JP2002058290A - Method for detecting abnormality of engine generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for detecting abnormality of an engine generator in which a control circuit is protected by detecting an abnormality due to improper connection of commercial power supply surely and instantaneously. SOLUTION: The method for detecting abnormality of an engine generator based on the connection of commercial power supply comprises a generator 1 coupled with an engine 10, a voltage stabilizing circuit 2 for stabilizing the output of the generator 1 through DC conversion, an inverter circuit 3 for AC converting the output of the voltage stabilizing circuit 2, and a filter circuit 4 connected to the output side of the inverter circuit 3 wherein the voltage stabilizing circuit 2 includes, on the output side thereof, a capacitor 12 and a voltage sensor 5 for detecting the voltage across the capacitor, and the inverter circuit 3 comprises a plurality of elements 13 having commutation function. A decision is made that an abnormality has occurred due to improper connection of commercial power supply when a voltage detected by the voltage sensor 5 exceeds a predetermined threshold level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an abnormality in an engine generator, and more particularly to a method for detecting an abnormality based on connection to a commercial power supply.

[0002]

2. Description of the Related Art An inverter-type engine generator for driving a generator by rotating the engine includes a generator connected to an engine, a voltage stabilizing circuit for converting the output of the generator into DC and stabilizing the output, An inverter circuit for converting an output of the stabilizing circuit into an alternating current, and 100 V of a predetermined frequency (50 Hz or 60 Hz) via a filter.
AC voltage is obtained. This inverter circuit includes a current sensor for detecting a load current in order to control a power generation amount according to a load.

[0003] Such an engine generator can obtain an AC voltage having the same frequency as that of a household commercial power supply of 100 V. Therefore, such an engine generator is an improper use method that is normally prohibited by a manual or the like. In some cases, the output terminal is plugged into a household power outlet and the outlet is used to supply power to the home. In such a case,
When the power outage is restored, electric power from the commercial power supply is supplied from the outlet to the generator side, and the control circuit in the generator may be burned.

Conventionally, in order to detect such an abnormality based on improper connection of the commercial power supply, when a current sensor provided in the inverter circuit detects a sudden increase in the current, it is determined that the current from the commercial power supply has flowed. Therefore, the control circuit was shut down to stop the power generation operation.

[0005]

However, in the conventional method of detecting an abnormality in connection with a commercial power supply using a current sensor, there is a case where a function is stopped by judging an inrush current due to an inductive load in a normal use state as abnormal. In some cases, an abnormal judgment could not be made accurately. In this case, since the rush current disappears or attenuates after a certain time has elapsed, the rush current can be detected by providing a certain detection time. After the detection time has elapsed, the rush current can be identified and the operation can be continued as it is. However, consuming such a detection time does not sufficiently protect the internal circuit when current flows due to the connection of the commercial power supply.

The present invention has been made in consideration of the above-mentioned prior art, and provides an abnormality detection method for an engine generator which protects a control circuit by instantaneously and reliably detecting an abnormality caused by inappropriate connection of a commercial power supply. Aim.

[0007]

According to the present invention, there is provided a generator connected to an engine, a voltage stabilizing circuit for converting the output of the generator into a direct current and stabilizing the generator. An inverter circuit for converting an output of the stabilizing circuit into an alternating current; and a filter circuit connected to an output side of the inverter circuit, wherein the voltage stabilizing circuit has a capacitor at its output side and a voltage between both ends thereof. The inverter circuit comprises a plurality of elements having a rectifying function, wherein the detected voltage of the voltage sensor is a predetermined threshold value. An abnormality detection method for an engine generator is characterized in that it is determined that an abnormality is caused by connection of a commercial power supply when a voltage is exceeded.

According to this configuration, by detecting the voltage between both ends of the capacitor provided in the voltage stabilizing circuit, when the voltage of the capacitor becomes higher than a predetermined value, the abnormality due to the connection of the commercial power supply is immediately and surely made. It is determined and the reliability of abnormality detection is increased. In this case, even if an inrush current based on the inductive load in a normal use state flows, the capacitor voltage is not affected, so that the function is not stopped due to erroneous detection and normal use is continued.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a drive control circuit (controller) of an engine generator according to an embodiment of the present invention, and FIG. 2 is a circuit diagram thereof.

A three-phase generator 1 is connected to an engine 10 (FIG. 2). A DC conversion circuit / voltage stabilizing circuit 2 is connected to the output side of the generator 1, and an inverter circuit 3 is connected to the output side.
Is connected. The inverter circuit 3 is connected to the output terminal 11 via the filter circuit 4 and extracts a voltage of 50 V or 60 Hz of 100 VAC. The DC conversion circuit / voltage stabilization circuit 2 converts a three-phase AC voltage into DC and stabilizes the voltage, and includes a capacitor 12 for maintaining a predetermined constant voltage. This capacitor 12
Is connected to a voltage sensor 5 for detecting the voltage between both ends.

