JPH0923568A - Open-phase detector of power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-performance open-phase detector of a power supply which remarkably simplifies the hardware and dispenses with a gain adjustment. SOLUTION: The phase voltage or line voltage of a power supply is detected by a phase input detecting section 10 of a powder supply. The detected signal is counted by a counter 21 of a count processing section 20 to obtain a count signal. On the basis of the count signal and the detected signal, a calculating section 30 makes a calculation and then detects the open phase of the power supply.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an open-phase detecting device for a power supply, and more particularly to an open-phase detecting device effective for detecting open-phase of a power supply such as an inverter.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram of a conventional power supply phase loss detection apparatus. In FIG. 7, 1 is an analog differential amplification section, 2 is a full-wave rectification section, 3a and 3b are comparators, and 4 is a failure. It is a phase detection output unit.

In the phase loss detecting device of FIG. 7, the voltages of the respective phases of the input power supplies R, S and T are input to the differential amplifying section to generate R,
The phase voltage of S and T is detected, and this phase voltage is full-wave rectified.
The comparator section compares this full-wave rectified waveform with a reference voltage to detect the open phase state of the power supply.

[0004]

When the detection method shown in the prior art is used, since the configuration uses an analog operational amplifier, the hardware becomes complicated and the detection gain needs to be adjusted.

On the other hand, in elevator control, since it is necessary to detect a malfunction of a control relay or the like due to a phase loss of a power source, this phase loss detection is required, and the hardware configuration is complicated.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a high-performance open-phase detecting device for a power supply that simplifies hardware and does not require gain adjustment.

[0007]

In order to achieve the above-mentioned object, a phase failure detecting device for a power supply according to the present invention uses a phase input for inputting a voltage of each phase of the power supply and detecting a state of the voltage of each phase. A detection unit, a phase detection signal of the phase input detection unit as an input, a counting processing unit that performs a count process, a phase detection signal of the phase input detection unit and a count processing signal of the count processing unit as an input, and arithmetic processing is performed. And a signal state change detection unit that detects a change in a voltage detection signal between each phase of the power supply or between the phases and the signal change detection unit. A time recording unit that records the change time of the voltage detection signal by inputting the detection signal of the unit and the time signal of the internal timer, and an interrupt processing unit that performs interrupt processing by inputting the state change signal of the signal state change detection unit, and With the time signal of the time recording unit Open phase detection calculating unit for performing phase loss detection interrupt signal interrupt processing unit as an input, characterized by being constituted by.

The phase input detecting section includes a photocoupler for each phase including a light emitting diode connected to each phase of the power source input and a light receiving transistor for receiving light from the light emitting diode, and a reverse coupler for the light emitting diode of the photocoupler for each phase. A diode connected in parallel and a logic circuit that receives the output signal of the light receiving transistor as an input, the output side of the light emitting diode corresponding to each phase is commonly connected, and the phase voltage is applied by the logic circuit corresponding to each phase. Is provided with a phase voltage detecting means.

Means for detecting the open phase of the power source from the phase voltage signal of the phase input detection section and the count value of the counter, and the arithmetic processing section inputs the phase voltage signal of the phase input detection section. Is equipped with.

The counting processing section is composed of a logic circuit for performing a logic operation with each phase voltage signal of the phase input detection section as an input, and a counter for counting with a logic operation output signal of the logic circuit as an input.

The phase input detection section is composed of a line voltage detection section for detecting the line voltage of the power supply.

A resistor, a primary side diode of a photocoupler, and a diode connected in anti-parallel with this diode are connected from each phase of the power supply input to a common point to detect the phase voltage of the power supply, and the detected voltage is detected by the CPU. An input port connected to
The signal is input to the gate signal input terminal of the counter, and the phase failure of the power supply is detected from the state of the CPU input port and the count value of the counter.

