JP4186887B2 - Earth leakage detector - Google Patents

Description

  The present invention relates to a leakage detection device that detects leakage of an AC power supply device that includes an AC generator and a power converter that converts the output of the AC generator into an AC output having a constant frequency and supplies the output to a load. .

As a device for detecting a leakage (ground fault) of a power supply device using an AC generator as a power source, as shown in Patent Document 1 and Patent Document 2, a neutral point of an armature winding of a three-phase AC generator A leakage detection device has been proposed in which a leakage current is detected by detecting a zero-phase current flowing through a ground line connecting between the ground and the ground.
JP-A-10-142282 JP 2000-149758 A

  As shown in Patent Document 1 and Patent Document 2, in a leakage detection device that detects a leakage from a zero-phase current that flows through a ground line that grounds a neutral point of a generator when a leakage occurs, the leakage detection device When it is necessary to install the cable at a location away from the generator, it is necessary to route a long grounding wire that grounds the neutral point from the generator to the installation location of the leakage detection device. There was a problem of being troublesome.

  When the AC generator armature winding has no neutral point, for example, when the three-phase armature winding is Δ-connected, or when the generator is a single-phase AC generator, The proposal of could not be applied.

  In addition, in order to take necessary measures when a leakage occurs, it is desirable to be able to determine where the leakage (ground fault) has occurred in the power supply device, but the conventional leakage detection device Then, it was not possible to determine where the leakage occurred.

  The purpose of the present invention is not only to detect the occurrence of electric leakage at a location away from the AC generator, but to determine the location where the electric leakage has occurred, without extending the wiring leading to the neutral point of the generator for a long time. It is another object of the present invention to provide a leakage detecting device that can also perform the above-mentioned.

  Another object of the present invention is to provide a leakage detecting device capable of detecting the occurrence of a leakage even when the generator does not have a neutral point and determining the location where the leakage has occurred. Is to provide.

  The present invention is applied to a leakage detection device for an AC power supply device including an AC generator and a power converter that converts the output of the AC generator into an AC output having a constant frequency and supplies the AC converter to a load. The power supply device to which the leakage detection device according to the present invention is applied may be any device including an AC generator and a power converter that converts the output of the AC generator into an AC output having a constant frequency. Is optional. A representative power supply device suitable for applying the leakage detection device of the present invention includes a converter that converts an output of an AC generator into a DC voltage, an inverter that converts a DC voltage obtained from the converter into an AC voltage, and However, the present invention is not limited to this.

  In the present invention, a detection point forming circuit that forms a detection point coupled to each output line of an AC generator through a high impedance element, a voltage detection circuit that detects a voltage between the detection point and ground, and a voltage detection circuit A leakage detection means for detecting that a leakage has occurred when the detected voltage is equal to or higher than a reference voltage, and a leakage occurrence location determination means for determining a leakage occurrence location from the waveform of the voltage between the detection point and ground. Provided.

  When the alternator is a three-phase alternator, in a preferred aspect of the present invention, one of the three-phase output lines of the alternator is connected to one end, and the other end is connected in common. The detection point forming circuit is configured by a resistor, and a common connection point of the three resistors is used as a detection point.

  Further, when the AC generator is a single-phase AC generator, in a preferred embodiment of the present invention, the detection point forming circuit is configured by a resistance voltage dividing circuit connected between two output lines of the AC generator, The voltage dividing point of the resistance voltage dividing circuit is used as a detection point.

  As described above, a detection point coupled to each output line of the AC generator through a high impedance element is provided, and when a voltage between the detection point and the ground is detected, the detection point The voltage between the grounds is almost 0 level, and when a power leak occurs in the power supply device, the voltage between the detection point and the ground becomes equal to or higher than the threshold value. Therefore, the voltage between the detection point and ground can be detected, and when the detected voltage is less than the reference voltage set to an appropriate value, it can be detected that there is no leakage in the power supply unit. It is possible to detect that a leakage has occurred when the measured voltage is equal to or higher than the reference voltage.

  With the above configuration, a long grounding wire can be used because the detection point forming circuit can be coupled to the output line of the generator in the vicinity of the installation location of the leakage detection device without routing the wiring connected to the neutral point of the generator. Therefore, the leakage of the power supply device can be detected at a location away from the generator. In addition, even when the armature coil of the generator does not have a neutral point, the leakage can be detected.

  Further, when the detection point is provided as described above, the voltage appearing between the detection point and the ground when a leakage (ground fault) occurs shows a different waveform depending on the location where the leakage occurs. That is, when a leakage occurs between the AC generator and the power converter, a voltage having a waveform whose period coincides with the period of the output voltage of the AC generator appears between the detection point and the ground. When a leakage occurs on the output side of the power converter, an AC voltage having a waveform whose period coincides with the period of the AC voltage output from the power converter appears between the detection point and the ground. Therefore, the cycle of the voltage appearing between the detection point and the ground when a leakage is detected matches the cycle of the output voltage of the AC generator, or equal to the cycle of the AC voltage output from the power converter. By checking whether it has been done, it can be determined whether a leakage has occurred in the circuit between the generator and the power converter or on the output side of the power converter.

  Therefore, the leakage occurrence location determination means is configured to cause leakage in the circuit between the AC generator and the power converter when the cycle of the voltage between the detection point and the ground matches the cycle of the output voltage of the AC generator. It can be configured to determine that

  The leakage occurrence location determination means is configured to determine that a leakage has occurred on the output side of the power converter when the cycle of the voltage between the detection point and the ground does not match the cycle of the output voltage of the AC generator. You can also.

