KR200294759Y1 - An unitive switch type complex electronic Watt-hour meter - Google Patents

Abstract

Receives a power circuit unit for rectifying the input AC power and supplying it to the operating power, a power amount detector for converting the supplied power into voltage and current, and amplifying and outputting a signal proportional to the power used, and an output signal of the power amount detector. A control unit composed of a plurality of auxiliary devices including a central processing unit (CPU) that performs a function of integrating power consumption and outputs a signal for controlling an external device, and switches the general load and the late night load by a control signal of the control unit. A switch-mounted integrated electronic wattmeter having a power switch and a display unit for displaying a content to be displayed to a user by a signal provided from a control unit, wherein the switch unit integrally measures the use of a general load and a midnight load. Voltage divided by input voltage and converted into several volts Circuit; General-purpose current transformer for converting the general-purpose power supplied from the power company into a current to provide to the rear end; A midnight current transformer for converting the late night power supplied from the electric power company into a current and providing the rear end; Switch integrated integrated electronic wattmeter characterized in that it comprises a signal amplifier for amplifying and outputting a small signal current of a predetermined level or less of the signals provided from the general-purpose / midnight current transformer.

Description

Switchgear integrated electronic watt-hour meter {An unitive switch type complex electronic Watt-hour meter}

The present invention relates to a switch-integrated composite electronic watt-hour meter that can measure general load and midnight load at the same time, and more particularly, to a switch-integrated composite electronic wattmeter that can perform accurate metering by amplifying even a minute analog signal.

Until now, mechanical watt-hour meters have been mainly used to measure the amount of electric energy used in the home. Since the mechanical wattmeter uses a mechanical number of rotation as an indicator, even if there is a power failure during use, the numeric display shows the value measured so far so that the measured value could be confirmed.

However, in recent years, as the power generation of the industry and electricity consumption increase, the effective power amount (kWh), the reactive power amount (kVARh), the power factor, and the time of use metering of the general load and the late night load There is also a demand for electronic meters with multi-functions, such as remote meter reading systems.

Among them, a customer who uses both a normal load and a midnight load at the same time needs a general electricity meter and a midnight electricity meter to measure the amount of power used by the load, and a time for supplying the midnight power to an arbitrary start time and end time. Various techniques have been proposed to solve the problem of the complexity of the system for the connection of the power supply and the general-purpose / midnight load due to the configuration of the switch.

Among them, description will be made based on Patent No. 309621 (Application No. 1998-0028985) as follows. 1 is a block diagram of an electronic power meter control circuit according to Patent No. 305961. Referring to FIG. 1, the electronic electricity meter is largely comprised of a power supply circuit unit 40, a general power / frequency conversion unit 50, a midnight power / frequency conversion unit 60, a digital circuit unit 70, and a display unit ( 80) and a late night power supply opening and closing portion 90.

To describe each control circuit in detail, first, the power circuit unit 40 is composed of a power transformer 41, a power circuit 42, the power failure compensation unit 43, the primary side of the power transformer 41 is connected to the power supply side. The output is used in series with the power supply circuit 42. The output of the power supply circuit 42 is supplied to the operating power of each circuit section. The power failure compensator 43 is an auxiliary operation power supply circuit which is supplied to maintain various data of the meter and the electronic clock at the time of power failure.

In addition, the general-purpose power / frequency converter 50 is composed of a potential transformer (51), a current transformer (52), a multiplier (53), and a frequency converter (54). Instrument transformer 51 is connected in parallel with the power supply side (1S, 2S) receives an input, the current transformer 52 receives an input connected in series with the power supply side (2S). The voltage signal and the current signal output from the instrument transformer 51 and the current transformer 52 are applied to the input of the multiplier 53. The multiplier multiplies the current and voltage and then supplies its output to frequency converter 54. The frequency converter 54 inputs a frequency proportional to the electric power to the CPU 71 of the digital circuit unit 70.

Here, the late night power / frequency converter 60 is also constituted by a device of the same method as the general power / frequency converter 50. That is, it consists of a general-purpose power / frequency conversion unit 50 and a late-night power / frequency conversion unit 60 has two meter functions inside one electronic wattmeter.