A resistor, a primary side diode of a photocoupler, and a diode connected in antiparallel to this diode are connected from each phase of the power supply input to a common point to detect the phase voltage of the power supply, and the detected voltage is detected by the CPU. An input port connected to
The rising interval signal of this detection voltage is input to the circuit, and this rising interval signal is input to the gate signal input terminal of the counter to detect the open phase of the power supply from the state of the CPU input port and the count value of the counter. .

The line voltage of the power supply input is connected to the resistor, the primary side diode of the photocoupler, and the diode connected in antiparallel with this diode to detect the line voltage of the power supply, and this detected voltage is connected to the CPU. The input signal is input to the selected input port and the gate signal input terminal of the counter, and the phase failure of the power supply is detected from the state of the CPU input port and the count value of the counter.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

FIG. 4 is a block diagram of a power source open phase detecting device showing the principle of the present invention. In FIG. 4, 10 is a phase input detecting section for detecting the state of each phase of the power source, and 20 is a phase input detecting section. A counting processing unit for counting the phase detection signal of 10 as an input, 30 is an arithmetic processing unit (CPU), and the counting data from the counting processing unit 20 through the data bus 31 and the input line 32.
Through the phase detection signal from the phase input detection unit 10 to perform an arithmetic processing to output the open phase detection signal, and the control line 3
A control signal is input to the counting processing unit 20 through 3.

1 and 2 show a first embodiment of the present invention. FIG. 1 is a block diagram showing a specific configuration of the arithmetic processing section 30, and FIG. 2 is a specific example of the phase input detection section 10. It is a circuit diagram which shows an example. In FIG. 1, 31 is a signal state change detection unit for detecting rising / falling edges, 32 is an interrupt processing unit,
Reference numeral 33 is an internal timer, 34 is a time recording unit, and 35 is an open phase detection calculation unit. As shown in FIG. 2, the phase input detection unit 10
Is a photocoupler 17R including resistors 11 to 13, a diode 14, a light emitting diode 15 and a light receiving transistor 16.
(17S, 17T), resistor 18 and logic circuit 19
Composed of

Resistors 11 to 13, photocoupler 17R (17
(S, 17T) light-emitting diode 15 and a diode 14 connected in antiparallel to the light-emitting diode 15 in the photocoupler constitutes the primary side, and the secondary side is the light-receiving transistor 16 and resistor 18 of the photocoupler and the secondary side. A logic circuit 19 for detecting the on / off state of the light receiving transistor 16 is used.

By connecting in this way, a phase voltage is input from the respective phases of the power input R, S, T to the common connection point A, and the output is supplied for each half cycle of each phase of the R, S, T. A phase voltage detection waveform that turns on and off can be obtained. This phase voltage detection waveform is input to the gate input terminal of the counter 21 of the counting processor 20 and the input terminal of the CPU 30. Clock input is counted when the gate input terminal is high level "1".

When this detection circuit is used, it becomes possible to detect the time when the detection waveform of each phase is "1".
The state of each phase can be known from the level of the terminal input to U30.

As shown in FIG. 3, the phase detection voltage waveforms "1" and "0" are detected for each half cycle of each of the three phases of the input power supply, and the counter is detected only while these detection waveforms are "1". 21 counts, and the period of "1" of each phase can be known from this count value.

When the input power supply is out of phase and the input voltage is completely zero, a change occurs in the period of "1" of each phase, so that the count value changes and can be detected. Becomes In the arithmetic processing unit 30 of FIG. 1, the signal state change detection unit 31 for detecting the rising / falling edge of a signal receives the phase voltage detection signal as input and detects the rising / falling edge of the detection signal. The interrupt processing unit 32 is the signal state change detection unit 3
Interrupt processing of the state change signal 1 is performed. The time recording unit 34 records the time by inputting the state change detection signal of the signal state change detection unit and the clock signal of the internal timer 33. Open phase detection calculation unit 35
Detects an open phase by using the output signals of the interrupt processing unit 32 and the internal timer 34 as inputs.

