference. Es
When E is larger than E2, when the switching operation of the inverter unit by the PWM control signal is made to have a long ON time and a short OFF time of the switch, the output of the inverter unit becomes large and, as a result, E2 also becomes large. As a result, EL becomes smaller. If the switching operation of the inverter section is made longer and the ON time of the switch is shortened while the polarity switcher remains as it is, the output of the inverter section becomes smaller and, as a result, E2 also becomes smaller. This makes EL larger.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(First Embodiment) The voltage regulator of the first embodiment is an embodiment of the first invention, and as shown in FIG. 1, a power supply 1 is provided between AC power supply input terminals 2-1 and 2-2. And the input terminal 2-1 and one end of the secondary winding 4-2 of the series transformer 4 are connected. The other end of the secondary winding 4-2 of the series transformer 4 is loaded with a load 7
Is connected to the output terminal 6-1. Input terminal 2-
2 and the output terminal 6-2 are connected. Primary winding 4-1
To the output side of the amplifier 3-2. As a means for arbitrarily changing E1, the output side of DA3-1 is connected to the input side of amplifier 3-2. As a means for switching the input voltage Es between step-up and step-down, the output side of the polarity switch 9 is set to DA3.
Connect to -1 reference power input terminal. The secondary side of the transformer 8 is connected to the input side of the polarity switcher 9. Input terminal 2-
The primary side of the transformer 8 is connected to 1 and 2-2. DA3-1
The signal output from the output voltage setting unit 5 is connected to the digital input terminal of the DA 3-1 in order to make E1 have an arbitrary size by the output of. In order to switch the polarity of E1, the polarity switching signal of the output voltage setting device 5 is connected to the bidirectional AC switch of the polarity switching device 9. Output terminals 6-1, 6
-2 is connected to the load 7 to supply power to the load.

Next, the operation of the above embodiment will be described.
The input voltage Es as shown in FIG. 4A passes from the input terminal 2 to the secondary winding via the transformer 8, the polarity switching transformer 9, the regulator 3 and the primary winding 4-1 of the series transformer 4. The voltage of E2 is induced in the output voltage, and the combined voltage of E2 and Es is applied to the load 7 connected to the output terminal 6. The load voltage EL applied to the load 7 can be represented by the following two equations depending on the state of the polarity switch 9 when the input voltage is Es and the secondary voltage of the series transformer is E2. When the input voltages E1 and E2 are in phase: EL = Es + E2 When the phase difference between the input voltages E1 and E2 is 180 °: EL = Es-E2 E2 is the amplifier 3 connected to its primary winding 4-1. -2, the voltage of the primary winding is E1, the multiplication type digital-analog converter DA3-1 and the amplifier 3-2 are provided.
Is Q, the turn ratio of the secondary winding to the primary winding of the transformer 8 is a1, and the primary winding 4-1 of the series transformer 4 is
E2 can be expressed by the following equation, where a2 is the winding ratio of the secondary winding 4-2 to. E2 = a2 × E1 Here, E1 is the output of the amplifier 3-2 (E1 = Q × a1 ×
Since Es), E2 becomes E2 = a2 * Q * a1 * Es, and as a result, the above EL is EL = Es + a * Q * Es or EL = Es-a * Q, where a = a1 * a2.
It can be represented by × Es. As can be seen from this equation, EL can be adjusted by changing the combined amplification factor Q, and EL can be made larger or smaller than Es by switching the polarity of the polarity switch 9. That is, the EL adjustment range is (1-a * Q) * Es to (1 + a * Q) * Es. Next, the operation of the above embodiment will be described based on this equation. When the load voltage EL applied to the load is set to a high value, the polarity switcher 9 is set by the output voltage setting device 5 so that the phases of Es and E2 are the same, so that EL is the sum of Es and E2. (EL = (1 + a × Q) ×
Es). Further, when the digital input of DA3-1 is set so that a2 is constant and E2 is increased by the output voltage setting unit 5, the combined amplification factor Q is increased and EL is also increased. If only the digital input of DA3-1 is set so that E2 becomes smaller while the polarity remains the same, the combined amplification factor Q becomes smaller and becomes smaller than EL. When the load voltage EL applied to the load is set to a low value, the polarity switching device 9 is set by the output voltage setting device 5 so that the phase difference between Es and E2 is 180 °. Difference ((1-a × Q) × Es). In the range where Es is larger than E2, if the digital input of DA3-1 is set by the output voltage setting unit 5 so that E2 becomes large, the combined amplification factor Q becomes large and EL becomes smaller. If only the digital input of DA3-1 is set so that E2 becomes smaller while the polarity remains the same, the combined amplification factor Q becomes smaller and EL becomes larger. When it is clear that the load voltage EL is always higher or lower than the input voltage Es, the polarity switching device 9 can be omitted since the polarity switching is not necessary. Further, the connection position of the polarity switching device is different from that of the present embodiment, and is between the input terminal 2 and the transformer 8, between the DA 3-1 and the amplifier 3-2 or the amplifier 3-.
It can be anywhere between the second winding and the primary winding 4-1. Next, another embodiment will be described. The configuration of the main circuit is shown in FIG. 1 as an embodiment, but as shown in FIG. 2, a multiplier / divider 3-3 is installed in place of the multiplication type digital-analog converter DA3-1 of the adjuster 3, The output side of the polarity switching device 9 is connected to one input terminal of the multiplier / divider 3-3, and the multiplier / divider 3-
The set value of the output voltage setting device 5 is connected to the other input terminal of 3. The operation of the embodiment shown in FIG. 2 will be described by taking the case where the multiplier / divider 3-3 is used as a multiplier. The output voltage (set value) of the output voltage setting device 5 is EQ, the turns ratio of the secondary winding to the primary winding of the transformer 8 is a1, and the series transformer 4 is 1
When the winding ratio of the secondary winding 4-2 to the secondary winding 4-1 is a2, the secondary voltage E2 can be expressed by the following equation. E2 = a2 * E1 Here, E1 or the output of the amplifier 3-2 (E1 = EQ * a1
XEs), E2 becomes E2 = a2 * EQ * a1 * Es, and as a result, EL is EL = Es + a * EQ * Es or EL = Es-a *, where a = a1 * a2.
It can be expressed as EQ × Es. As can be seen from this expression, EL can be adjusted by changing the set value EQ of the output voltage setting device 5, and the polarity switching device 9
EL can be made larger or smaller than Es by switching the polarity of. That is, the EL adjustment range is (1-a * EQ) * Es to (1 + a * EQ) * Es, and the same voltage adjustment as in the first embodiment can be performed.