The digital circuit unit 70 includes a CPU 71, a real time clock (RTC) 72, a crystal oscillator 73, an EEPROM 74, a RAM / ROM 75, a battery monitoring unit 76, an operation switch ( 77). The frequencies output from the frequency converters 54 and 64 of the general purpose and late night power / frequency converters 50 and 60 are applied to the CPU 71. RTC (72) is a part that creates the clock function required in the meter, the measurement data of 1 second unit is input to the CPU, the crystal oscillator 73 is used as the oscillator necessary for the operation of the CPU 71, the crystal oscillator of the CPU It is input to the connection terminal of 73. The EEPROM 74 is used as a nonvolatile memory for storing weighing data calculated and calculated by the CPU, and the ROM / RAM 75 is used as a place for storing a program for the CPU to operate. The battery monitoring unit 76 is a circuit for detecting battery low voltage and is connected to an input port of the CPU 71. The CPU 71 outputs the weighing data to the LCD 81 so that the contents of the weighing data can be shown to the user. The display unit 80 is configured of an LCD 81 so that the CPU 71 can display contents to be displayed to the user. The input signal of the LCD 81 is output from the CPU 71.

On the other hand, the late-night power supply opening and closing portion 90 is composed of a switch 91. A switch ON / OFF operation is performed by inputting an open / close signal output from the CPU 71 of the digital circuit unit 70 to the switch 91. The power source to be opened and closed connects (1S) and (2S) to (3L) and (4L), respectively, in the middle of which the power is cut off and the opening / closing operation of the connection is performed.

The operation of the conventional electronic wattmeter configured as described above will be described.

The power supply circuit unit 40 receives AC power from the power supply side and converts the AC power into DC required by various circuit units inside the electronic wattmeter. The power supply 41 converts AC power to the power supply circuit 42. Voltage down to a predetermined value that can be rectified in The control circuit is operated by receiving the lowered predetermined driving voltage, and the general power / frequency converting unit 50 uses the power supplied from the power supply company using the instrument transformer 51 and the current transformer 52. After converting the voltage into a voltage of several volts, the multiplier 43 multiplies the multiplier 43 to the frequency converter 54. The frequency converter 54 converts a signal proportional to the power used in the load into a frequency to convert the digital circuit unit 70 into a frequency. Is applied to the CPU 71. On the other hand, the midnight power / frequency converter 60 performs the same operation as the general-purpose power / frequency converter 50 described above.

On the other hand, the CPU 71 of the digital circuit unit 70 divides the frequency signals output from the general frequency converter 54 and the night frequency converter 64 in a constant manner to determine the amount of power (kWh) used in the general / night load. Calculate and weigh each separately. Thereafter, the amount of power used for general use / night use is recorded in the EEPROM 74 so that the measured data can be maintained even in the case of power failure.

The instrument has a battery monitoring unit 76 which always monitors the remaining battery during normal operation. When the remaining battery voltage falls below a certain level, the battery 71 is notified to the battery low voltage signal (Battery Low Voltage). The CPU 71 displays the battery low voltage error on the LCD 81 of the display unit 80. The RTC 72 serves to provide accurate current time information to the CPU 71, and the CPU 71 continuously monitors the current time to generate a precise cut-off and connection signal at night power off time or night power supply time. To operate the switch 91 of the late-night power supply opening and closing portion 90. The operation switch 77 is used as a means for freely setting and inputting a late night start time and end time. The late-night power switch 90 is a part that connects and cuts off the power supplied from the power supply company to the late-night load. The power switch 91 according to the open / close signal output from the CPU 71 of the digital circuit unit 70. To perform the on / off operation. The display unit 80 includes an LCD 81, and the displayed contents are error items such as the current monthly / monthly general load power usage, the current monthly / monthly midnight load power usage, and the battery low voltage error.

This conventional electronic watt-hour meter is heavy by using the general purpose / midnight transformers 51 and 61, multipliers 53 and 63 for power integration, and two frequency converters 54 and 64, and its structure. Is complicated and the accuracy of the measured values is also relatively poor.

