KR20130026952A - A digital electric power control device - Google Patents

Abstract

PURPOSE: A digital power controlling device is provided to stably provide power by minimizing influences to an outer environment through digitalizing entire structure of blocks converting AC commercial power into DC power. CONSTITUTION: A SCR(Silicon Controlled rectifier) block(120) rectifies AC commercial power and generates DC power. A measuring block(110) feedback inputs the measured value of a load of generated DC power. A phase calculating means(121) calculates a phase switching the SCR block. A clock pulse counting means(123) counts the clock pulse of a system clock. A digital comparator(125) generates a pulse generating signal when a clock pulse count corresponds to a result calculated at the phase calculating means. A pulse generating means(128) generates a pulse opening the SCR block according to the pulse generating signal of the digital comparator. [Reference numerals] (110) Measuring block; (112) Digital multimeter; (115) Digital filter; (120) SCR block; (121) Phase calculating means; (123) Clock pulse counting means; (125) Digital comparator; (127) Phase detector; (128) Pulse generating means

Description

Digital power control device {A Digital Electric Power Control Device}

The present invention relates to a digital power supply control device that performs digital control of a power supply device. More particularly, the present invention relates to a circuit for calculating an opening point of an SCR for rectifying an AC commercial power supply and generating a pulse at the opening point. By configuring the digital circuit, it is possible to control the power supply with high precision and accuracy by minimizing the influence of external noise environment, and to the digital power control device which can promote the safety of the operator when the initial reference value of the power control device is tuned.

The conventional power control apparatus shown in FIG. 1 is intended to supply a constant power source to a heater or various loads 11 regardless of an external influence, and to convert an AC commercial power source (for example, industrial 380V AC) into an SCR (Silicon Contrlled Rectifier, The same will be described below) to generate a DC power supply through the block 20.

The phase detector 21 of the conventional power control device performs zero cross detection of the AC commercial power input to the SCR block 20 and inputs it to the control means 22, and the CPU 15 loads 11 ) Is calculated from the measured values of the measurement block 12 for voltage and current, and is input to the control means 22 by calculating the turn-on time of the SCR for voltage stabilization, that is, the phase.

The control means 22 detects the input of the CPU 15, generates a voltage waveform corresponding to the CPU 15 calculation result and is synchronized with the zero intersection detected by the phase detector 21 and inputs it to the comparator 25. . The comparator 25 detects the SCR opening position by comparison with the reference wave and opens the SCR by inputting a pulse signal to the gate of the SCR.

However, the conventional power supply control device having the configuration as described above has the following problems.

As shown in FIG. 2, the information on the pulse generation position of the control means 22 is input to the comparator 25 as an analog voltage, and the comparator 25 itself is composed of an analog circuit so that a plurality of variable resistors are provided. The configuration used. Therefore, when a highly uniform voltage is supplied for a long time, such as the production of sapphire ingots, in the work process, the zero point of the variable resistor must be performed for at least 7 to 8 places during the operation of the power supply for initial tuning. As the work process is complicated, it requires not only a considerable time, but also requires highly skilled workers, and there is a risk of electric shock due to the need to adjust the zero point in the energized state of industrial power of 380V.

In addition, since the input of the comparator 25 is an analog voltage, and the comparator 25 is an analog electric circuit, as shown in FIG. 2, the comparator 25 detects a phase in comparison with a reference wave, thereby generating external environmental influences such as voltage fluctuations, noise, and harmonics. It is vulnerable to waveform distortion, etc., and causes a problem that an error of a pulse generating point exceeds an allowable value.

An object of the present invention is to configure the entire circuit for the calculation of the SCR block opening point of the power supply device and the generation of pulses at the opening point with a digital circuit, thereby minimizing external environmental influences, thereby providing high-precision and accurate power control for a long time. It is possible to implement a digital power control device capable of enabling the safety of the operator.

According to an aspect of the present invention, there is provided a digital power supply control apparatus including: an SCR block configured to open and close by a pulse to rectify an AC power source, and including at least one SCR; A measurement block for measuring a power state of a load to which an output of the SCR block is applied; Phase calculating means for receiving a load power measurement value fed back from the measuring block and calculating a phase at which the SCR is opened to make the power state of the load uniform; Clock pulse counting means initialized by a zero crossing point of an input commercial power supply and counting clock pulses of a system clock; A digital comparator for comparing a clock pulse count input from said clock pulse counting means with a phase value input from said phase calculating means and generating a pulse generation signal for opening said SCR when it corresponds to each other; And pulse generation means for generating a pulse for opening the SCR according to the signal generated by the digital comparator.