(Second Embodiment) The voltage regulator of the second embodiment is an embodiment of the second invention, and as shown in FIG. 3, a power supply 1 is provided between AC power supply input terminals 2-1 and 2-2. And the input terminal 2-1 and one end of the secondary winding 4-2 of the series transformer 4 are connected. The other end of the secondary winding 4-2 of the series transformer 4 is loaded with a load 7
Is connected to the output terminal 6-1. Input terminal 2-
2 and the output terminal 6-2 are connected. As a means for shaping the waveform of E1, the output side of the post-stage filter 12 is connected to the primary winding 4-1 of the series transformer 4. As a means for arbitrarily changing E1, the output side of the adjuster 11 is connected to the input side of the post-stage filter 12. The input side of the regulator 11 is connected to the front filter 1
Connect to the output side of 0. The input side of the pre-stage filter 10 is connected to the output side of the polarity switcher 9 as a means for switching the step-up or step-down of Es. Polarity switch 9 for input terminal 2
Connect the input side of. To make E1 an arbitrary size,
The pulse width modulation signals d1, d2, d3, and d4 output from the output circuit unit 13-1 of the control unit 13 are connected to the bidirectional AC switch elements forming the adjuster 11, respectively. The setting signal of the output voltage setting device 14 is connected to the input side of the PWM circuit unit 13-2. In order to switch the polarity of E1, the polarity switching signal of the output circuit section 13-1 of the control section is connected to the bidirectional AC switch of the polarity switch 9. Output terminals 6-1, 6
-2 is connected to the load 7 to supply power to the load.