The object of the present invention is to provide an electronic meter with accurate measured values.

Another object of the present invention is to reduce the volume of the product by simplifying the circuit of the electronic meter.

Another object of the present invention is to reduce the manufacturing cost of an electronic electricity meter by processing some functions using software.

The electronic watt-hour meter according to the present invention for achieving the above objects is a power circuit unit for rectifying the input AC power supply to the operating power supply, and converts the supplied power into voltage and current and amplifies and outputs a signal proportional to the power used Operation of the central processing unit (CPU) including a power amount detecting unit and a central processing unit (CPU) for receiving an output signal of the power amount detecting unit and integrating the amount of used power and outputting a signal for controlling an external device. A control unit including a plurality of auxiliary devices to assist the control unit, a power switch for switching the general load and the late-night load according to the control signal of the control unit, and a display unit for displaying contents to be displayed to the user by a signal provided from the control unit. Integrated electronic switchgear for weighing both general and midnight loads In ryeokryang system, wherein the power amount detector: a voltage divider circuit to provide at the rear end to be converted to a bolt (Volt) to the voltage divider input to the power supply circuit; General-purpose current transformer for converting the general-purpose power supplied from the power company into a current to provide to the rear end; A midnight current transformer for converting the late night power supplied from the electric power company into a current and providing the rear end; Characterized in that it comprises a signal amplifier for amplifying and outputting a small signal current of a predetermined level or less of the signal provided from the general-purpose / midnight current transformer.

A detailed feature of the electronic power meter according to the present invention is that the central processing unit (CPU) of the control unit converts the analog signal provided through the voltage divider circuit and the analog signal provided through the signal amplifier of the power amount detection unit into a digital signal. An A / D converter; A volatile memory (RAM) and a nonvolatile memory (ROM) used as a storage device for data processing; It is a built-in memory device that stores software that can implement the clock function.

1 is a block diagram showing a switch-integrated composite electric power meter according to the prior art,

2 is a block diagram showing a switch-integrated composite electric power meter according to the present invention.

Hereinafter, an electronic wattmeter according to the present invention will be described with reference to the accompanying drawings. 2 is a block diagram showing a switch-integrated composite electric power meter according to the present invention.

Looking at the configuration, the power supply circuit unit 240, the power amount detection unit 250 for detecting the voltage and current supplied to each circuit unit via the power supply circuit unit 240, and the output signal of the power amount detection unit 250 input A control unit 270 that integrates the amount of power used to control the external device, a power switch 290 that switches the general load and the late-night load by the control signal of the controller 270, and the controller 270 And a display unit 280 for displaying contents to be displayed to the user by a signal.

Since the power circuit unit 240, the display unit 280, and the switch 290 have the same configuration as the electronic electricity meter according to the related art shown in FIG. 1, the same operation may be performed. Therefore, detailed description thereof will be omitted to avoid unnecessary duplication. However, unlike the prior art, it can be seen that the present invention provides a voltage from the power supply transformer 241 of the power supply circuit unit 240 to the voltage divider circuit 251.

The power amount detector 250 divides the voltage input to the power transformer 241 of the power circuit unit 240, converts the voltage into several volts, and provides the voltage divider circuit 241 to be provided at a later stage, and is supplied from a power company. General-purpose current transformer 252 for converting the general-purpose power to the current to provide the rear end, the late-night current transformer (253) for converting the late-night power supplied from the power company to the current to provide the rear-end, and general / midnight current transformer (252) And a signal amplifier 254 for amplifying a small signal current below a predetermined level among the signals provided from the signal 253.

The control unit 270 includes a central processing unit (CPU) 271, a crystal 272, an EEPROM 273, a battery detecting unit 274, and an operation switch as an auxiliary device required for the operation of the central processing unit 271. (275) and the like. Unlike the related art, the CPU 271 converts an analog type voltage signal provided through the voltage divider circuit 251 and an analog signal provided through a signal amplifier of the power amount detector into a digital signal. An A / D converter; A volatile memory (RAM) and a nonvolatile memory (ROM) used as a storage device for data processing; It has a built-in storage device that stores software that can implement the clock function. Unlike the prior art, a clock function program is created and processed in software without using an external real time clock (RTC), which simplifies the circuit and reduces production costs.