The inverter circuit 3 includes a rectifier diode and an F
A bridge circuit is formed by the four switching elements 13 coupled with the ET, and converts a DC voltage into an AC. The inverter circuit 3 includes a current sensor 6 for detecting a load current in order to control a power generation amount according to a load. The output of the inverter circuit 3 is smoothed by the filter circuit 4, and as shown by P in FIG.
Taken out of

The voltage sensor 5 and the current sensor 6 are a CPU
The CPU 7 drives and controls the DC conversion circuit / voltage stabilizing circuit 2 and the inverter circuit 3 based on each detection signal. The CPU 7 further receives an engine speed signal from a speed sensor 9 of the engine 10 (or the generator 1) and, if necessary, detection signals from a temperature sensor (not shown), a throttle opening sensor (not shown), and the like. The driving of the engine 10 is controlled based on these. An abnormality warning lamp 8 is connected to the CPU 7 and lights up when an abnormality is detected.

In the drive control circuit having the above structure, when the output terminal 11 is improperly used, for example, when the output terminal 11 is plugged into an outlet of a commercial power supply for home use, when a commercial voltage of 100 V AC is applied, the capacitor is immediately turned on. The voltage across the terminal 12 increases. Therefore, when the detection voltage of the voltage sensor 5 exceeds the predetermined threshold, the CPU 7 can determine that the abnormality is caused by the connection of the commercial power supply. When detecting such an abnormality, the CPU 7 turns off the switching elements 13 of the inverter circuit 3 to stop the circuit operation of the generator 1 to prevent the flow of the commercial current into the control circuit, and also turns on the abnormality warning lamp 8. I do. This protects each element in the control circuit and informs the user of an abnormal state.

FIG. 3 is an explanatory diagram of an abnormality detection voltage by the capacitor 12. (A) shows the voltage across the capacitor 12 in the control circuit (controller) during normal use. Under normal conditions, this DC voltage is a constant value corresponding to the rated output of the generator (1 in this example).
80V). Therefore, 200V somewhat higher than 180V is set as the threshold value of the abnormality detection voltage.

(B) shows an AC voltage curve of a commercial power supply.
The peak value of the commercial power supply having an effective value of 100 V is ± 140 V as shown. When this AC commercial voltage is applied to the control circuit, it is rectified by the above-described inverter circuit 3 (FIG. 2), the phase is inverted and becomes a + voltage, and is superimposed on the capacitor voltage of (A). This state is shown in FIG. This voltage is detected by the voltage sensor 5 (FIG. 2), and the CPU 7 determines that the voltage exceeds the threshold value of 200 V and detects an abnormality.

FIG. 4 is a flowchart of an abnormality detection routine by the CPU 7. This routine is an interrupt process to the main control program. The abnormality detection routine is interrupted and executed during the operation of the control circuit by the program timer management (step S1).
First, data of the DC voltage across the capacitor detected by the voltage sensor 5 is read (step S2). Subsequently, it is determined whether or not the DC voltage is higher than the threshold value 200V (step S3). If it is equal to or less than the threshold value, it is in a normal operation state, and the program exits the routine and continues the main program. If the threshold value exceeds 200 V, it is determined that an abnormality has occurred, the operation of the drive circuit is stopped, the output is stopped, and the abnormality warning lamp 8 (FIG. 2) is turned on (step S).
4).

[0017]

As described above, according to the present invention, by detecting the voltage between both ends of the capacitor provided in the voltage stabilizing circuit, when the voltage of the capacitor becomes higher than a predetermined value, the commercial power supply is detected. An abnormality due to the connection is immediately and reliably determined, and the reliability of abnormality detection is improved. In this case, even if an inrush current based on the inductive load in a normal use state flows, the capacitor voltage is not affected, so that the function is not stopped due to erroneous detection and normal use is continued.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control circuit of an engine generator according to an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a control circuit of FIG. 1;

FIG. 3 is an explanatory diagram of an abnormality detection voltage by the voltage sensor of the present invention.

FIG. 4 is a flowchart of an abnormality detection routine according to the present invention.

[Explanation of symbols]

1: generator, 2: DC conversion circuit / voltage stabilization circuit, 3:
Inverter circuit, 4: filter circuit, 5: voltage sensor,
6: current sensor, 7: CPU, 8: abnormality warning light, 9: rotation speed sensor, 10: engine, 11: output terminal, 12:
Capacitor, 13: switching element.

Continued on the front page (72) Inventor Keisuke Sugiura 2500 Shinkai, Iwata-shi, Shizuoka Prefecture F-term in Yamaha Motor Co., Ltd. (reference) 5G044 AA03 AC01 AD01 AE01 BA04 BA10 5H590 AA01 AB02 AB20 CA07 CA21 CA24 CD01 CD03 CE02 EB02 EB07 FC14 FC17 FC22 FC23 HA02 HA04 JA02

Claims (1)

[Claims] 1. A generator connected to an engine, a voltage stabilizing circuit for converting an output of the generator into DC and stabilizing the output,
An inverter circuit for converting an output of the voltage stabilizing circuit into an alternating current; and a filter circuit connected to an output side of the inverter circuit, wherein the voltage stabilizing circuit has a capacitor on its output side and a capacitor between both ends thereof. The inverter circuit comprises a plurality of elements provided with a rectifying function. The engine circuit includes a plurality of elements, and when the detected voltage of the voltage sensor exceeds a predetermined threshold voltage, An abnormality detection method for an engine generator, wherein the abnormality is determined as an abnormality due to power supply connection.