Next, the operation of the above embodiment will be described.
The input voltage Es as shown in FIG. 4A passes from the input terminal 2 through the polarity switching device 9, the pre-stage filter 10, the regulator 11, the post-stage filter 12 and the primary winding 4-1 of the series transformer 4. Two
The voltage of E2 is induced in the next winding, and the combined voltage of E2 and Es is applied to the load 7 connected to the output terminal 6. The output of the regulator 11 has a distorted waveform as shown in FIG. 4 (b) due to the switching operation, is smoothed to the original sine wave by the post-stage filter 12, and is applied as the voltage E1 to the primary winding of the series transformer. The PWM control signals d1, d2, d3, and d4 of the control unit 13 are controlled by both the regulator 11 as a measure for suppressing abrupt changes in the voltage and current generated inside the switch circuit and the load due to the switching operation during energization. AC switch elements 11-1, 11-2, 11-
Nos. 3 and 11-4 are driven at the timing shown in FIG. As shown in FIG. 4C, the switch elements 11-1 and 11-2 are turned on and the switch elements 11-3 and 1 are turned on during the period Ton.
1-4 are turned off, and Es is the switching element 11- during that time.
It is applied to the primary winding 4-1 of the series transformer 4 through the post-stage filters 12 through 1 and 11-2. See also Toff
During the period, the ON operation and the OFF operation of the switch elements 11-1 and 11-2 and the switch elements 11-3 and 11-4 are inverted to each other, the switch elements 11-1 and 11-2 are turned off, and the switch element 11- 3 and 11-4 are turned on, and during that time E
s is blocked by the switch elements 11-1 and 11-2, and the input side of the post-stage filter 12 is the switch element 11-
It is short-circuited at 3, 11-4. In the next Ton period, the switching elements 11-1 and 11-2 and the switching element 11- are again provided.
3, 11-4 are mutually inverted and the same switching operation is repeated. In this way, the voltage Eout having a waveform obtained by PWM-switching Es as shown in FIG. 4B is applied to the input side of the post-stage filter 12, and the voltage E1 smoothed by the post-stage filter 12 is applied to the primary winding 4-. Given to 1.
In each period of Ton and Toff, the switching operation is performed in a two-step system in order to suppress a transient phenomenon at the time of switching. In the period Ton, 11-2 is turned on with a certain time delay after the switch element 11-1 is turned on, and when it is off, 11-1 is turned off with a certain time delay after the switch element 11-2 is turned off. A resistor or a reactor 11-5 that suppresses overvoltage or overcurrent is connected in series to the switch element 11-2, and the switching operation of the switch element 11-2 is performed while the switch element 11-1 is on. Then, abrupt changes in voltage and current during switching are suppressed.
In the period Toff, 11-4 is turned on with a certain time delay after the switch element 11-3 is turned on, and when the switch element 11-3 is off, 11-3 is turned off with a certain time delay after the switch element 11-4 is turned off.
A resistor or a reactor 11-6 that suppresses overvoltage and overcurrent is connected in series to the switch element 11-3,
When the switch element 11-3 is on, the switch element 11-3
The steep change in voltage and current during switching is suppressed by performing the switching operation of -4. The 2-step method of the switching operation described above may be 3-step or 4-step if necessary.
The number of steps can be increased. As the number of stages increases, the harmonic current and switching noise generated during switching are reduced. A one-stage system can also be used, in which case the switching element 11-1, the suppressing element 11-5, the switching element 11-3, and the suppressing element 11-6
Are removed from the regulator 11 and switch elements 11-2 and 1
Only 1-4 will be adjusted. In this case, when the two-way switches 11-2 and 11-4 are inverted from each other, the turn-on of each two-way switch can be slightly delayed so that the switches are simultaneously turned on and the power source is not short-circuited. The pre-stage filter 10 suppresses the influence of switching noise and harmonic current generated during the switching operation of the regulator 11 on the power supply line.

