JPH0630308B2 - Memory type negative feedback power supply - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a memory type negative feedback power supply device for supplying a current to a load, for example, an alternating current magnetization characteristic of an iron core such as a toroidal core or a cut core type iron core. It is used for an iron core testing device for conducting the test of, a power supply device for a rectifier circuit load, a power supply device for a strain current load, and the like.

[Conventional technology]

In order to test the alternating current magnetization characteristics of the exciting current, eddy current loss and hysteresis loss of a large number of toroidal iron cores, it is necessary to apply windings to the iron core each time the test is performed. That is, as shown in FIG. 7, the primary winding W is attached to the iron core 1.
₁ and secondary winding W ₂ of the winding, loosen winding these windings when the test is completed. In order to omit such complicated winding work, it is possible to envisage a method of facilitating the attachment / detachment of the windings W ₁ , W ₂ by means of the connector-shaped contacts CW ₁ , CW ₂ shown in FIG. 7. However, in the actual design of a transformer, etc., originally, the thickness of the winding is made as large as possible to reduce the DC resistance of the winding and the number of windings is usually very large. , The voltage drop and heat generation due to the winding resistance component are sufficiently small, but in the case of FIG.
Since the arrangement space of CW ₁ and CW ₂ is limited, the winding thickness is small and the number of windings is small. As a result,
The test exciting current flowing through the primary winding must be increased, and it is strongly affected by the resistance of the winding and the contacts. Incidentally, in FIG. 6, the connector contact CW ₁ ,
The upper and lower contacts of CW ₂ are separated when the iron core is inserted and tested (measured)
By making them contact with each other, the work of winding the iron core becomes unnecessary.

The toroidal iron core test apparatus having the test winding shown in FIG. 7 is conventionally connected to the primary winding W ₁ with an input AC power source and an AC ammeter, and to the secondary winding W ₂ with an AC voltmeter. A power meter is connected between the primary winding W ₁ and the secondary winding W ₂ to measure the primary current I _p near the saturation magnetic flux density, which is one of the AC magnetization characteristic tests of the iron core. The iron loss is measured based on it. The iron loss is measured with a power meter.

[Problems to be Solved by the Invention]

However, for example, the equivalent DC resistance of the primary winding W ₁ varies with the heat generated by the excitation current I _p, the contact DC resistance of the connector contacts CW ₁ is unstable and varies depending on the state of the connector contacts CW ₁ Therefore, the equivalent AC resistance of the primary winding W ₁ also changes depending on the saturation characteristics of the iron core. Therefore, the secondary winding W
_The output voltage E _s generated at ₂ fluctuates greatly. further,
In the vicinity of the saturation magnetic flux density of the iron core, there is instantaneous primary winding W decrease in the equivalent AC resistance of ₁ due to abnormal current locally generated in the AC cycle, Therefore, generated in the secondary winding W ₂ The waveform of the output voltage E _s is significantly distorted. These fluctuations and distortions are that the magnetic flux in the iron core fluctuates and is distorted.
This is an extremely defective test for an iron core, which should have a constant and correct AC magnetic flux. Therefore, even if the voltage E _s generated in the secondary winding W ₂ is corrected by adjusting the voltage of the AC power supply for each iron core so that the output voltage E _s of the secondary winding W ₂ is constant, Distortion remains in the waveform, that is, the output voltage E _s , and along with this, the peak current portion of the exciting current I _p is suppressed, and correct measurement is impossible.

Therefore, the applicant has already negatively fed back a part of the output voltage E _s of the secondary winding W _{2 to} the primary winding W ₁ side in an analog manner, thereby stabilizing the output voltage E _s . (See Japanese Patent Application No. 62-018625). That is, as shown in FIGS. 8 and 9 (equivalent circuit diagram of FIG. 8), 1
Connect the winding W input AC power source 2 and the AC ammeter 3 to _1, to connect the secondary winding W across the AC voltmeter 4 _2, primary winding W ₁ and secondary winding W ₂ A power meter W is connected between the differential amplifier 5, the differential amplifier 5, the feedback resistor 6, and the phase adjusting circuit 7.
A negative feedback loop consisting of Here, _assuming that the ratio of the input voltage of the input AC power supply 2 and the output voltage E _s when there is no negative feedback loop is the overall amplification factor A ′, it is assumed that A ′ = 100 to 20 and a large variation occurs. Next, considering the feedback circuit, when the feedback ratio F is set to 0.99 by the feedback resistor 6, the output voltage E _s becomes (E ₁ is the voltage of the AC power supply 2, which is 1 V in this case), Becomes In this way, the fluctuation of the output voltage E _s becomes small. Therefore, the equivalent DC resistance value R due to the connector contact CW _1
p , even if the equivalent AC resistance value R _zp and the DC resistance value R _{c of the} primary winding W ₁ fluctuate, almost no adjustment of the input AC voltage is required. As a result, the magnetic flux waveform in the iron core 1, that is, the output voltage. The distortion of E _s also decreases as shown in FIG. The stability of the output voltage E _s can be improved by increasing the amplification factor of the amplifier 5 to increase the feedback factor F. However, when the feedback factor F is increased, oscillation occurs due to the influence of leakage reactance of the winding. A phenomenon usually occurs, which can be prevented to some extent by adjusting the resistance and / or the capacitor of the phase adjustment circuit 7.