  The leakage occurrence location determining means is that leakage has occurred in the circuit between the AC generator and the power converter when the cycle of the voltage between the detection point and the ground matches the cycle of the output voltage of the AC generator. It can also be configured to determine that leakage has occurred on the output side of the power converter when the period of the voltage between the detection point and the ground does not match the period of the output voltage of the AC generator.

  The leakage occurrence location determination means also determines that a leakage has occurred in the circuit on the output side of the power converter when the cycle of the voltage between the detection point and the ground matches the cycle of the output voltage of the power converter. It can also be configured as follows.

  The leakage occurrence location determination means also generates a leakage in the circuit between the AC generator and the power converter when the period of the voltage between the detection point and the ground does not match the period of the output voltage of the power converter. It can also be configured to determine that it has occurred.

  The leakage occurrence location determination means determines that a leakage has occurred on the output side of the power converter when the cycle of the voltage between the detection point and ground matches the cycle of the output voltage of the power converter, and It is also possible to determine that a leakage has occurred in the circuit between the AC generator and the power converter when the period of the voltage between them does not match the period of the output voltage of the power converter.

  In order to facilitate the detection of leakage, the detection voltage output by the voltage detection circuit is compared with the reference voltage, and the leakage detection pulse that shows different levels when the detection voltage exceeds the reference voltage and when it is below the reference voltage It is preferable to provide a leakage detection pulse generating circuit for generating In this case, the leakage detection means can be configured to detect that leakage has occurred in the AC power supply device when it is detected from the leakage detection pulse that the detected voltage is equal to or higher than the reference voltage. The leakage occurrence location determining means can be configured to determine the location of occurrence of leakage from the waveform of the leakage detection pulse.

  The level of the reference voltage is appropriately set according to the level of the detection voltage obtained when the leakage occurs so that the leakage can be accurately detected. If an earth leakage is generated on the output side of the power converter or if an earth leakage occurs in the circuit between the alternator and the power converter, the alternator The level of the reference voltage is set to a level that is lower than the minimum value of the peak value of the detection voltage obtained when a leakage occurs in the circuit between the power converter and the power converter.

  When the reference voltage is set so that a leakage detection pulse is always generated when a leakage occurs between the AC generator and the power converter, the leakage detection location determination means has a period of the leakage detection pulse of the AC generator. It can be configured to determine that a leakage has occurred in the circuit between the AC generator and the power converter when it can be considered that the output voltage period is matched.

  In addition, when setting the reference voltage so that a leakage detection pulse is always generated when a leakage occurs between the AC generator and the power converter, the leakage detection location determination means uses a period of the leakage detection pulse as the AC generator. It can also be configured to determine that a leakage has occurred on the output side of the power converter when it can be considered that the output voltage period does not match.

  Furthermore, when the reference voltage is set so that a leakage detection pulse is always generated when a leakage occurs between the AC generator and the power converter, the leakage detection location determination means has a cycle of the leakage detection pulse of the AC generator. When it can be considered that the output voltage period of the AC generator is the same as the output voltage of the AC generator, it is determined that a leak has occurred in the circuit between the AC generator and the power converter. It can also be configured to determine that leakage has occurred on the output side of the power converter when it can be considered that they do not match.

  In addition, when setting the reference voltage so that a leakage detection pulse is always generated when a leakage occurs on the output side of the power converter, the leakage detection point determination means determines that the leakage detection pulse cycle is equal to the output voltage of the power converter. It can be configured to determine that a leakage has occurred in the circuit on the output side of the power converter when it can be considered that it matches the cycle.

  When the reference voltage is set so that a leakage detection pulse is always generated when a leakage occurs on the output side of the power converter, the leakage detection point determination means determines that the leakage detection pulse cycle is equal to the output voltage of the power converter. It can also be configured to determine that a leakage has occurred in the circuit between the AC generator and the power converter when it can be considered that they do not match the cycle.

  When the reference voltage is set so that a leakage detection pulse is always generated when a leakage occurs on the output side of the power converter, the leakage detection point determination means determines that the leakage detection pulse cycle is equal to the output voltage of the power converter. AC generator when it is determined that a leakage has occurred on the output side of the power converter when it can be considered to match the cycle, and the cycle of the leakage detection pulse does not match the cycle of the output voltage of the power converter It can also be configured to determine that a leakage has occurred in the circuit between the power converter and the power converter.

  As described above, according to the present invention, a detection point coupled to each output line of an AC generator through a high impedance element is provided, and the presence or absence of a leakage is detected from the voltage between the detection point and the ground. Therefore, it is possible to detect the leakage of the AC power supply device at a location away from the generator without drawing the wiring connected to the neutral point of the generator for a long time.

  Further, according to the present invention, there is an advantage that the leakage can be detected even when the armature coil of the AC generator does not have a neutral point.

  Further, according to the present invention, it is determined from the waveform of the voltage appearing between the detection point and the ground whether a leakage has occurred in the circuit between the generator and the power converter or on the output side of the power converter. Therefore, it is possible to identify the location where the electric leakage has occurred and take appropriate measures for security.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the embodiment shown in FIG. 1, an AC power supply device includes a three-phase AC generator 2 driven by an internal combustion engine 1 and a power converter 4 into which a three-phase AC output of the generator 2 is input through a three-phase switch 3. Is configured. The internal combustion engine 1 also serves as a prime mover that drives drive wheels of a vehicle (not shown). The power converter 4 is operated to supply power to an external load when the vehicle is stopped and the power generation mode is selected (when the switch 3 is closed). When the vehicle travel mode is selected (when the switch 3 is opened), the operation of the power converter 4 is stopped, and the output from the power supply device is stopped. The generator 2 is also driven when the vehicle is traveling, but the output generated by the generator 2 when the vehicle is traveling drives the electrical components necessary to charge the battery or operate the internal combustion engine as necessary. Or for driving an electrical component provided in a vehicle such as a headlamp.