The load voltage EL applied to the load 7 can be expressed by the following two equations depending on the state of the polarity switch 9 when the input voltage is Es and the secondary voltage of the series transformer is E2. When the phases of the input voltages E1 and E2 are in phase: EL = Es + E2 When the phase difference of the input voltages E1 and E2 is 180 °: EL = Es-E2 E2 is a post-stage filter connected to its primary winding 4-1. 1
2 is given by the output of the regulator 11 through E1, the voltage of the primary winding is E1, the turn ratio of the secondary winding 4-2 to the primary winding 4-1 of the series transformer 4 is a, and the regulator 11 The voltage E1 (series transformer primary voltage) obtained by waveform-shaping the output of E2 and the regulator 11 can be expressed by the following equations, where Ton is the switch-on time and T is the cycle. E2 = a × E1 E1 = (TON / T) × Es Therefore, E2 becomes E2 = a × (TON / T) × Es, and as a result, the above EL is EL = Es + a × (TON / T) × Es or EL = It can be expressed as Es-a * (TON / T) * Es. As can be seen from this equation, EL can be adjusted by changing the ON time TON of the switch of the adjuster 11 by the PWM control signal, and EL can be made larger or smaller than Es by changing the polarity of the polarity switch 9. That is, the EL adjustment range is [1-a × (TON / T)] × Es to [1 + a ×
(TON / T)] × Es. Next, the operation of the above embodiment will be described based on this equation. When the load voltage EL applied to the load is set to a high value, the polarity switch 9 is set by the output voltage setter 14 so that the phases of Es and E2 are the same, so that EL is the sum of Es and E2. (EL = [1 + a × (T
ON / T)] × Es). Further, when a is constant and the ON time TON of the switch of the adjuster 11 is increased by the PWM control signal of the control unit 13, EL also increases. Further, if the ON time TON of the switch of the adjuster 11 is shortened by the PWM control signal while the polarity remains unchanged, EL also becomes smaller. Load voltage EL applied to the load
When is set to a low value, the phase difference between Es and E2 is 1
Set the polarity switch 9 to the output voltage setter 14 so that it becomes 80 °.
By setting with, EL is the difference between Es and E2 ([1
−a × (TON / T)] × Es). In the range where Es is larger than E2, a is constant and the ON time TON of the switch of the regulator 11 is controlled by the PWM control signal of the control unit 12.
The larger EL becomes, the smaller EL becomes. Further, if the ON time TON of the switch of the adjuster 11 is reduced by the PWM control signal while the polarity is kept as it is, EL becomes larger. If it is clear that EL is always larger or smaller than Es, the polarity switching converter 9 can be omitted since the polarity switching is not necessary. Further, the connection position of the polarity switching device 9 is different from that of this embodiment, and the pre-stage filter 10 and the adjuster 11 are provided.
, Between the regulator 11 and the post filter 12 or between the post filter 12 and the primary winding 4-1. A power transistor as a bidirectional AC switch element,
Field effect transistor (MOSFET), IGBT, G
A circuit incorporated by a power device such as TO or SIT can be used. The suppression elements 11-5 and 11-
6 can be a choke coil, a resistor or a capacitor, or a combination thereof. It is also possible to connect a snubber circuit or a surge absorbing element to the switch element or the circuit in order to suppress the surge voltage generated during the switching operation of the polarity switching device 9 or the regulator 11.

(Third Embodiment) The voltage regulator of the third embodiment is an embodiment of the third invention, and as shown in FIG. 5, a power supply 1 is provided between AC power supply input terminals 2-1 and 2-2. And the input terminal 2-1 and one end of the secondary winding 4-2 of the series transformer 4 are connected. The other end of the secondary winding 4-2 of the series transformer 4 is loaded with a load 7
Is connected to the output terminal 6-1. Input terminal 2-
2 and the output terminal 6-2 are connected. As a means for shaping the waveform of E1, the output side of the post-stage filter 12 is connected to the primary winding 4-1 of the series transformer 4. The output side of the polarity switch 9 is connected to the input side of the post-stage filter 12 as a means for switching the Es step-up or step-down. As a means for arbitrarily changing E1, the output side of the inverter unit 16 is a polarity switch 9
Connect to the input side of. The input side of the inverter unit 16 is connected to the output side of the pre-stage filter 10. The output side of the converter unit 15 is connected to the input side of the pre-stage filter 10. The input side of the converter unit 10 is connected to the input terminal 2. In order to make E1 an arbitrary size, the output circuit section 17-
The pulse width modulation signal output from the circuit 1 is connected to a bidirectional AC switch element that constitutes the inverter unit 16. The setting signal of the output voltage setting unit 14 is connected to the input side of the PWM circuit unit 17-2. In order to switch the polarity of E1, the switching signal of the controller output circuit 17-1 is connected to the bidirectional AC switch of the polarity switch 9. A load 7 is connected between the output terminals 6-1 and 6-2 to supply power source power to the load.