However, in the device of the analog type negative feedback system shown in FIG. 8, for example, an iron core made of grain-oriented silicon steel plate can secure sufficient practical accuracy up to a magnetic flux density of about 17,000 gauss, but the magnetic flux density is close to saturation, for example. If an extremely distorted current wave of 18,000 to 20000 gauss is passed and high precision and stability are required, the feedback rate and amplification rate must be increased. However, if these values are raised, the limit point that reaches the oscillation phenomenon is inevitably reached. That is, if the amplification factor is 1 or more and the phase shift in the negative feedback loop is 180 ° or more, the oscillation condition is satisfied, but the phase shift is usually generated in the relatively high frequency range due to the influence of the capacitance. However, it is difficult to completely adjust even by the adjustment of the phase adjusting circuit 7 described above, and it becomes even more difficult if an inductance component (a winding and a leakage inductance between windings) is added to the negative feedback loop. Therefore, even if the analog negative feedback is performed, the output voltage E _s is still high at the high magnetic flux density as described above.
The waveform distortion and instability of ∘ remains. That is, in the analog type negative feedback loop, when the above-mentioned oscillation condition is satisfied, the oscillation is triggered by some stimulus (micro noise etc.) and the positive feedback is repeated at a specific cycle (usually 10 KHz to 1 MHz), In a moment, the amplitude grows at an accelerating rate, and as shown in FIG. 10, the oscillation state occurs.

Therefore, an object of the present invention is to make the winding work by utilizing the connector-like contact point unnecessary, and also to achieve an extremely high magnetic flux density.
Even if the direct current resistance value due to the contact, the equivalent alternating current resistance value and the direct current resistance value of the primary winding W ₁ fluctuate, it is not necessary to adjust the input voltage for each iron core, and there is no distortion in the magnetic flux waveform for stable and accurate measurement An object of the present invention is to provide a power supply device for an iron core testing device.

Another object of the present invention is to provide a power supply device used as a power supply device for a rectifier circuit load or a power supply device for a distorted current load.

[Means for Solving the Problems]

Means for solving the above problems are shown in FIGS. 1A and 1B.

FIG. 1A shows a power supply device for supplying a current to a load, for example, a test device for iron core 1. The basic sine wave generating means generates a basic sine wave voltage E _o . Error voltage detecting means detects a voltage error ΔE between the fundamental sinusoidal voltage E _o and the load of the output voltage E _s for example core 1 of the secondary winding voltage E _s, the storage means stores the voltage error ΔE It is delayed by one cycle of the basic sine wave voltage E _o . The adding means adds the delayed voltage error ΔE ′ to the basic sine wave voltage E _o , and the input current supplying means supplies the input current I _p corresponding to the addition result of the adding means to the load, for example, the secondary winding W of the iron core 1. ₂ is supplied.

In FIG. 1B, addition means for adding the delayed voltage error ΔE ′ to the voltage error ΔE is added between the voltage error detection means and the storage means in the constituent elements of FIG. 1A.

[Action]

According to the means shown in FIG. 1A, in order to prevent repetition of high-frequency positive feedback, a waveform to be negatively fed back for one cycle of the basic sine wave is stored and delayed by one cycle to perform negative feedback. That is, as shown in FIG. 2, as a waveform to be negatively fed back, only a waveform error (voltage error) is taken out and stored (A), and the waveform is corrected by negatively feeding back by shifting by one cycle (B). This makes the phase 180 ° in the high frequency range.
Even if there is the above deviation, as shown in FIG. 3, the positive feedback is divided for each cycle of the basic sine wave, so that growth and oscillation due to repetition do not occur.

According to the means shown in FIG. 1B, the waveform error is further stored in addition to the stored waveform one cycle before, and the operation of negatively feeding it back is repeated in the next cycle. Therefore, the accumulated waveform error is added to the basic sine wave, and the feedback factor F can be increased almost infinitely. For example, the return rate increases as follows: 1st cycle 0.9 2nd cycle 0.99 3rd cycle 0.999 4th cycle 0.9999.

〔Example〕

FIG. 4 is a block circuit diagram showing a first embodiment of the memory type negative feedback power supply device according to the present invention, which is applied to an iron core test device. In FIG. 4, control is performed by digital processing. That is, 401 is a control unit (CPU) that controls each unit, 402 is a frequency changeover switch, and 403 is a voltage setting switch (for example, a digital switch).

404 fundamental sine wave generating circuit for generating a basic sine wave E _o (R
OM) and 405 are voltage adjusting circuits (multipliers) for adjusting the voltage for adjusting the output voltage of the basic sine wave generating circuit 404. In this case, the basic sine wave E generated by the basic sine wave generation circuit 404
The frequency of _o is changed by the control unit 401 depending on whether the frequency changeover switch 402 is on or off. That is, the control unit 401 sends a clock signal of a predetermined frequency according to the ON / OFF of the frequency changeover switch 402 to the basic sine wave generation circuit 404. The control unit 401 also sends a voltage multiplier α according to the contents of the voltage setting switch 403 to the voltage adjusting circuit 405, and as a result, the voltage adjusting circuit 405 multiplies the digital value of each basic sine wave E _{o by} the voltage multiplier α. Then, a new basic sine wave E _o ′ is generated.

