JP2000078775A - Emergency power source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a connected load against an overrun of an engine by detecting a frequency of an output voltage of a generator, comparing the frequency with a preset reference value, and stopping the engine for driving a generator at the time of detecting the overrun of the engine from the output voltage of the generator. SOLUTION: When a frequency of an AC from an output winding of a motor generator 1 becomes higher than a preset value, it is detected by an overrun detecting means 10, which outputs a signal of the overrun to an automatic drive control means 6. At this time, the means 6 sends a stop signal to the engine and forcibly stops the engine. Further, when it becomes an overvoltage during operating of the generator 1, there is a fear of damaging the load. Then, when it becomes the overvoltage with respect to a rated voltage of the generator, it is detected by an overvoltage detecting means 9, and the means 6 sends a stop signal to the engine to forcibly stop the engine, thereby protecting the load against its damage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emergency power supply unit integrally provided with an automatic switching control device capable of automatically switching to an emergency power generator when a commercial power supply fails.

[0002]

2. Description of the Related Art Conventionally, measures against a power failure of a commercial power
Usually, instantaneous recovery is often performed. For example, it is usually sufficient to make a backup using an uninterruptible power supply system using a battery as an emergency power supply. However, depending on the country, a long-term power outage often occurs, and an emergency power generator that can cope with a long-term power outage cannot respond with an uninterruptible power supply using a battery as described above. Needs were growing.

For this reason, an emergency power generator has conventionally been used. However, in the event of a power failure, switching to the power generator can be performed in response to a power failure of the commercial power supply by manually switching a changeover switch. Had been However, such a method has a simple configuration, but is not practical because switching takes time.

Conventionally, in an uninterruptible power supply used as a power supply for precision electronic equipment such as a computer, a generator is started in response to detection of a power failure, and when the power failure is restored, the original commercial power supply is restored. A technique for controlling the switching to the power supply and stopping the engine of the generator is known (see Japanese Utility Model Laid-Open No. 63-7945).

[0005] However, in this case, the switching control device corresponding to the power failure of the commercial power supply is a large-scale device that is installed as a facility and as a separate device, is expensive, and is expensive when an engine-related trouble occurs. The protection device is also complicated.

[0006]

An inexpensive and compact power source capable of automatically switching power sources that can be combined integrally by using the dead space of a portable power generator that is driven by an engine that has been conventionally known. That can provide a power supply unit for use in such an engine, with a view to using it as a normal portable power generator and using it as an emergency power supply unit by switching a switch. When the governor malfunctions and the engine overspeeds, the frequency of the generator output voltage fluctuates accordingly, which may adversely affect the connected load.

An object of the present invention is to protect a connected load from overspeeding of an engine in order to solve such a problem.

[0008]

SUMMARY OF THE INVENTION An emergency power supply unit according to the present invention is an automatic switching control unit which is integrally mounted by utilizing a space inside a housing incorporating an engine driven by an engine and its control unit. The automatic switching control device is electrically disconnected by operating a switch, so that the power generator and its control device can be used as a portable power generator. An automatic switching control device for outputting power to a load from a commercial power supply and a generator output, and outputting a control signal to the power switching unit and the power generator based on detection of energization or power failure of the commercial power supply; Automatic operation control means for detecting when power is supplied to the commercial power supply, supplying power to the load from the commercial power supply, detecting the power failure of the commercial power supply, starting the generator, and supplying power to the load. When the supply is switched to the generator side, and when the commercial power supply is restored, the power supply source is switched from the generator side to the commercial power supply side and the power supply source is controlled and the generator is stopped. Frequency detecting means for detecting the frequency of the engine, and means for comparing the frequency with a predetermined reference value. The generator is driven when overspeed of the engine is detected from the generator output voltage. It is characterized by stopping the engine.

The frequency detecting means is a circuit means for detecting a zero-cross point of the output voltage of the generator and generating a rectangular wave having a constant width from the zero-cross point, and judges whether or not the engine is overrunning. The means employs a technique of integrating circuit means for integrating the rectangular wave and comparison circuit means for comparing the output of the integration circuit with a reference value.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

FIG. 1 is a side view of a configuration in which an automatic switching control device, which is a feature of the present invention, is integrated with an engine generator and its control device, and FIG. 2 is a front view thereof.