  The three-phase alternator 2 is composed of, for example, a magnet-type alternator, and has three-phase armature coils Lu to Lw on the stator side. These three-phase armature coils are star-connected. Yes. When applying the leakage detection device of the present invention, each phase armature coil of the generator is separated from the ground potential portion. As shown in the figure, when the three-phase armature coils Lu to Lw are star-connected, the neutral point is separated from the ground circuit.

  The power converter 4 converts the input AC voltage into a DC voltage, a power supply capacitor Cd connected between the output terminals of the converter 4A, and converts the DC output of the converter 4A into an AC voltage having a constant frequency. Output terminal that is connected to the inverter circuit 4C, a filter 4C that removes harmonic components from the AC output of the inverter 4B, and a controller 4D that controls the inverter 4B. A load 5 is connected between 4a and 4b.

  The converter 4A is composed of, for example, a full-wave rectifier circuit including a diode bridge circuit, and converts the AC output of the generator 2 into a DC output. The inverter 4B comprises a full bridge type switch circuit in which each side of the H bridge is constituted by a switch element such as a MOSFET that can be turned on / off, and the filter 4C is a low-pass type comprising coils L1 and L2 and a capacitor C1. It consists of a filter circuit.

  The output lines 2u to 2w drawn from the end opposite to the neutral point of the three-phase armature coil of the AC generator 2 are three-phase contacts 3u, 3v and 3w, and a ground circuit contact 3e. Are connected to the three-phase input terminals of the converter 4A through the corresponding phase contacts of the mode switch 3 having four contacts, and the voltage between the DC output terminals of the converter 4A (the voltage across the capacitor Cd) is the DC of the inverter 4B. Applied between input terminals.

  The controller 4D includes a microprocessor, and performs on / off control of the switch element of the inverter 4B so as to output an AC voltage having a constant frequency from the filter 4C. The controller 4D has a command signal input terminal 4d1 to which a mode selection command for selecting whether the engine operation mode is the vehicle travel mode or the power generation mode is given. In the illustrated example, the command signal input terminal 4d1 is connected to a positive output terminal of a constant voltage power supply circuit (not shown) through a resistor Ra and grounded through a ground circuit contact 3e of the mode switch 3. The mode switch 3 is a switch that is manually or electrically operated so that the contacts 3u, 3V, 3w, and 3e are turned on and off in the same phase. The mode switch 3 is turned on when the internal combustion engine is operated in the power generation mode. It is turned off when driving in the vehicle travel mode.

  When the mode switch 3 is turned on, the mode signal input terminal 4d1 of the controller 4D is set to the ground potential, so that a power generation mode selection command is given to the controller 4D, and the mode switch 3 is turned off. Sometimes, a vehicle travel mode selection command is given to the controller 4D by setting the potential of the mode signal input terminal 4d1 of the controller 4D to a high level.

  The controller 4D controls the switch element of the inverter 4B so as to generate an AC output having a constant frequency from the power converter 4 when the power generation mode selection command is given, and the vehicle travel mode selection command is given. Sometimes, the control of the switching element of the inverter 4B is stopped, and the output of the AC voltage from the power converter 4 is stopped. The controller 4 </ b> D also constitutes a leakage occurrence location determination unit that determines a location where the leakage occurs when the occurrence of leakage is detected by a leakage detection device described later.

  Although not shown, an AC output detection circuit for detecting a voltage between the output terminals 4a and 4b of the power converter 4 is provided, and a detection output of the AC output detection circuit is input to the controller 4D. The microprocessor provided in the controller 4D has a rotational speed of the internal combustion engine required to keep the output voltage of the power converter detected by the AC output detection circuit at a set value when the power generation mode selection command is given. Is always calculated as the target rotational speed.

  Reference numeral 6 denotes an electronic control unit (ECU) that controls the internal combustion engine 1, and this electronic control unit is connected to the controller 4 </ b> D of the power converter 4 by a communication line 7. The controller 4D and the electronic control unit 6 are provided with communication means for performing serial communication with each other through the communication line 7, and the contents of the mode selection command given to the controller 4D and the microprocessor of the controller 4D when the power generation mode is selected. The information on the target rotational speed of the engine calculated by the above and the information on the leakage occurrence location determined by the leakage occurrence location determination means are provided to the electronic control unit 6 through the communication line 7.

  The electronic control unit 6 controls the rotation speed of the internal combustion engine 1 when operating the engine in the power generation mode in addition to controlling the ignition timing of the internal combustion engine and the fuel injection device that supplies fuel to the internal combustion engine. The rotational speed of the internal combustion engine 1 is controlled so as to keep the target rotational speed calculated by 4D.

  8 is a leakage detection device according to the present invention. This leakage detection device is connected to the three-phase output lines 2u to 2w of the AC generator 2 through high impedance elements, as shown in FIG. A detection point forming circuit 8A for forming D, a voltage detection circuit 8B for detecting a voltage between the detection point D and the ground, and when the voltage Vn detected by the voltage detection circuit 8B is less than a set reference voltage and the reference An earth leakage detection pulse generating circuit 8C for generating an earth leakage detection pulse Vs showing a level different from that when the voltage is equal to or higher than the voltage, and an AC power supply apparatus when it is detected from the earth leakage detection pulse Vs that the detection voltage Vn is equal to or higher than the reference voltage A leakage detection means 8D for detecting the occurrence of a leakage in the earth, and a leakage occurrence location determination means 8E for determining the location of the leakage from the cycle of the leakage detection pulse Vs.