According to an aspect of the present invention, there is provided a digital power supply control apparatus including: an SCR block configured to open and close by a pulse to rectify an AC power source, and including at least one SCR; A measurement block for measuring a power state of a load to which an output of the SCR block is applied; Clock pulse counting means initialized by a zero crossing point of an input commercial power supply and counting clock pulses of a system clock; Phase calculating means for receiving a load power measurement value fed back from the measuring block and calculating a phase in which the SCR is opened to make the power state of the load uniform, and converting it into a clock pulse count; A digital comparator for comparing the clock pulse count input from the clock pulse counting means with the clock pulse count input from the phase calculating means and generating a pulse generation signal for opening the SCR when the clock pulse count is matched; And pulse generation means for generating a pulse for opening the SCR according to the signal generated by the digital comparator.

The measuring block includes a digital multimeter for measuring the voltage and current of the load; And a digital filter for filtering the measured value of the digital multimeter.

The digital filter is characterized by selecting a middle rank among at least three consecutive measured values of the digital multimeter and inputting it to the phase calculating means.

The SCR block is characterized in that two SCRs are installed in opposite directions so that one side is opened with respect to the (+) portion of the AC commercial power and the other side is opened with respect to the (-) portion of the AC commercial power.

According to the present invention, by digitizing the configuration of the block for converting the AC commercial power to the DC power by the above configuration, it becomes possible to supply stable power while minimizing the influence on the external environment.

In particular, since it is possible to calculate the exact phase for opening / closing control of the SCR and to generate the pulse for the opening of the SCR at the correct time during the feedback control of the load power, it is possible to provide a stable power supply by minimizing the power control error. It is possible to keep the state of power supply constant by the change of external environment.

In addition, since the entire circuit is composed of digital circuits, unlike the existing analog devices, there is no need for zero adjustment of the variable resistor, thus saving time and effort due to zero adjustment in the existing industrial high voltage power supply, The worker's exposure can be cut off in advance, and the worker's safety can be achieved.

1 is a schematic diagram illustrating a configuration of a conventional power supply control device.
Figure 2 is a schematic diagram illustrating an SCR opening and closing process by a conventional power control device.
3 is a schematic diagram illustrating a configuration of main parts of a digital power supply control device according to an embodiment of the present invention.
Figure 4 is a schematic diagram illustrating an SCR opening and closing process by the digital power supply control apparatus of the embodiment of the present invention.
Figure 5 is a schematic diagram illustrating a comparison of the power control state by the digital power control device according to an embodiment of the present invention with the conventional one.
Figure 6 is a schematic diagram illustrating a comparison of the power control state by the digital power control device of the embodiment of the present invention with the conventional one.

Hereinafter, a configuration of a preferred embodiment of a digital power supply control apparatus according to the present invention having the above configuration will be described in detail with reference to the accompanying drawings.

3, the digital power supply control apparatus according to the embodiment of the present invention, the SCR block 120 for generating a DC power by rectifying the AC commercial power, and the feedback input of the measured value of the load for the generated DC power A measurement block 110, a phase calculation means 121 for calculating a phase for opening and closing the SCR block 120, a clock pulse counting means 123 for counting clock pulses of a system clock, and a clock pulse count In response to the result calculated by the phase calculating means 121, a digital comparator 125 for generating a pulse generation signal and a pulse for opening the SCR block 120 according to the pulse generation signal of the digital comparator 125. And pulse generating means 128 for generating.

The digital power supply control apparatus of this embodiment is for supplying power to the heater 200 used in the process of producing sapphire ingot by converting industrial AC commercial power (380V AC) into DC power, but not limited thereto. It can be applied to various devices requiring supply of

In the SCR block 120 of the present embodiment, when two SCRs are installed in opposite directions and one is positive of AC commercial power, a pulse of a constant amplitude is applied to the gate of the SCR, and the other is negative (-). At this time, a pulse of a predetermined amplitude is applied to the gate of the SCR to be opened. The opening point of the SCR is changed instantaneously according to the calculation result performed by comparing the load power measurement value of the measurement block 110 with a standard value.