Next, the operation of the above embodiment will be described.
As shown in FIG. 4 (a), the input voltage Es is rectified and smoothed from the input terminal 2 by the converter unit 15 and the pre-stage filter 10 and converted into AC by the inverter unit 16, the polarity switching device 9, and the post-stage filter 12, and the series transformer. The voltage of E2 is induced in the secondary winding via the primary winding 4-1 of No. 4, and the combined voltage of E2 and Es is applied to the load 7 connected to the output terminal 6. The output of the inverter unit 16 has a waveform distorted by the switching operation, is smoothed to the original sine wave by the post-stage filter 12, and is applied to the primary winding of the series transformer as the voltage E1. The pre-stage filter 10 smoothes the rectified voltage and at the same time suppresses switching noise and harmonic current generated during the switching operation of the inverter unit 16 from affecting the power supply line. The load voltage EL applied to the load 7 can be represented by the following two equations depending on the state of the polarity switch 9 when the input voltage is Es and the secondary voltage of the series transformer is E2. When the phases of the input voltages E1 and E2 are in phase: EL = Es + E2 When the phase difference of the input voltages E1 and E2 is 180 °: EL = Es-E2 E2 is a post-stage filter connected to its primary winding 4-1. 1
Given by the output of the inverter section 16 through 2,
The voltage of the primary winding is E1, the primary winding 4-1 of the series transformer 4 is
Is a, the turn-on time of the inverter section 16 is Ton, and the cycle is T, and the cycle is T.
1 (series transformer primary voltage) can be expressed by the following equations, respectively. E2 = a × E1 E1 = (TON / T) × Es Therefore, E2 becomes E2 = a × (TON / T) × Es, and as a result, the above EL is EL = Es + a × (TON / T) × Es or EL = It can be expressed as Es-a * (TON / T) * Es. As can be seen from this equation, EL can be adjusted by changing the switch-on time TON of the inverter unit 16 by the PWM control signal, and EL can be made larger or smaller than Es by switching the polarity of the polarity switcher 9. That is, the EL adjustment range is [1-a × (TON / T)] × Es to [1 + a ×
(TON / T)] × Es. Next, the operation of the above embodiment will be described based on this equation. When the load voltage EL applied to the load is set to a high value, the polarity switching device 9 is set by the output voltage setting device 14 so that the phases of Es and E2 are in phase, so that EL is the sum of Es and E2. (EL = [1 + a × (T
ON / T)] × Es). Further, when a is constant and the PWM control signal of the control unit 17 increases the ON time TON of the switch of the inverter unit 16, EL also increases. Further, when the ON time TON of the switch of the inverter unit 16 is shortened by the PWM control signal while the polarity remains the same, EL also becomes smaller. When the load voltage EL applied to the load is set to a low value, the polarity switching device 9 is set by the output voltage setting device 14 so that the phase difference between Es and E2 is 180 °.
Difference ([1-a × (TON / T)] × Es). E
In the range where s is larger than E2, a is constant and the control unit 17
If the ON time TON of the switch of the inverter unit 16 is increased by the PWM control signal of, EL becomes smaller. Further, when the ON time TON of the switch of the inverter unit 16 is reduced by the PWM control signal with the polarity kept unchanged, EL becomes larger. If it is clear that EL is always larger or smaller than Es, the polarity switching converter 9 can be omitted since the polarity switching is not necessary.
Further, the connection position of the polarity switching device 9 may be different from that of this embodiment and may be between the post-stage filter 12 and the primary winding 4-1. Power transistors, field effect transistors (MOSFETs), IGBTs, GTOs, SITs as bidirectional AC switches
It can be a circuit using a power device such as.
A snubber circuit or a surge absorbing element may be connected to the switch element or the circuit in order to suppress a surge voltage generated during the switching operation of the polarity switching device 9 or the inverter section 16.

[0018]

The first invention, the second invention, and the above-described effect are achieved.
All of the third inventions add or subtract only the excess or deficiency voltage necessary for adjusting the required load voltage to the original AC power supply voltage for control, and in most applications, the primary of the special transformer. Since the current on the side is smaller than the load current, the capacity of the switch element installed on the primary side is correspondingly reduced, so the drawbacks of conventional voltage regulators are the size, weight, number of parts, conversion efficiency, and manufacturing using it. High costs and electromagnetic noise can be greatly improved. Therefore, it is possible to provide a small and lightweight voltage regulator which will be very economical and highly reliable in the future.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a voltage regulator according to the first invention.

FIG. 2 is a circuit diagram showing another embodiment of the voltage regulator according to the first invention.

FIG. 3 is a circuit diagram showing a second embodiment of the voltage regulator according to the second invention.

FIG. 4 is a waveform diagram by the voltage regulator according to the second invention.

FIG. 5 is a circuit diagram showing a third embodiment of the voltage regulator according to the third invention.