  The detection point forming circuit 8A shown in FIG. 1 includes three three-phase output lines 2u to 2w of the AC generator 2, one end of which is electrically connected and the other end is commonly connected and star-connected. It consists of resistors Ru to Rw, and the common connection point of the three resistors Ru to Rw is used as the detection point D. When the resistance values of the resistors Ru to Rw are set equal, the potential at the detection point D becomes substantially equal to the potential at the neutral point n of the armature coils Lu to Lw of the generator. That is, the detection point D is a virtual neutral point of the power supply device. Therefore, in the state where the ground fault has not occurred in the power supply device, the ground voltage at the detection point D is almost zero, but when a ground fault occurs, a voltage appears between the detection point D and the ground. As a matter of course, the resistance values of the resistors Ru to Rw are set to a sufficiently large value so as not to cause a problem loss in the detection point forming circuit 8A.

  The illustrated voltage detection circuit 8B includes a resistance voltage dividing circuit including resistors R1 and R2 connected in series between the detection point D and the ground, and a resistor R3 having one end connected to the voltage dividing point of the resistance voltage dividing circuit. And a capacitor C2 connected between the other end of the resistor R3 and the ground, and a detection voltage Vn proportional to the voltage between the detection point D and the ground is output to both ends of the capacitor C2.

  The leakage detection pulse generation circuit 8C is a circuit that generates a leakage detection pulse Vs that indicates a different level depending on whether the voltage Vn detected by the voltage detection circuit 8B is less than a set reference voltage or more than a reference voltage. The leak detection pulse generating circuit 8C shown in the figure compares the detected voltage Vn with the reference voltage Vr by comparing the detected voltage Vn with the reference voltage Vr by comparing the detected voltage Vn with the reference voltage generating circuit 8c1 for generating a constant reference voltage Vr giving a judgment value. And a comparator CP that generates output signals having different levels depending on whether the voltage is low or high.

  The reference voltage generation circuit 8c1 shown in the figure is constituted by a voltage dividing circuit that divides the output voltage of a constant voltage power supply circuit (not shown) by resistors R4 and R5, and the reference voltage Vr obtained from this reference voltage generation circuit is compared. Is input to the inverting input terminal of the CP. The output voltage of the voltage detection circuit 8B is input to the non-inverting input terminal of the comparator CP through the diode D1. The comparator CP shows a low level (L level) when the detection voltage Vn is lower than the reference voltage Vr, and a leakage detection pulse showing a high level (H level) when the detection voltage Vn is equal to or higher than the reference voltage Vr. Output Vs. The leakage detection pulse Vs output from the comparator CP is given to the microprocessor of the controller 4D.

  The microprocessor of the controller 4D detects that a leakage has occurred in the power supply device when detecting that the detection voltage Vn has become equal to or higher than the reference voltage Vr from the level change of the leakage detection pulse Vs. The leakage detection means 8D is configured by performing the determination process. The microprocessor also determines whether leakage has occurred in the circuit between the AC generator 2 and the power converter 4 or in the circuit on the output side of the power converter 4 from the cycle of the leakage detection pulse Vs. In the process of performing this determination process, the leakage occurrence location determination means 8E is configured.

  In the illustrated example, the mode switch 3, the components of the power converter 4, and the components of the leakage detector 8 are housed in a common case and unitized as an inverter unit 10.

  In the embodiment shown in FIG. 1, a magnet generator having a three-phase armature coil is used as the AC generator 2, the output voltage of the power converter 4 is set to 100 [V], and the frequency is set to 50 [Hz]. The results of observing the detection voltage Vn obtained from the voltage detection circuit 8B in the case where no ground fault occurs in the apparatus and the case where a ground fault occurs are shown in FIGS. The detection voltage Vn obtained from the voltage detection circuit 8B when no ground fault has occurred in the power supply device is maintained at almost 0 level as shown in FIG. At this time, since the detection voltage Vn cannot reach the reference voltage Vr, the output of the comparator CP maintains a low level (L level) as shown in FIG. In FIG. 4A, Vac represents the output voltage of the power converter 4.

  On the other hand, when a ground fault occurs at the point X1 of the circuit on the output side of the power converter 4 in FIG. 1, the detected voltage Vn becomes the power converter 4 as shown in FIG. The output voltage Vac has an AC waveform having the same frequency, and the cycle Tn of the detection voltage Vn coincides with the cycle Tac of the output voltage Vac of the power converter 4. At this time, since the detection voltage Vn exceeds the reference voltage Vr, the comparator CP generates a leakage detection pulse Vs indicating different levels when the detection voltage Vn exceeds the reference voltage Vr and when it is equal to or lower than the reference voltage. In this embodiment, as shown in FIG. 5B, when the detection voltage Vn exceeds the reference voltage Vr, the leakage detection pulse Vs becomes a high level (H level), and the detection voltage Vn is equal to or less than the reference voltage Vr. At this time, the comparator CP is provided so that the leakage detection pulse Vs is at a low level.

  Further, in the present embodiment, the leakage detection pulse Vs is detected in both cases where a leakage occurs on the output side of the power converter 4 and when a leakage occurs in the circuit between the AC generator 2 and the power converter 4. The level of the reference voltage Vr is set so that.