The power generator and its control device other than the automatic switching control device are conventional ones known in the art.
For example, this means that a three-phase induction generator or a synchronous generator driven by the engine 4 is connected to an automatic voltage controller (AV).
R) to output single-phase or three-phase AC power. Further, the control device houses operation parts such as switches, output parts such as outlets, and status display parts such as meters. Such an engine-driven power generator and its control device are integrated into the housing 22 and used as a portable power generator. Exemplary case 2
Reference numeral 2 denotes a pipe frame formed by assembling a bent metal pipe or the like by welding or the like, and the engine 4, a small-capacity generator, and a control device are attached to the pipe frame. Such a so-called open frame type portable small power generator has a dead space, but the present invention makes effective use of the dead space and incorporates the automatic switching control device 5 integrally therewith. Things. As a result, the overall configuration can be made compact.

As shown in FIG. 2, a switching control panel 21 of the automatic switching control device is laid out in a similar design above the control box panel 20 of the power generator. Thereby, the operability is improved by setting the operation surface to the same side. Further, by simply switching the switch on the switching control panel 21 of the automatic switching control device, it can be used as a normal portable power generator, and can be used as an emergency power supply device as described in detail below. can do.

FIG. 3 shows an overall schematic block circuit diagram of the emergency power supply of the present invention. In the figure, a power generator 1 is of a type driven by an engine and having a built-in automatic voltage control device (AVR).
Includes operation parts such as outlets and switches for single-phase or three-phase output power of the generator, and display parts such as meters. The power switching unit 7 is a switch with a mechanical interlock that switches the power to the load side from a commercial power supply or a generator output. That is, this switch is on,
When the signal to turn off is output and the switch operates,
It is of the type that is held mechanically until the next operation signal is issued.

As will be described later in detail, the automatic operation control means 6 detects the energization of the commercial power supply by the power failure detection means 8, outputs an operation signal to the power switching unit 7 when necessary, and controls the power generator to operate. It outputs a signal to start and stop. The system power supply 11 has a constant voltage power supply circuit therein and supplies DC power to various circuits in the automatic switching control device 5. The display unit 13 illuminates various LEDs for monitoring the operating state, and displays, for example, that the battery is being charged, that the commercial power is being supplied, that the generator is operating, that the generator cannot be started, and the like. The operation unit 14 is provided with a changeover switch for enabling the automatic operation control means 6 to operate after confirming that the commercial power supply is energized by the display unit, a switch for switching between the portable power generator and the emergency power supply device, and the like. The switching signals of these changeover switches control the automatic operation control means 6, and
The power switching unit 7 and the like are controlled as needed.

When the commercial power supply is energized, the commercial power supply is applied to the automatic switching control device 5 via the transformer 15, and at the same time, the battery 3 is charged via the auxiliary charging circuit 12. After a predetermined time from the start of energization, for example, after 20 seconds,
An operation signal for turning on the commercial power supply side contact is output from the automatic operation control means 6 to the power switching unit 7, and as a result, the commercial power is supplied to the load via the power switching unit 7. Thereafter, the monitoring mode for automatically detecting a power failure of the commercial power supply can be set, or the monitoring mode can be set by turning on a changeover switch provided on the operation unit 14.

In the monitoring mode, if the commercial power supply is interrupted by lightning or the like, the power is not supplied to the load and the commercial power supply to the automatic switching control device 5 is not supplied at the same time. 5 includes a system power supply 11 that is automatically and continuously supplied from the charged battery 3.
Power is supplied via the. Thereby, the power failure detection means 8 outputs a power failure detection signal to the automatic operation control means 6,
Then, the automatic operation control means 6 outputs an off signal of the commercial power supply side contact, and disconnects the connection between the load side and the commercial power supply side by the power switching unit 7.