The measurement block 110 of the present embodiment includes a digital multimeter 112 for measuring the voltage and current of the digital voltage controller load 111 and a digital filter 115 for filtering the measured values of the digital multimeter 112. It includes.

In the present embodiment, the digital multimeter 112 measures the voltage and current of the load 111 about three times per second, but is not limited thereto. In accordance with the performance or measurement speed of the digital multimeter 112, and , Depending on the stability level of the load 111 power required.

As shown in FIGS. 5 and 6, in the present embodiment, the digital filter 115 may cause variations in the load voltage, such as a case in which the power state of the load 111 has an instantaneous power fluctuation due to noise or opening and closing of a peripheral electric device. If present, these effects are eliminated or minimized.

For example, in the case of the conventional analog filter, since the measured value is immediately reflected and applied to the next commercial power input wave, even if the voltage value rises momentarily due to the influence of noise, the current state of the commercial power may be rather low. The fluctuation range of the voltage becomes large, and it may take a considerable time to control the state of the power supply. However, in the present embodiment, such a noise component is removed to improve the stability of the generated voltage and to quickly respond to the noise. Therefore, as shown in Figs. 5 and 6, the voltage fluctuation range and the fluctuation time of the present embodiment can be controlled to be minimum.

The digital filter 115 of the present embodiment is based on a ranking (Ranking) to rank the plurality of measurements of the digital multimeter 112, and select the value of the middle rank as the measurement value (Ranking), but it is not limited thereto. The multiple measurements of the multimeter 112 may be averaged or by a low pass filter (LPF), and various digital filtering methods may be used.

In the present embodiment, the rank is given to approximately 10 measured values, and the voltage and current values of the intermediate rank are taken and input to the phase calculating means 121, but it can be changed according to the embodiment.

For example, it is also possible to select 10 measurement values before and after each measurement value, select a medium rank, and input the same to the phase calculation means 121, and select only one measurement value for every 10 measurement values and calculate the phase calculation means 121. It is also possible to input the number, the number of measurements and the method of selecting the ranking can be changed, and the method of filtering can be changed according to the required level of stability for the generated power source.

The phase calculation unit 121 according to the embodiment of the present invention performs an inverse estimation of the waveform of the input commercial power supply according to the power supply state of the load 111 input from the digital filter 115, and an SCR block for controlling the state of the voltage ( 120) The opening point (phase) is detected.

For example, the AC commercial power has zero crossings at intervals of 180 °, and opening points are determined for each of the before and after points of the zero intersection, and the power is turned off every zero intersection.

For example, as shown in FIG. 5, the AC commercial power has a voltage difference depending on the supply time, and is approximately 360V during the day and approximately 390V at night, and the voltage difference between the night and the day reaches 30V. It may also occur due to seasonal or climatic influences or fluctuations of a device operating among a plurality of workplace power supplies as shown in FIG. 6.

In the production process of the sapphire ingot to which the digital power control device of the present embodiment is applied, the fluctuation of the voltage must be at the level of 7 mV, and if the state of the power supply beyond this exceeds 20 seconds, the production of the ingot has a fatal effect.

Therefore, the phase calculating means 121 of the present embodiment shifts the phase of the opening point backward when the load 111 voltage input value from the digital filter 115 is excessive, and the phase of the opening point forward when the voltage is too low. As controlled to move, the open phase value is determined by correlation with the waveform of the estimated commercial power supply (ie, amplitude or voltage).

In the present embodiment, the phase value, which is a calculation result for the opening point, may be directly input to the digital comparator 125 and compared with the corresponding clock pulse count, and the result value of the phase calculation unit 121 is itself a clock pulse count value. It is also possible to convert and give it to the digital comparator 125.

That is, as shown in FIG. 4, when the period of the AC commercial power is T and the system clock is t, when the pulse count corresponding to the half cycle (π) of the commercial power is N, N = T / (2t).

Then, when the phase of the SCR gate opening la Φ ₁ when (+) of the AC commercial power supply, the clock pulse count for a phase Φ ₁ is n is _1,

n ₁ = (NΦ ₁ ) / (π) = (Φ ₁ T) / (2πt)

Lt;

Of the AC commercial power supply (-), the clock pulse count for n ₂ the phase of the SCR gate to be opened when the phase Φ ₂ Φ ₂ is referred to,

n ₂ = (NΦ ₂ ) / (π) = (Φ ₂ T) / (2πt)

In the present embodiment, the clock pulse counting means 123 is initialized every zero intersections, and the clock pulse counts count clock pulses for the portions of the AC commercial power (+) and the portions of the (-), respectively.