  In the power supply device of FIG. 1, point X2 on the downstream side (power converter side) of the circuit between the AC generator 2 and the power converter 4 or the upstream side (generator side) of the mode switch 3 6), the detected voltage Vn obtained from the voltage detection circuit 8B is an AC waveform having the same frequency as the output voltage of the AC generator 2, as shown in FIG. 6A. Presents. The peak value of the detection voltage Vn increases as the output voltage of the generator 2 increases.

  Also in this case, since a period in which the detection voltage Vn exceeds the reference voltage Vn occurs, the comparator CP shows a low level when the detection voltage Vn is less than the reference voltage Vr, and the detection voltage Vn becomes equal to or higher than the reference voltage Vr. A leakage detection pulse Vs indicating a high level is output when the power is on.

  As described above, the voltage VD between the detection point D and the ground is maintained at almost 0 level when the ground fault is not generated in the power supply apparatus, and is high when the ground fault is generated in the power supply apparatus. For the sake of illustration, whether or not a leakage has occurred in the power supply device by detecting the voltage VD between the detection point D and the ground and determining whether or not the detected voltage Vn is equal to or higher than the set reference voltage Vr. Can be detected.

  As shown in the figure, the leakage detection pulse generation circuit 8C generates a leakage detection pulse Vs indicating a low level when the detection voltage Vn is lower than the reference voltage Vr and indicating a high level when the detection voltage Vn is higher than the reference voltage Vr. In this case, it is possible to determine that a leakage has occurred in the power supply when the leakage detection pulse Vs has been detected by the microprocessor of the controller 4D, and thus the level of the leakage detection pulse can be determined. The leakage detection means 8D can be configured by the process of determining and determining whether or not leakage has occurred.

  Further, in the present embodiment, the microprocessor 4D of the controller 4D performs a process of determining whether or not it can be considered that the cycle of the leakage detection pulse Vs matches the cycle of the output voltage of the power converter 4. The leakage occurrence location determination means 8E is configured to determine the location. That is, by comparing the cycle of the leakage detection pulse with the cycle of the output voltage of the power converter 4, the location of occurrence of the leakage is determined.

  Whether or not it can be considered that the cycle of the leakage detection pulse coincides with the cycle of the output voltage of the power converter 4 is determined based on the detected value of the cycle of the leakage detection pulse and the cycle of the output voltage of the power converter (constant). Can be performed by determining whether or not the deviation is within the set error range. The period of the leakage detection pulse can be detected by counting the time from each rising edge of the leakage detection pulse to the next rising edge with a timer.

  When determining the location of leakage occurrence by comparing the cycle of the leakage detection pulse Vs with the cycle of the output voltage of the power converter 4, the leakage occurrence location determination means 8 </ b> E indicates that the cycle of the leakage detection pulse Vs is the power converter 4. It is determined that a leakage has occurred on the output side of the power converter 4 when it can be considered that the output voltage period coincides with the output voltage period, and the period of the leakage detection pulse Vs does not match the output voltage period of the power converter 4. It can be configured to determine that leakage has occurred in the circuit between the AC generator 2 and the power converter 4 when it can be considered.

  When detecting the presence or absence of leakage in the circuit between the AC generator and the power converter and the presence or absence of leakage on the output side of the power converter, it is not necessarily between the AC generator and the power converter. It is not necessary to perform both the determination process for the occurrence of electric leakage in the circuit and the determination process for the occurrence of electric leakage on the output side of the power converter. It is possible to know the result of the determination process. In addition, it is not always necessary to detect that a leak has occurred at a specific location and to detect that a leak has not occurred, but to detect that a leak has occurred at a specific location. Or only detection that no leakage has occurred at a specific location.

  Accordingly, the leakage occurrence location determination means 8E, for example, detects that a leakage has occurred in the circuit on the output side of the power converter 4 when the cycle of the leakage detection pulse Vs can be regarded as matching the cycle of the output voltage Vac of the power converter 4. It can be configured to determine that it has occurred.

  Moreover, when the cycle of the leakage detection pulse Vs does not coincide with the cycle of the output voltage Vac of the power converter 4, it is determined that a leakage has occurred in the circuit between the AC generator 2 and the power converter 4. The occurrence location determination means 8E can also be configured.

  In addition, when the leakage occurrence location determination means 8E can be considered that the cycle of the leakage detection pulse Vs coincides with the cycle of the output voltage of the AC generator, a leakage has occurred in the circuit between the AC generator and the power converter. It is possible to determine that leakage has occurred on the output side of the power converter when it can be considered that the cycle of the leakage detection pulse does not match the cycle of the output voltage of the AC generator. Whether or not it can be considered that the cycle of the leakage detection pulse coincides with the cycle of the output voltage of the AC generator is determined by detecting the detection value of the cycle of the leakage detection pulse and the detection value of the cycle of the output voltage of the AC generator ( This can be done by determining whether or not the deviation is 0 or within a set error range. The detection of the cycle of the output voltage of the alternator is performed, for example, by converting the detection waveform of the output voltage of the alternator into a rectangular wave, and the time from each rising edge of the rectangular wave to the next rising edge or each rising edge of the rectangular wave. This can be done by counting the time from the fall to the next fall with a timer.