Immediately after a commercial power failure,
A start signal is sent from the automatic operation control means 6 to the starter of the engine of the power generator 1, whereby the starter starts, the engine rotates, and the power from the power generator 1 directly connected to the engine to the battery 3 is transferred. Charging is performed.

After a predetermined time from the start of the power generator 1,
For example, after about 15 seconds, a signal for turning on the generator-side contact is output from the automatic operation control unit 6 to the power switching unit 7, and as a result, power is supplied from the power generator 1 to the load side.

The operation timing at the time of the above power failure is shown in the upper part of FIG. The time is expressed in seconds (S), and it is assumed that a power failure occurs at 0 seconds. Blackout monitoring
In 0.1 seconds, the starter starts and at the same time the generator runs. The starter is operated intermittently as described later. After an interruption of about 15 seconds, the generator output rises, indicating that the power supply to the load switches from commercial power to generator output.

When the commercial power is restored in the generator operation mode, the commercial power is supplied to the automatic switching control device 5 via the transformer 15 and the battery 3 is charged. Then, a signal for switching the contact from the generator side to the commercial power side is output from the automatic operation control means 6 to the power switching section 7 for a predetermined time, for example, 20 seconds after the commercial power supply is restored. The contact turns on,
Then, with a slight delay of about 0.1 to 0.2 seconds, the generator stops almost simultaneously. The operation timing at the time of the power recovery is shown in the lower side of FIG. At 0 seconds, the commercial power supply is restored, and after 20 seconds, the generator operation is stopped. At the same time, the generator output is lost, and the power supply to the load is switched to the commercial power supply.

FIG. 5 is a diagram for explaining the protection of the circuit for taking measures against abnormalities characteristic of the present invention in the automatic switching control device 5 from over-rotating the engine. The overspeed detection means 10 receives a voltage signal from the output winding of the power generator 1 and outputs an on / off signal of the voltage to the automatic operation control means 6.

The AC voltage from the output winding of the motor generator 1 is half-wave rectified by the diode 101, and the resistors 102 and 10
The voltage is divided by 3 and input to the pin a of the monostable multivibrator 105 via the capacitor 104. The pin a serves as a trigger signal of the zero cross point at the trailing edge of the half-wave rectification by the action of the capacitor 104. From the b pin of the monostable multivibrator 105, a rectangular pulse for a fixed time is output from the trigger point of the a pin, and is integrated by the integrating circuit of the resistor 106 and the capacitor 107 to be a DC value.

Therefore, the DC value is determined by the frequency of the AC voltage from the output winding of the generator 1, and the DC value increases as the frequency increases. Operational amplifier 10
After the voltage and impedance are converted by the circuit of 8 and the resistors 109 and 110 to stabilize the DC value, the DC value is applied to the non-inverting input terminal of the operational amplifier 115 via the resistor 114. A constant voltage divided by the resistors 111 and 112 is connected to the inverting input terminal of the operational amplifier 115 by the resistor 1.
13 to generate a reference potential. Therefore, the operational amplifier 115 operates as a voltage comparator, and transmits a high or low voltage to the automatic operation control means 6 through the diode 116.

The constant voltage generator 117 generates a power supply for the circuit from the system power supply 11. The V terminal of each element is its + terminal, and the E terminal is grounded.

Therefore, when the frequency of the alternating current from the output winding of the generator 1 becomes higher than a preset value, in other words, the rotation speed of the engine driving the generator 1 is set in advance. If the rotation speed becomes higher than the preset rotation speed, an overspeed signal is output to the automatic operation control means 6. At this time, the automatic operation control means 6 sends a stop signal to the engine to forcibly stop the engine.

FIG. 6 is a diagram for explaining protection of the starter and the battery. As described above, the engine is turned off by a commercial power failure and a start signal is sent from the automatic operation control unit 6 to the starter. However, if the engine cannot be started for any reason such as lack of gas or lack of oil, If the starter is continuously rotated, the starter may be burned out due to an overcurrent, or the battery voltage may drop. Therefore, in order to eliminate such inconvenience, the starter start signal is intermittently repeated, for example, ON 3 seconds and OFF 6 seconds are repeated twice. If the engine still cannot be started, the supply of the start signal is interrupted. , The indicator on the display (the generator cannot be started LE
A signal is sent to D) to make it blink.