According to the open phase detecting apparatus of the first embodiment, the phase voltage detection waveform is input to the high speed input terminal of the arithmetic unit 30. This terminal is connected to a timer inside the CPU and can record the rising and falling times of the level of each terminal. Therefore, it becomes possible to detect the time when the detected waveform of each phase is one, and also the state of each phase can be known from the level of each terminal.

When the input power supply is open-phase and the input voltage is completely zero, the level of the terminal input to the CPU 30 is fixed at "0", and this can be detected, and the input can be performed. When the voltage of any one of the phases of the power supply drops, the time of "1" of each phase changes.
It becomes possible to detect this.

Second Embodiment In the second embodiment, the same circuit as that of the first embodiment is used. That is, as shown in FIGS. 1 and 2, since it is possible to record the rising time of each terminal of the internal timer 33, it is possible to record from the rising of the R phase to the S
Until the rising of the phase (or S phase-T phase, T phase-R
It is possible to detect the phase difference of (phase). At the same time, the state of each phase can be known from the level of each terminal.

When the input power supply is out of phase and the input voltage is completely zero, the level of the terminal input to the CPU is "0".
Since it is fixed to, it becomes possible to detect this,
Further, when a voltage drop occurs in one of the phases of the input power source, the phase difference changes, and this can be detected.

Third Embodiment In the third embodiment, the same circuit as in the first and second embodiments is used. The high-speed input terminal of the CPU 30 responds to rising or falling of each terminal so that it can perform immediate interrupt processing.

Therefore, it is detected how the states of the three phases change each time the falling edge and the falling edge occur, and if any of the phases does not match the predetermined pattern, one of the phases is missing. To determine. If the input power supply is completely open phase and the input voltage is zero, the CPU 30
Since the level of the terminal input to is fixed to "0", this can be detected.

Fourth Embodiment In the fourth embodiment, the circuits of FIGS. 1 and 5 are used. That is, the output of the line voltage detection of FIG. 6 is used for the input in the circuit of FIG. Phase input detector 1
As 0, the line voltage detection circuit shown in FIG. 5 is used.

The line voltage detection circuit, as shown in FIG.
Resistors 11 to 1 are provided between the lines of the power input R, S, and T phases.
3, photocoupler 17R (17S, 17T), diode 1 connected in antiparallel with the light emitting diode 15 of the photocoupler
A logic circuit 1 for detecting the on / off state of the phototransistor 16 and the resistor 18 of the photocoupler and the phototransistor 16 on the secondary side of which the primary side is constituted by a circuit composed of 4
9. By connecting in this way, it is possible to obtain a line voltage detection waveform that is turned on / off for each half cycle of the line voltage between R-S, S-T, and T-R. This line voltage detection waveform is input to the high speed input terminal of the CPU.

Using the internal timer 33 of the CPU 30, R
From the rising time when the detection voltage between −S becomes “1”,
It is possible to detect the phase difference until the rising time at which the detection voltage between S and T becomes 1, and also input to the CPU 30 to know the state between the level lines of the terminals.
The same applies to other lines.

When the input power supply is open-phase and the input voltage is completely zero, the level of the terminal input to the CPU is fixed to 0, which makes it possible to detect this and also to detect the input power supply. When a voltage drop occurs in any of the phases, the phase difference between the lines changes, and this can be detected.

Fifth Embodiment In the fifth embodiment, the output of the detection of the line voltage shown in FIG. 5 is used as the input of the circuit in FIG. The waveform of the line voltage detection is R phase "1", S phase "0" output "1", S phase "1", S phase "1", T phase "0",
The output 1 is input to the logic that becomes the output 1 at the T phase “1” and the R phase “0”, and this output is input to the gate input terminal of the counter 21 and the input terminal of the CPU 30.

It is possible to detect the phase difference from the rising time at which the detection voltage between R and S becomes 1 to the rising time at which the detection voltage between S and T becomes 1, and in addition, C
It is possible to know the state between the levels of terminals by inputting to the PU 30. The same applies to other lines.