  The cycle of the output voltage of the AC generator can also be calculated from the rotational speed of the internal combustion engine. That is, the period of the output voltage of the AC generator can be obtained by dividing the rotational speed N [rpm] of the internal combustion engine by the number of magnetic poles p of the AC generator 2. When the internal combustion engine is controlled using a microprocessor, usually means for detecting the rotational speed of the internal combustion engine is provided. Therefore, when the cycle of the output voltage of the generator is obtained by the above calculation, it is not necessary to provide a special detection circuit or operate a timer to obtain the cycle, and the output voltage of the generator The period can be easily detected.

  In addition, when the leak detection pulse cycle coincides with the output voltage cycle of the alternator, the leak occurrence point determination means 8E is determined so that it is determined that a leak has occurred in the circuit between the alternator and the power converter. Can be configured.

  Furthermore, the leakage occurrence location determination means 8E may be configured to determine that leakage has occurred on the output side of the power converter when the cycle of the leakage detection pulse does not coincide with the cycle of the output voltage of the AC generator. it can.

  Whether or not the cycle of the leakage detection pulse Vs and the cycle of the output voltage of the AC generator 2 coincide with each other is obtained by acquiring information on the rotational speed of the internal combustion engine from the ECU 6 and the cycle of the leakage detection pulse Vs is This can be done by determining whether or not the rotational speed N [rpm] of the internal combustion engine is equal to the value (= N / p) obtained by dividing the rotational speed N [rpm] by the number of magnetic poles of the AC generator 2. That is, when the cycle Tcp of the leakage detection pulse matches N / p, it can be determined that the cycle of the leakage detection pulse matches the cycle of the output voltage of the AC generator 2. When the cycle Tcp does not match N / p, it can be determined that the cycle of the leakage detection pulse does not match the cycle of the output voltage of the AC generator 2.

  In the embodiment shown in FIG. 1, the location of occurrence of leakage is determined from the cycle of leakage detection pulse Vs. However, in the present invention, the location of leakage is determined from the cycle of voltage between detection point D and ground. As shown in FIG. 3, the waveform of the voltage detection signal Vn obtained from the voltage detection circuit 8B is processed by a microprocessor, and the period of the voltage detection signal Vn is the period of the output voltage of the AC generator. It is also possible to make the determination of the location where the leakage occurs by determining whether or not it is consistent with the output cycle of the power converter.

  When a ground fault occurs in the circuit on the output side of the power converter 4, as shown in FIG. 5, the period of the voltage between the detection point D and the ground (the period of the detection voltage Vn) Tn is the power converter 4. Is equal to the cycle Tac of the output voltage Vac. When a ground fault occurs in the circuit between the AC generator 2 and the power converter 4, as shown in FIG. 6, the period of the voltage between the detection point D and the ground (the period of the detection voltage Vn). Coincides with the cycle of the output voltage of the AC generator 2. Therefore, by checking whether the cycle of the detection voltage Vn matches the cycle of the output voltage of the power converter 4 or whether it matches the cycle of the output voltage of the AC generator, the power converter 4 It is possible to determine whether a leakage has occurred in the circuit on the output side or whether a leakage has occurred in the circuit between the AC generator and the power converter.

  In this case, the leakage occurrence location determination means 8E determines whether the alternator 2 and the power converter 4 are connected when the cycle of the voltage VD between the detection point D and the ground coincides with the cycle of the output voltage of the alternator 2. It is determined that a leak has occurred in the circuit between them, and a leak has occurred on the output side of the power converter 4 when the cycle of the voltage VD between the detection point D and the ground does not match the cycle of the output voltage of the AC generator 2 It can be configured to determine that

  When it is only necessary to detect that a leakage has occurred in the circuit between the AC generator 2 and the power converter 4, the cycle of the voltage VD between the detection point D and the ground (the cycle Tn of the detection voltage Vn) is AC. The leakage occurrence location determination means 8E can be configured to determine that leakage has occurred in the circuit between the AC generator 2 and the power converter when the cycle of the output voltage VG of the generator 2 coincides. .

  If it is sufficient to detect that leakage has been detected on the output side of the power converter 4, the cycle of the voltage VD between the detection point D and the ground does not match the cycle of the output voltage VG of the AC generator. The leakage occurrence location determination means 8E can be configured to determine that leakage has occurred on the output side of the power converter 4 sometimes.

  Further, the leakage occurrence location determination means 8E determines that a leakage has occurred on the output side of the power converter 4 when the cycle of the voltage between the detection point D and the ground matches the cycle of the output voltage of the power converter 4. When the period of the voltage between the detection point D and the ground does not coincide with the period of the output voltage of the power converter 4, it is determined that a leakage has occurred in the circuit between the AC generator 2 and the power converter 4. It can also be configured as follows.

  As described above, when determining the location where the leakage occurs by checking whether the cycle of the voltage between the detection point D and the ground matches the cycle of the output voltage of the power converter 4, the power converter If it is only necessary to determine whether or not there is a leakage at the output side of the power converter 4, the period of the voltage VD between the detection point D and the ground coincides with the period of the output voltage of the power converter 4. The leakage occurrence location determination means 8E can be configured to determine that leakage has occurred in the output side circuit.

  When it is sufficient to determine whether or not there is a leakage in the circuit between the AC generator and the power converter, the cycle of the voltage VD between the detection point D and the ground is equal to the cycle of the output voltage of the power converter 4. When it is not done, the leakage occurrence location determination means 8E can be configured to determine that leakage has occurred in the circuit between the AC generator 2 and the power converter 4.

  Further, as shown in FIG. 1, when the switch 3 is inserted between the AC generator 2 and the power converter 4, the leakage detection means 8D generates leakage while the switch 3 is open. The leakage occurrence location determination means 8E can be configured to determine that leakage has occurred on the generator 2 side of the switch 3 when is detected.