[Explanation of symbols]

1 is an AC power supply 2 is an AC power supply input terminal 3 is a regulator 3-1 is a multiplication type digital / analog converter 3-2 is an amplifier 3-3 is a multiplier / divider 4 is a series transformer 4-1 and 4-2 are Primary winding of series transformer 4 and 2 respectively
Next winding 5 is output voltage setting device 6 is output terminal 7 is load 8 is transformer 9 is polarity switching device 9-1, 9-2, 9-3, 9-4 is bidirectional AC switching device 10 Filter 10-1 is a choke coil 10-2 is a capacitor 11 is a regulator 11-1, 11-2, 11-3, 11-4 are bidirectional AC switch elements 12 is a filter 12-1 is a choke coil 12- 2 is a capacitor 13 is a control unit 13-1 is an output circuit unit 13-2 is a PWM circuit unit 14 is an output voltage setter 15 is a converter unit 16 is an inverter unit 17 is a control unit 17-1 is an output circuit unit 17-2 PWM circuit section

Claims (3)

[Claims] 1. An AC power supply input terminal is connected to one end of a secondary winding of a series transformer, and the other end of the secondary winding of the series transformer is connected to one of output terminals to which a load is connected. , The other side of the AC power supply input terminal and the other side of the output terminal are connected, the output side of the amplifier is connected to the primary winding of the series transformer, the primary voltage of the series transformer is arbitrary The output side of the multiplication type digital-analog converter is connected to the input side of the amplifier, and the polarity of the input voltage applied to the AC power supply input terminal is switched between the input side and the output side of the amplifier. The reference power source input terminal of the multiplication type digital-analog converter is connected to the output side of the switching unit, the secondary side of the transformer is connected to the input side of the polarity switching unit, and the transformer is connected to the AC power source input terminal. Connect the primary side of the Connecting the signal output from the output voltage setter to the digital input terminal of the multiplication type digital-analog converter in order to make the primary voltage of the series transformer have an arbitrary value by the analog output of the analog converter, A voltage regulator, wherein a polarity switching signal of an output voltage setting device is connected to the polarity switching device to switch the polarity of the primary voltage of the series transformer. 2. An AC power supply input terminal is connected to one end of a secondary winding of a series transformer, and the other end of the secondary winding of the series transformer is connected to one of output terminals to which a load is connected. And the other side of the AC power supply input terminal and the other side of the output terminal are connected, and the output side of the post-stage filter is connected to the primary winding of the series transformer as a waveform shaping means, As a means to arbitrarily change the primary voltage of
The output side of the regulator is connected to the input side of the post-stage filter, the input side of the regulator is connected to the output side of the pre-stage filter, and the switching of the step-up or step-down of the input voltage applied to the AC power supply input terminal is switched. As a means for performing the above, the input side of the pre-stage filter is connected to the output side of the polarity switch, the input side of the polarity switch is connected to the AC power supply input terminal, and the primary voltage of the series transformer is set to an arbitrary value. To size
The pulse width modulation signal output by the control unit is connected to each of the bidirectional AC switch elements constituting the adjuster, the setting signal of the output voltage setting unit is connected to the input side of the PWM circuit unit, and the series transformer A voltage regulator characterized in that a switching signal of the control unit output circuit unit is connected to the polarity switching unit to switch the polarity of the primary voltage. 3. An AC power supply input terminal is connected to one end of a secondary winding of the series transformer, and the other end of the secondary winding of the series transformer is connected to one of output terminals to which a load is connected. , The other side of the AC power supply input terminal and the other of the output terminal are connected, the output side of the post-stage filter is connected to the primary winding of the series transformer as a waveform shaping means, the AC power supply input As means for switching between step-up or step-down of the input voltage applied to the terminal, the output side of the polarity switch is connected to the input side of the post-stage filter, and as the means for arbitrarily changing the primary voltage of the series transformer,
The output side of the inverter unit is connected to the input side of the polarity switch, the input side of the inverter unit is connected to the output side of the pre-stage filter, the output side of the converter unit is connected to the input side of the pre-stage filter, In order to connect the input side of the converter section to the AC power supply input terminal and to make the primary voltage of the series transformer have an arbitrary size,
The pulse width modulation signal output from the control unit is connected to each bidirectional AC switch element of the inverter unit, the setting signal of the output voltage setting unit is connected to the input side of the PWM circuit unit, and the serial transformer primary A voltage regulator, wherein a polarity switching signal of the output voltage setting device is connected to the polarity switching device in order to switch the polarity of the voltage.