FIG. 7 is a diagram for explaining load protection at the time of generator overvoltage output. The constant voltage circuit (AVR) is broken during operation of the generator for some reason.
If an overvoltage occurs, the connected load may be broken. Therefore, if the voltage of the generator is, for example, approximately + 10% of the rated voltage, that is, as shown in the drawing, the overvoltage of 240 V is exceeded by the rated voltage of 220 V, this is detected by the overvoltage detecting means 9 in FIG. Then, a stop signal is sent from the automatic driving control means 6 to the engine to forcibly stop the engine and protect the load from being destroyed.

[0029]

According to the first aspect of the present invention, the generator includes a frequency detecting means for detecting the frequency of the generator output voltage, and a means for comparing the frequency with the preset reference value. Since the engine that drives the generator is stopped when overspeed of the engine is detected from the output voltage, the governor used in the engine malfunctions, and the engine overspeeds, causing the output voltage of the generator to decrease. Even if the frequency changes, the load can be protected without affecting the connected load.

Further, according to the second aspect of the present invention, the frequency detecting means detects a zero cross point of the generator output voltage, generates a rectangular wave having a constant width from the zero cross point, integrates the rectangular wave and sets a reference value by integrating the rectangular wave. By providing the comparison circuit means for comparing the values, the reference value only needs to change the circuit constant, and the engine can be easily adapted to different types of emergency power supply devices depending on the product.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of the configuration of an emergency power supply device according to the present invention in which an automatic switching control device is integrally incorporated together with a power generator and its control device.

FIG. 2 shows a front view of the configuration shown in FIG.

FIG. 3 shows an overall schematic block circuit diagram of the emergency power supply device of the present invention.

FIG. 4 is a diagram showing operation timings at the time of a power failure and at the time of power recovery.

FIG. 5 is a diagram illustrating protection of the engine from over-rotating according to the present invention.

FIG. 6 is a diagram for describing protection of a starter and a battery.

FIG. 7 is a diagram for explaining load protection at the time of generator overvoltage output.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Activation generator 2 Control device 3 Battery 4 Engine 5 Automatic switching control device 6 Automatic operation control means 7 Power switching unit 8 Power failure detection means 9 Overvoltage detection means 10 Overspeed detection means 11 System power supply 12 Auxiliary charging circuit 13 Display unit 14 Operation Part 15 Transformer 20 Control box panel 21 Switching control panel 22 Housing

Claims (2)

[Claims] 1. An automatic switching control device which is integrally mounted by utilizing a space inside a housing incorporating a motor generator driven by an engine and a control device thereof,
The automatic switching control device is electrically disconnected by operating a switch, and the power generator and its control device are used as a portable generator, and the automatic switching control device supplies electric power to a load with a commercial power supply. A power switching unit for switching from a generator output, and control means for outputting a control signal to the power switching unit and the power generator based on detection of energization or power failure of the commercial power supply. Detects and supplies power to the load from the commercial power supply, detects the power failure of the commercial power supply, starts the power generator, switches the power supply to the load to the generator side, and returns the power to the commercial power supply. Detecting this, the frequency of the generator output voltage is detected in the emergency power supply device that switches the power supply source from the generator side to the commercial power supply side and controls the generator to stop. And the wave number detecting means, a comparator means for comparing the reference value, the generator emergency power supply apparatus characterized by stopping the engine to drive the generator when the output voltage overspeed of the engine from is detected. 2. The frequency detecting means is a circuit means for detecting a zero cross point of the generator output voltage and generating a rectangular wave having a constant width from the zero cross point,
2. The apparatus according to claim 1, wherein the means for determining whether the engine is overspeeding is an integrating circuit means for integrating the rectangular wave and a comparing circuit means for comparing an output of the integrating circuit with a reference value. Emergency power supply.