  In the above embodiment, the resistance values of the resistors Ru to Rw constituting the detection point forming circuit 5A are made equal to make the ground potential at the detection point D substantially equal to the ground potential at the neutral point N of the AC generator. However, the detection point D may be any point as long as it is coupled to each output line of the generator through a high impedance element and has a potential different from the potential of any output line of the generator, and the resistance of the resistors Ru to Rw. The values do not necessarily have to be equal. When the resistance values of the resistors Ru to Rw are made different, there is a difference between the ground voltage at the neutral point n of the armature coil and the ground voltage at the detection point D, but the armature coil of the AC generator Is provided in a non-grounded state, almost no voltage appears between the detection point D and the ground when no leakage occurs, and a high voltage is detected between the detection point D and the ground when a leakage occurs. Because it appears, it does not interfere with detection.

  In the example shown in FIG. 1, the detection point forming circuit 5A is coupled to the generator output line in the inverter unit, but the detection point forming circuit 5A is coupled to the generator output line outside the inverter unit. Of course you may.

  In the above embodiment, the armature coil of the alternator 1 is star-connected. However, when the alternator does not have a neutral point, that is, when the armature coil is Δ-connected, the electric leakage Can be detected without any problem.

  In the above embodiment, a three-phase alternator is used as the alternator 1. However, as shown in FIG. 7, a single-phase armature having both ends ungrounded as the alternator 2 is used. The present invention can also be applied when a single-phase AC generator having the coil Wa is used. When a single-phase AC generator is used as the AC generator 2, a resistance voltage dividing circuit comprising a series circuit of resistors R10 and R11 having a sufficiently large resistance value between the two output lines of the generator 2 is provided. The resistance voltage dividing circuit is connected to form a detection point forming circuit 8A, and the voltage dividing point of the resistance voltage dividing circuit is set as a detection point D. The output of the generator coil Wa is input to the power converter 4 through the contacts 3a and 3b of the mode switch 3. In this example, the converter 4A of the power converter 4 includes a single-phase bridge full-wave rectifier circuit. The other configuration of the embodiment shown in FIG. 7 is the same as that of the embodiment shown in FIG.

  Also in the example shown in FIG. 7, the resistance values of the resistors R10 and R11 may be equal or different. It is only necessary that the potential of the detection point D is different from any of the two output lines of the generator.

  In each of the above embodiments, the detection point D is coupled to each output line of the AC generator through a resistor, but the detection point D is coupled to each output line of the AC generator through a high impedance element, What is necessary is just a point which shows the electric potential different from the electric potential of any output line of a generator. Therefore, the high impedance element that couples between the detection point D and each output line of the generator is not limited to the resistor.

  In the embodiment shown in FIG. 1, when a leakage (ground fault) occurs in the power converter 4, a DC voltage appears between the detection point D and the ground. When the positive output terminal of the converter 4a is grounded, a negative voltage appears between the detection point D and the ground. When the negative output terminal of the converter 4a is grounded, the detection point D is connected to the ground. A positive voltage appears at. Therefore, as necessary, when a DC voltage appears between the detection point D and the ground, the level is compared with the reference voltage to determine whether or not a leakage has occurred inside the power converter 4. Can do.

It is the circuit diagram which showed the structure of embodiment of this invention. It is the block diagram which showed the structure of the principal part of embodiment of FIG. It is the block which showed the structure of the principal part of other embodiment of this invention. In the embodiment shown in FIG. 1, the waveform of the detection voltage obtained from the voltage detection circuit when the ground fault has not occurred in the power supply device, the output voltage waveform of the power converter 4, and the output waveform of the leakage detection means are shown. FIG. FIG. 1 shows a waveform of a detection voltage obtained from a voltage detection circuit, an output voltage waveform of a power converter, and a waveform of a leakage detection pulse when a leakage occurs on the output side of the power converter in the embodiment shown in FIG. FIG. In the embodiment shown in FIG. 1, the waveform of the detection voltage obtained from the voltage detection circuit when a ground fault occurs in the circuit between the AC generator of the power supply device and the power converter, and the output voltage waveform of the power converter And a waveform diagram showing a waveform of a leakage detection pulse. It is the circuit diagram which showed the structure of other embodiment of this invention.

Explanation of symbols

2 AC generator 4 Power converter 4A Converter 4B Inverter 4C Filter 4D Controller 8 Leakage detection device 8A Detection point formation circuit 8B Voltage detection circuit 8C Leakage detection means 8D Leakage occurrence location determination means

Claims (17)

