JP6040679B2 - Power supply device and current measuring device having the same - Google Patents

Description

  The present invention relates to a power supply device that generates power from a single-phase three-wire voltage line, and a current measurement device including the power supply device.

  In recent years, there is concern about the depletion of global resources necessary for people to live, and there is an urgent need to deal with environmental problems such as global warming due to the influence of carbon dioxide generated by the consumption of resources. Responding to power shortages associated with the shutdown of nuclear power plants and the increase in electricity charges associated with gradually increasing the ratio of natural energy such as solar power and wind power generation by gradually reducing the ratio of nuclear power generation Is also in a hurry. For this reason, even in ordinary households, energy saving orientation such as replacement with low power consumption devices has progressed, and interest in reducing electricity charges has also increased.

  In such a situation, as a system for monitoring and displaying power consumption, a current transformer is attached to a single-phase three-wire voltage line arranged in the distribution board, and the detection signal is a current measurement function. In addition, there is provided a system that inputs a distribution board measuring instrument having a wireless communication function and transmits a current measurement value to a management server on the Internet via a wireless LAN base unit and a router (Non-Patent Document 1).

  However, since the distribution board measuring instrument in this system uses a battery as a power source, it takes time to replace the battery if the battery runs out. Although power can be supplied from the power adapter, a power adapter and a power outlet are required. Moreover, although it is known that the power supply power of the current measurement circuit is obtained using the induced voltage from the current transformer (Non-patent Document 2), the induced voltage cannot be obtained when no current flows through the measurement target.

[Search September 27, 2012], Internet <http://flets.com/eco/miruene/service.html> [Search September 27, 2012], Internet <http://www.toyodenki.co.jp/html/it_turtle.html>

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a current provided with a current measurement circuit for measuring a current flowing in a current transformer attached to a single-phase three-wire voltage line. It is to be able to generate the power of the measuring device without using the induced voltage from the battery, the power adapter, and the current transformer.

Power supply device according to the present invention includes two current transformer attached to the two voltage lines of the single-phase three-wire system, and a rectifying and smoothing circuit connected between the two current transformers, the 2 Current flowing through a loop formed by two voltage lines, two coupling capacitors formed between the two voltage lines and the two current transformers, the two current transformers, and the rectifying and smoothing circuit. the charge accumulated in the smoothing capacitor constituting the rectifying and smoothing circuit, the charge as a source power, a power supply device for supplying a current measuring circuit which is a load to measure the current flowing through the two current transformer.
Current measuring device according to the present invention includes a power supply device according to the present invention, a current measuring device and a said current measuring circuit.

[Action]
According to the present invention, two voltage lines of a single-phase three-wire system, a current transformer attached to each voltage line, a coupling capacitor formed between each voltage line and a current transformer attached to each voltage line, and rectification and the charge current flowing through the loop formed by the smoothing circuit is stored in the smoothing capacitor constituting the rectifying and smoothing circuit is supplied to the current measuring circuit which is a load to the charge as the source power.

  According to the present invention, power from a battery, a power adapter, and a current transformer is supplied from a current measuring device including a current measuring circuit that measures a current flowing through a current transformer attached to a single-phase three-wire voltage line. It can be generated without using an induced voltage.

It is a figure for demonstrating the circuit structure of the power supply device of the electric current measurement apparatus which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating operation | movement when the voltage of a predetermined | prescribed polarity is input into the voltage line in the power supply device of the electric current measurement apparatus which concerns on the 1st Embodiment of this invention. FIG. 3 is a diagram for explaining an operation when a voltage having a polarity opposite to that of FIG. 2 is input to a voltage line in the power supply device for the current measuring device according to the first embodiment of the present invention. It is a figure for demonstrating the circuit structure of the power supply device of the current measurement apparatus which concerns on the 2nd Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
[First embodiment]
FIG. 1 is a diagram for explaining a circuit configuration of a power supply device for a current measuring instrument according to a first embodiment of the present invention.

  In the figure, a neutral line 1, a first voltage line 2, and a second voltage line 3 are provided between a main switch and a branch switch arranged inside a distribution board (not shown). This is a single-phase three-wire distribution line. That is, the neutral line 1 is grounded, and the first voltage line 2 and the second voltage line 3 are supplied with an AC voltage of 100 V of opposite polarity.

  A first current transformer 4 is attached to the outer periphery of the first voltage line 2, and a first current measuring circuit 6 is connected to both ends of the winding L1. A second current transformer 5 is attached to the outer periphery of the second voltage line 3, and a second current measuring circuit 7 is connected to both ends of the winding L2.

  A coupling capacitor C1 is formed between the first voltage line 2 and the first current transformer 4, and a coupling capacitor C2 is formed between the second voltage line 3 and the second current transformer 5. . It is preferable to positively increase the coupling capacitance by disposing metal electrodes on the inner peripheral surface of each current transformer. Further, the coupling capacitance can be increased by reducing the inner diameter of each current transformer or increasing the length thereof.

  The first and second current transformers 4 and 5 are current sensors called through-type current transformers (hollow coils in which electric wires are wound around a ferromagnetic core material), and are first conductors that pass through. , A current proportional to the current flowing through the second voltage lines 2 and 3 flows through the windings L1 and L2, so that the current flowing through the first and second voltage lines 2 and 3 can be detected.

  The first and second current measurement circuits 6 and 7 include, for example, a current / voltage conversion circuit, an A / D conversion circuit, and the like. The currents detected by the first and second current transformers 4 and 5 are Digitize proportional voltage.