Reference numerals 406 and 407 are delay memories for adjusting the delay time so that the total delay time is one cycle of the basic sine wave E _o , and are, for example, bidirectional memories in which writing / reading can be performed simultaneously. That is, the delay memories 406 and 407 are
It operates according to the write address WA and the read address RA of the address counters 406a and 407a which are incremented by the clock signal of the control unit 401. In this case, the delay memory
It is determined by a value obtained by multiplying the difference (RA-WA) between the write address WA and the read address RA of 406 (407) by the cycle of the clock signal generated by the control unit 401. The subtraction circuit 408 calculates a voltage error ΔE between the fundamental chord wave E _o ′ and the output voltage E _s between the secondary windings W ₂ which is A / D converted by the A / D converter 412. The adder circuit 409 adds the voltage error ΔE delayed by one cycle to the basic sine wave E _o ′. This addition result is D / A converted by the D / A converter 410, and the power amplifier 411 determines the primary winding W ₁ based on this analog value.
To the input current I _p .

In this way, the output voltage E _s of the secondary winding W ₂ is negatively fed back to the input current I _p by the negative feedback loop circuit (406, 408, 407, 412), and the waveform to be negatively fed back is one cycle of the basic sine wave E _o. Only delayed. As a result, as shown in FIG. 5, the output voltage E _s is stable even in a high magnetic flux density state.

FIG. 6 is a block circuit diagram showing a second embodiment of the storage type negative feedback power supply device according to the present invention, which is different from the components shown in FIG. 4 in that a delay memory 601, an address counter 601a,
And an adder circuit 602 is added. In this case, the total delay time of the three delay memories 406, 407, 601 is adjusted to be one cycle of the basic sine wave E _o . Therefore, according to the second embodiment, as compared with the first embodiment,
Since the voltage error ΔE ′ to be negatively fed back is accumulated, the feedback rate F can be made extremely large.

Further, in the above-described embodiment, the primary winding W ₁ and the secondary winding W ₂ may be other than the connector type, and
Even if the number of turns is one each, a sufficiently stable and highly accurate test (measurement) is possible. Moreover, the arrangement and arrangement of the contacts can be set freely. Furthermore, the primary winding W ₁ and the secondary winding W ₂ do not have to have the same number of turns.

Further, according to the present invention, by using the analog negative feedback system shown in FIG.

Furthermore, the present invention can be applied to a cut-core type iron core testing device, and can also be applied to a power supply device for a rectifier circuit load and a distorted current load, in addition to the power supply device for an iron core testing device.

〔The invention's effect〕

As described above, according to the present invention, in the case of the iron core test device, the winding work for each iron core is omitted, and even if the magnetic flux density is extremely high, a correct and stable test (measurement) is performed without adjusting the input voltage. ) Can be done. In addition, the feedback rate can be extremely increased.

[Brief description of drawings]

1A and 1B are block circuit diagrams showing the basic configuration of the present invention, FIGS. 2 and 3 are diagrams for explaining the operation of the present invention, and FIG. 4 is a memory type negative feedback power supply device according to the present invention. 5 is a block circuit diagram showing a first embodiment of the present invention, FIG. 5 is a diagram showing output characteristics in FIG. 4, and FIG. 6 is a block circuit showing a second embodiment of a storage type negative feedback power supply device according to the present invention. Fig. 7, Fig. 7 is a diagram showing an example of a test winding, Fig. 8 is a circuit diagram showing an embodiment of the previously proposed iron core test apparatus, Fig. 9 is an equivalent circuit diagram of Fig. 8, and Fig. 10 FIG. 4 is a diagram for explaining a problem to be solved by the present invention. 1: Iron core 2: AC power supply 3: AC ammeter 4: AC voltmeter W: Power meter W ₁ : Primary winding W ₂ : Secondary winding I _p : Excitation current E _s : Output voltage 404: Basic sine generation Circuit 405: Voltage adjustment circuit 406,407,601: Delay memory 408: Subtraction circuit 409,602: Addition circuit

Claims (2)

[Claims] 1. A power supply device for supplying a current and a voltage to a load, comprising a basic sine wave generating means for generating a basic sine wave voltage (E _o ), the basic sine wave voltage and an output voltage of the load. Error voltage detection means for detecting a voltage error (ΔE) from (E _s ), storage means for storing the voltage error and delaying it by one cycle of the basic sine wave voltage, and the delayed voltage error Negative feedback memory system comprising: an addition means for adding (ΔE ′) to the basic sine wave voltage; and an input current supply means for supplying an input current (I _p ) according to the addition result of the addition means to the load. Power supply. 2. The adding means for adding the delayed voltage error (ΔE ') to the voltage error (ΔE) is provided between the voltage error detecting means and the delay means. Memory type negative feedback power supply.