In the prior art, the general-purpose transformer 51 and the late-night transformer 61 are used, and the weight of the wattmeter is heavy. In the present invention, the voltage divider circuit 251 is converted into a constant voltage and then transferred to the A / D converter inside the CPU 271, thereby simplifying the circuit and reducing the volume.

The values converted into current signals by the general current transformer 252 and the late-night current transformer 253 are transmitted to the signal amplifier 254, respectively. Values above a certain level among the signals transmitted to the amplifier 253 are passed through to the A / D converter in the CPU 271 in the subsequent stage. However, a signal that does not reach a predetermined magnitude, that is, a small signal, is amplified by the signal amplifier 254 and applied to the CPU 271 of the central processing unit 270. By amplifying the micro signal in this way, accurate weighing is achieved by accurately measuring an analog signal of a very small magnitude.

The A / D converter 271 in the central processing unit 270 converts the transmitted analog signal into a digital signal. The voltage signal provided through the power voltage dividing circuit 251 and the DC signal of a predetermined magnitude or more that are amplified or passed through the signal amplifier 254 are the targets.

In the prior art, multipliers 53 and 63 are used to multiply the values provided from the transformers 51 and 61 and the current transformers 52 and 62, and the pulse width modulated signals pulse using the frequency converters 54 and 64. width modulation signal) was converted into a frequency and applied to the CPU 271. In the present invention, the A / D converter inside the central processing unit 271 is integrated without using a frequency converter, and power consumption is accumulated, and the complexity of the circuit is reduced by loading the CPU inside the CPU without using an external ROM / RAM. It became possible.

Although the above description has been given of the preferred embodiments of the present invention, the present invention is not limited thereto, and it is possible to carry out various modifications within the scope of the utility model registration and the detailed description of the invention and the scope of the accompanying drawings. It is natural to fall within the scope of the invention.

As described above, the complex electronic power meter according to the present invention can accurately measure a very small analog signal by amplifying a small signal using an amplifier, thereby enabling more accurate metering. The circuit complexity is reduced by using the internal ROM / RAM in the CPU instead of using an external ROM / RAM, and the cost is reduced by reducing the size of the product by simplifying the entire circuit. It also saves parts costs by creating and processing a clock program in software without using an external RTC.

Claims (2)

Inputs a power circuit unit for rectifying the AC power input to supply the operating power, a power amount detector for converting the supplied power into voltage and current, and amplifies and outputs a signal proportional to the power used, and the output signal of the power amount detector A control unit including a central processing unit (CPU) for performing a function of accumulating the amount of used power and outputting a signal for controlling an external device, and a plurality of auxiliary devices to assist the operation of the central processing unit (CPU); A power switch for switching the normal load and the late night load by the control signal of the control unit and a display unit for displaying the content to be displayed to the user by the signal provided from the control unit to measure the use of the general load and the late night load at the same time In the switch-integrated composite electronic wattmeter, the power amount detection unit: A voltage divider circuit for dividing the voltage input to the power supply circuit unit, converting the voltage into several volts, and providing the voltage to a rear end thereof; General-purpose current transformer for converting the general-purpose power supplied from the power company into a current to provide to the rear end; A midnight current transformer for converting the late night power supplied from the electric power company into a current and providing the rear end; Switch integrated integrated electronic wattmeter characterized in that it comprises a signal amplifier for amplifying and outputting a small signal current of a predetermined level or less of the signals provided from the general-purpose / midnight current transformer. The CPU of claim 1, wherein the CPU of the controller comprises: An A / D converter for converting an analog signal provided through the voltage dividing circuit and an analog signal provided through a signal amplifier of the power amount detection unit into a digital signal; A volatile memory (RAM) and a nonvolatile memory (ROM) used as a storage device for data processing; Switchgear integrated electronic electricity meter, characterized in that the built-in storage device that stores software that can implement the clock (clock) function.