  A rectification and smoothing circuit 8 is connected between the winding L1 of the first current transformer 4 and the winding L2 of the second current transformer 5 via lines L3 and L4. A load 9 is connected to the output side of 8.

  The load 9 is a wireless communication circuit that transmits the measurement values of the first and second current measurement circuits 6 and 7 to the wireless master unit via a wireless LAN, a control device that controls the entire current measurement device, and the like. For the sake of convenience, although shown separately from the load 9, the first and second current measurement circuits 6 and 7 also constitute the load 9.

  The rectifying and smoothing circuit 8 is composed of a double wave (full wave) rectifying circuit composed of a diode bridge composed of four diodes D1 to D4 and a smoothing circuit composed of an electrolytic capacitor C3 connected to the output side thereof. Then, electric power using the electric charge accumulated in the electrolytic capacitor C3 as a power source is supplied to the load 9.

  Next, the operation when the output of the rectification and smoothing circuit 8 is supplied to the load 9 will be described. FIG. 2 shows an operation when a positive voltage is applied to the first voltage line 2 and a negative voltage is applied to the second voltage line 3, and FIG. 3 shows a positive voltage applied to the second voltage line 3 and the first voltage line. 2 shows the operation when a negative voltage is applied. In these drawings, the alternate long and short dash line indicates a current path.

  As indicated by the one-dot chain line in FIG. 2, when a positive voltage is applied to the first voltage line 2 and a negative voltage is applied to the second voltage line 3, “first voltage line 2 → coupling capacitance C 1 → winding”. A current flows through a loop composed of a line L1, a line L3, a diode D1, an electrolytic capacitor C3, a load 9, a diode D4, a line L4, a winding L2, a coupling capacitor C2, and a second voltage line 3.

  Further, as indicated by a one-dot chain line in FIG. 3, when a positive voltage is applied to the second voltage line 3 and a negative voltage is applied to the first voltage line 2, the expression “second voltage line 3 → coupling capacitance C2” is applied. The current flows through a loop formed by “winding L2 → line L4 → diode D2 → electrolytic capacitor C3 → load 9 → diode D3 → line L3 → winding L1 → coupling capacitance C1 → first voltage line 2”.

[Second Embodiment]
FIG. 4 is a diagram for explaining a circuit configuration of a power supply device for a current measuring instrument according to the second embodiment of the present invention. Here, only the parts different from the first embodiment are shown.

  In the present embodiment, a switch 10 and a timer as means for generating a control signal for controlling on / off (open / close) of the switch 10 between the rectifying and smoothing circuit 8 and the load 9 in the first embodiment or A voltage measurement circuit 11 is provided, and the switch 10 is switched from OFF (open) to ON (closed) when a predetermined amount of electric charge is accumulated in the electrolytic capacitor C3 of the rectifying and smoothing circuit 8, and the load 9 is driven. It is a thing.

  Here, the accumulation of the predetermined amount of charge means that the switch 10 has been in the OFF state for a predetermined time, or that the voltage across the electrolytic capacitor C3 is measured by the voltage measurement circuit. Detection can be based on the fact that the value has reached a predetermined value. The timer or voltage measurement circuit 11 constitutes a load 9.

[Example]
Next, examples will be described. Attach a current transformer to the two single-phase three-wire voltage lines between the main switch in the distribution board (called an ampere breaker or service breaker by the power company) and the branch switch. When the AC voltage between the windings of the two current transformers was measured, it was about 1.73V. Further, the current was rectified with a diode bridge and a 3.3 μF electrolytic capacitor between the windings of the two current transformers, and allowed to stand for 15 minutes. As a result, a DC voltage of 9 V or more was obtained. When a 1 MΩ resistor was connected in parallel with this electrolytic capacitor, a DC voltage of 112 mV was obtained.

  As described above in detail, according to the power supply device for the current measuring device according to the embodiment of the present invention, the first and second voltage lines 2 and 3 of the single-phase three-wire system, the coupling capacitors C1 and C2, the first Since the current flowing in the loop formed by the first and second current transformers 4 and 5 and the rectifying and smoothing circuit 8 is rectified and smoothed by the rectifying and smoothing circuit 8, the output power is used as the power supply power of the current measuring device. The power supply can be generated without using the induced voltage from the battery, the power adapter, and the first and second current transformers 4 and 5.

2 ... 1st voltage line, 3 ... 2nd voltage line, 4 ... 1st current transformer, 5 ... 2nd current transformer, 6 ... 1st current measurement circuit, 7 ... 2nd current measurement circuit, 8 ... Rectification and smoothing circuit, 9 ... Load, 10 ... Switch, 11 ... Timer or voltage measurement circuit.

Claims (4)

Two current transformers attached to two single-phase three-wire voltage lines;
A rectification and smoothing circuit connected between the two current transformers,
The two voltage lines, two coupling capacitors formed between the two voltage lines and the two current transformers, the two current transformers, and a loop formed by the rectifying and smoothing circuit are flowed. stores charge current to the smoothing capacitor constituting the rectifying and smoothing circuit, the charge as a source power, the power supply to supply to the current measuring circuit is a load to measure the current flowing through the two current transformer. The power supply device according to claim 1,
A power supply device in which a metal electrode is disposed on an inner peripheral surface of the current transformer. The power supply device according to claim 1,
A power supply apparatus in which a switch and a timer or a voltage measurement circuit for generating a control signal for controlling on / off of the switch are connected to an output side of the rectifying and smoothing circuit. A current measuring device comprising the power supply device according to claim 1 and the current measuring circuit.

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