When the input power supply is out of phase and the input voltage is completely zero, the level of the terminal input to the CPU 30 is fixed at "0", and this can be detected, and the input can be performed. When a voltage drop occurs in any phase of the power supply, the phase difference between the lines changes, which can be detected.

[0036]

As described above, the present invention is capable of preventing malfunction of a relay or the like and performing stable and reliable operation of the inverter by detecting the open phase and protecting the inverter during the operation of the inverter.

By applying the present invention to the open-phase detecting circuit of the inverter, the adjustment becomes unnecessary and the hardware can be greatly simplified. Further, the power supply section and the control circuit section are insulated from each other by a photocoupler so that noise resistance is improved and no special device for conducting a withstand voltage / insulation resistance test of the main circuit section is required.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an arithmetic processing unit of a power supply phase loss detection apparatus according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a phase loss detection device.

FIG. 3 is an operation waveform diagram of the open phase detection device.

FIG. 4 is a block diagram of a power supply phase loss detection apparatus according to the present invention.

FIG. 5 is a circuit diagram of a phase input detection unit of the phase loss detection device.

FIG. 6 is a block diagram of a count processing unit of the power supply phase loss detection apparatus.

FIG. 7 is a block diagram of a conventional phase loss detection device for an elevator power supply.

[Explanation of Codes] 10 ... Phase Input Detection Unit 11 to 14 ... Resistor 14 ... Diode 15 ... Light Emitting Diode 16 ... Photosensitive Transistor 17R, 17S, 17T ... Photocoupler 18 ... Resistor 19 ... Logic Circuit 20 ... Count Processing Unit 21 ... Counter 22 ... logic circuit 30 ... arithmetic processing unit (CPU) 31 ... signal change detection unit 32 ... interrupt control unit 33 ... internal timer 34 ... time recording unit 35 ... open phase detection arithmetic unit

Claims (5)

[Claims] 1. A phase input detection unit that receives the voltage of each phase of a power supply and detects the state of the voltage of each phase, and a counting processing unit that counts the phase detection signal of the phase input detection unit as an input. And a phase detection signal of the phase input detection unit and a count processing signal of the count processing unit as an input to perform a calculation process, and to determine whether there is a missing phase of the power source. A signal state change detection unit that detects a change in the voltage detection signal of each phase of the power supply or between each phase, and records the change time of the voltage detection signal by inputting the detection signal of this signal change detection unit and the clock signal of the internal timer. A time recording unit, an interrupt processing unit that performs interrupt processing by inputting the state change signal of the signal state change detection unit, and a phase loss detection that inputs the time signal of the time recording unit and the interrupt signal of the interrupt processing unit Phase detection calculation unit, An open-phase detecting device for a power supply, characterized by being configured by. 2. A phase photodetector, wherein each phase photodetector is composed of a light emitting diode connected to each phase of a power source input and a phototransistor for receiving light from the light emitting diode, and the light emitting diode of the photocoupler for each phase. Each of the diodes is connected in anti-parallel and a logic circuit that receives the output signal of the light receiving transistor as an input. The output sides of the light emitting diodes corresponding to the respective phases are commonly connected, and the logic circuits corresponding to the respective phases are used. 2. The power supply phase loss detection apparatus according to claim 1, further comprising phase voltage detection means for detecting a phase voltage. 3. The count processing unit is composed of a counter, and the arithmetic processing unit receives the phase voltage signal of the phase input detection unit as an input, and detects a phase loss of the power supply from the phase voltage signal and the count value of the counter. 2. An elevator power supply open-phase detection device according to claim 1, further comprising: 4. The counting processing section is composed of a logic circuit that performs a logical operation with each phase voltage signal of the phase input detection section as an input, and a counter that counts with a logic operation output signal of this logic circuit as an input. The power supply phase loss detecting device according to claim 1. 5. The power supply phase loss detection device according to claim 1, wherein the phase input detection unit is configured by a line voltage detection unit that detects a line voltage of the power supply.