A leakage detecting device for an AC power supply device comprising: an AC generator; and a power converter that converts the output of the AC generator into an AC output having a constant frequency and supplies the AC converter to a load,
A detection point forming circuit that forms a detection point coupled to each output line of the AC generator through a high impedance element, a voltage detection circuit that detects a voltage between the detection point and ground, and a voltage detection circuit that detects the detection point A leakage detection means for detecting that a leakage has occurred when the voltage to be exceeded is equal to or higher than a reference voltage; and a leakage occurrence location determination means for determining a location of leakage from the period of the voltage between the detection point and ground. A leakage detection device for an AC power supply device.   The leakage occurrence location determination means is a circuit between the AC generator and the power converter when the cycle of the voltage between the detection point and ground matches the cycle of the output voltage of the AC generator. The leakage detection device according to claim 1, wherein the leakage detection device is configured to determine that leakage has occurred.   The leakage occurrence location determination means determines that a leakage has occurred on the output side of the power converter when the cycle of the voltage between the detection point and the ground does not match the cycle of the output voltage of the AC generator. The leakage detection device according to claim 1, which is configured as described above.   The leakage occurrence location determination means is a circuit between the AC generator and the power converter when the cycle of the voltage between the detection point and ground matches the cycle of the output voltage of the AC generator. It is determined that a leakage has occurred, and it is determined that a leakage has occurred on the output side of the power converter when the cycle of the voltage between the detection point and ground does not match the cycle of the output voltage of the AC generator. The leakage detection device according to claim 1, which is configured.   The leakage occurrence location determining means is that leakage has occurred in the circuit on the output side of the power converter when the period of the voltage between the detection point and the ground coincides with the period of the output voltage of the power converter. The leakage detection device according to claim 1, wherein the leakage detection device is configured to determine.   The leakage occurrence location determination means is a circuit between the AC generator and the power converter when the period of the voltage between the detection point and ground does not match the period of the output voltage of the power converter. The leakage detection device according to claim 1, wherein the leakage detection device is configured to determine that leakage has occurred.   The leakage occurrence location determination means determines that a leakage has occurred on the output side of the power converter when the cycle of the voltage between the detection point and the ground matches the cycle of the output voltage of the power converter, Determining that a leakage has occurred in the circuit between the AC generator and the power converter when the period of the voltage between the detection point and the ground does not coincide with the period of the output voltage of the power converter. The leakage detection device according to claim 1, which is configured. A leakage detecting device for an AC power supply device comprising: an AC generator; and a power converter that converts the output of the AC generator into an AC output having a constant frequency and supplies the AC converter to a load,
A detection point forming circuit for forming a detection point coupled to each output line of the AC generator through a high impedance element, a voltage detection circuit for detecting a voltage between the detection point and ground, and the voltage detection circuit outputting A leakage detection pulse generating circuit that compares the detection voltage with a reference voltage and generates a leakage detection pulse that indicates a different level between when the detection voltage is equal to or higher than the reference voltage and when the detection voltage is lower than the reference voltage; A leakage detection means for detecting that a leakage has occurred in the AC power supply device when it is detected that a detection voltage is equal to or higher than a reference voltage, and a leakage occurrence location for determining a leakage occurrence location from the cycle of the leakage detection pulse A leakage detection device for an AC power supply device comprising a determination unit. The reference voltage is set so that the leakage detection pulse is generated when leakage occurs between the AC generator and the power converter,
The leakage occurrence location determining means is configured to detect a leakage in a circuit between the AC generator and the power converter when it can be considered that the cycle of the leakage detection pulse matches the cycle of the output voltage of the AC generator. The leakage detection device according to claim 8, wherein the leakage detection device is configured to determine that it has occurred. The reference voltage is set so that the leakage detection pulse is generated when leakage occurs between the AC generator and the power converter,
The leakage occurrence location determination means determines that leakage has occurred on the output side of the power converter when it can be considered that the cycle of the leakage detection pulse does not match the cycle of the output voltage of the AC generator. The leakage detection device according to claim 8, which is configured. The reference voltage is set so that the leakage detection pulse is generated when leakage occurs between the AC generator and the power converter,
The leakage occurrence location determining means is configured to detect a leakage in a circuit between the AC generator and the power converter when it can be considered that the cycle of the leakage detection pulse matches the cycle of the output voltage of the AC generator. It is determined that a leakage has occurred on the output side of the power converter when it can be considered that the cycle of the leakage detection pulse does not match the cycle of the output voltage of the AC generator. The leakage detection device according to claim 8. The reference voltage is set so that the leakage detection pulse is generated when leakage occurs on the output side of the power converter,
The leakage occurrence location determination means determines that a leakage has occurred in a circuit on the output side of the power converter when it can be considered that the cycle of the leakage detection pulse matches the cycle of the output voltage of the power converter. The leakage detection device according to claim 8 configured as described above. The reference voltage is set so that the leakage detection pulse is generated when leakage occurs on the output side of the power converter,
The leakage occurrence location determination means is configured to detect a leakage in a circuit between the AC generator and the power converter when it can be considered that the cycle of the leakage detection pulse does not match the cycle of the output voltage of the power converter. The leakage detection device according to claim 8, wherein the leakage detection device is configured to determine that it has occurred. The reference voltage is set so that the leakage detection pulse is generated when leakage occurs on the output side of the power converter,
The leakage occurrence location determination means determines that a leakage has occurred on the output side of the power converter when it can be considered that the cycle of the leakage detection pulse matches the cycle of the output voltage of the power converter, It is configured to determine that a leakage has occurred in a circuit between the AC generator and the power converter when it can be considered that the period of the detection pulse does not match the period of the output voltage of the power converter. The electric leakage detection apparatus according to claim 8. A switch is inserted between the AC generator and the power converter,
The leakage occurrence location determination means is configured to determine that leakage has occurred on the AC generator side of the switch when the occurrence of leakage is detected by the leakage detection means in a state where the switch is open. The electric leakage detection device according to claim 8.   The AC generator is a three-phase AC generator, and the detection point forming circuit is composed of three resistors each having one end connected to the three-phase output line of the AC generator and the other end connected in common. The ground fault detection apparatus according to claim 1, wherein a common connection point of the three resistors is used as the detection point. The AC generator is a single-phase AC generator, and the detection point forming circuit is a resistance voltage dividing circuit connected between two output lines of the AC generator. The leakage detection device according to any one of claims 1 to 15, wherein a partial pressure point is used as the detection point.

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