The digital power supply control apparatus of this embodiment includes a phase detecting means 127 for detecting the phase of the AC commercial power, and the phase detecting means 127 detects the zero intersection point of the AC commercial power to the clock pulse counting means 123. In operation, the clock pulse counting means 123 initializes the clock pulse count every zero intersection.

In addition, the pulse count between the zero intersections makes it possible to control feedback on the frequency fine change of the AC commercial power by the phase calculating means 121.

The digital comparator 125 of the present embodiment receives the calculation result phase value of the phase calculating means 121, compares the clock pulse count of the clock pulse counting means 123, and detects a corresponding time point to generate the pulse generating means 128. Sends a pulse generation signal for opening the SCR block 120.

In the embodiment of the present invention, N is set sufficiently large, for example, the clock pulse count is set to be in the range of 10,000 to 30,000 for 1/2 cycle, so that the clock pulse count (integer) corresponding to the phase value in the corresponding range is set. ), The clock pulse count may vary depending on the required level of system or power stability, and is not limited to the above embodiment.

The pulse generating means 128 of the present embodiment inputs a pulse having a predetermined amplitude to the gate of the corresponding SCR according to the signal of the digital comparator 125 to open the SCR, and the portion of the AC commercial power supply (+) and (-) The outputs for the phosphorus portions are combined and input into the load as DC current.

In addition, in the measurement block 110, there is a state measurement of the power supply of the load 111 by the digital multimeter 112 and measurement measurement filtering by the digital filter 115, and accordingly, feedback control by the phase calculation unit 121 is performed. Becomes possible.

It is obvious that the scope of the present invention is not limited to the above embodiments but is defined by the matters defined in the claims of the present invention and includes various modifications and alterations made by those skilled in the art within the scope of the claims.

110 ...... Measure block 111 ...... Load
112 ...... Digital Multimeter 115 ...... Digital Filter
120 ...... SCR block 121 ...... Phase calculation means
123 ...... clock pulse count means 125 ...... digital comparator
127 ...... Phase detection means 128 ...... Pulse generation means

Claims (5)

An SCR block that is opened and closed by a pulse to rectify an AC power source, and includes at least one SCR;
A measurement block for measuring a power state of a load to which an output of the SCR block is applied;
Phase calculating means for receiving a load power measurement value fed back from the measuring block and calculating a phase at which the SCR is opened to make the power state of the load uniform;
Clock pulse counting means initialized by a zero crossing point of an input commercial power supply and counting clock pulses of a system clock;
A digital comparator for comparing a clock pulse count input from said clock pulse counting means with a phase value input from said phase calculating means and generating a pulse generation signal for opening said SCR when it corresponds to each other;
And pulse generation means for generating a pulse for opening the SCR according to the signal generated by the digital comparator.
An SCR block that is opened and closed by a pulse to rectify an AC power source, and includes at least one SCR;
A measurement block for measuring a power state of a load to which an output of the SCR block is applied;
Clock pulse counting means initialized by a zero crossing point of an input commercial power supply and counting clock pulses of a system clock;
Phase calculating means for receiving a load power measurement value fed back from the measuring block and calculating a phase in which the SCR is opened to make the power state of the load uniform, and converting it into a clock pulse count;
A digital comparator for comparing the clock pulse count input from the clock pulse counting means with the clock pulse count input from the phase calculating means and generating a pulse generation signal for opening the SCR when the clock pulse count is matched;
And pulse generation means for generating a pulse for opening the SCR according to the signal generated by the digital comparator.
The apparatus of claim 1 or 2, wherein the measurement block comprises: a digital multimeter for measuring voltage and current of the load;
And a digital filter for filtering the measured value of the digital multimeter.
The method of claim 3, wherein the digital filter,
And selecting a middle one of the at least three consecutive measured values of the digital multimeter and inputting the same to the phase calculating means.
The method according to claim 1 or 2, wherein the SCR block is characterized in that the two SCRs are installed in opposite directions to each other, one side is opened with respect to the (+) part of the AC commercial power supply, the other side with respect to the (-) part of the AC commercial power source. Digital power control device.

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