JP3195809U - Inverter generator - Google Patents

Abstract

An inverter generator that suppresses a surge voltage suddenly generated during operation of an inverter and prevents the inverter from malfunctioning or causing breakdown due to dielectric breakdown is provided. A snubber circuit comprising a combination of a resistor R, a capacitor C and a diode D is connected in parallel with an inverter 20 of an inverter generator, and a surge voltage suddenly generated from the inverter 20 is absorbed by the snubber circuit and reduced. . Here, the capacitor C absorbs the surge voltage and suppresses the height of the protruding spike. The resistor R suppresses heat generation of the element due to the surge voltage. The reason why the forward end of the diode D is connected to the negative side via the capacitor C is that the negative side is the ground side, and therefore it is not necessary to actively suppress the surge voltage. [Selection] Figure 3

Description

  The present invention relates to an inverter generator, and more specifically, appropriately absorbs a surge voltage generated when an inverter built in the inverter generator converts a direct current into an alternating current. Therefore, it is possible to prevent the inverter from malfunctioning or being destroyed.

  Many forms of in-house power generation that obtains power independently from the power supply system of the power company are known. Regardless of the type of in-house power generation, if the load connected to the supplied power is a heating element such as an electric light or an electric heater, it is sufficient if the specified voltage and current are secured for the power, and the power frequency Variations in are generally not considered a problem.

  However, when the load connected to the supplied power is a rotating device such as a pulse motor, a fluorescent lamp or other personal computer, it is required that the power supply frequency does not vary and is stable. For example, since many of the recent motor rotation controls depend on the power supply frequency, the frequency needs to be accurate and unaltered. In response to this request, as a stationary private generator or portable generator, the converter converts the three-phase alternating current generated by the three-phase generator into direct current with a converter, and then converts this direct current into three-phase alternating current or single Inverter generators that convert to phase alternating current have been put into practical use. The inverter has a commutation control circuit that intermittently turns on and off direct current to turn it into alternating current, and the circuit performs on / off (switching) of the direct current at a predetermined cycle, so that alternating current at a desired frequency is generated. It is obtained. In order to obtain an accurate and stable frequency, pulse width modulation (PWM) control using a reference sine wave is generally used.

  The present invention relates to a circuit that absorbs a surge voltage that occurs instantaneously during operation of the inverter that constitutes the main part of the inverter generator. First, the basic configuration of the inverter generator will be described. In FIG. 1, reference numeral 10 indicates a three-phase generator having three armature windings U, V, and W arranged at a phase angle of 120 degrees. The three-phase generator 10 is driven by a rotation source (not shown) such as an engine to generate a three-phase alternating current.

  Three-phase alternating current from the three-phase generator 10 is input to a converter 14 provided with a rectifier such as a thyristor or triac, and is converted into direct current by the converter 14. The converted direct current is smoothed by the electrolytic capacitor 15 and then converted to a single-phase alternating current by the inverter 20 provided on the downstream side. The inverter 20 is composed of a self-extinguishing type switching element such as an IGBT (insulated gate bipolar transistor) or a power MOSFET, for example, and drives the gate to turn off and on (switching) the direct current. Convert to phase alternating current. The obtained single-phase alternating current is output to the U1 phase end and the V1 phase end via each sine wave output filter 30 connected in series to the inverter 20.

  The electric elements of the three-phase generator 10, the converter 14, and the inverter 20 are electrically controlled by various circuits built in the control unit 35. That is, the power supply circuit 41 in the control unit 35 is connected to the U phase and the O phase of the three-phase generator 10 to receive AC power supply, and after the voltage drop and DC exchange are performed in the power supply circuit 41, DC power is supplied to various circuits of the control unit 35. The DC voltage control circuit 37 controls the DC voltage when converted from AC to DC by the converter 14 within a certain range. The DC voltage control circuit 37 includes a resistor (DC voltage setting resistor) in the substrate for setting the DC voltage converted by the converter 14 to a desired value.

  The gate of the self-extinguishing switching element built in the inverter 20 is driven by an inverter drive circuit 22. For example, the inverter drive circuit 22 includes a pulse width modulation (PWM) circuit, and receives an input of a composite signal in which a sine wave of a reference frequency made from a data signal for a sine wave and a carrier wave (triangular wave) are superimposed, Here, the pulse width-modulated pulse opens and closes the gate of the self-extinguishing type switching element to perform commutation control. In FIG. 1, a reference sine wave signal circuit 26 generates a data signal necessary to generate a sine wave having a desired frequency as a reference. A data signal for creating a sine wave from the reference sine wave signal circuit 26 is input to a sine wave conversion circuit 24 connected to the circuit 26. The sine wave conversion circuit 24 generates a desired reference sine wave using the data signal. The reference sine wave is output-compared with a carrier wave (triangular wave set at a higher frequency than the reference sine wave) generated by the carrier wave generation circuit 31 to form a superimposed synthesized signal, and the synthesized signal Is input to the inverter drive circuit 22. In the reference sine wave signal circuit 26, a resistor (reference sine wave voltage setting resistor) for setting a voltage for setting the reference sine wave to a desired value is provided in the substrate, and this resistor serves as a module. Exchange is possible. Reference numeral 39 denotes a voltage feedback circuit. The voltage feedback circuit 39 detects a single-phase AC voltage output to the U1 phase end and the V1 phase end, and feeds back the detected value to the inverter drive circuit 22. To do.

  The three-phase generator 10 in FIG. 1 includes single armature windings U, V, and W, and finally outputs a single-phase alternating current. On the other hand, the three-phase generator 10 of the inverter generator shown in FIG. 2 has a master armature winding 10a and a slave armature winding 10b, and finally outputs a three-phase alternating current. The other basic configuration is the same as that of the inverter generator of FIG. However, the converter includes a first converter 16 that converts the three-phase alternating current generated by the master winding 10a into direct current, and a second converter 18 that converts the three-phase alternating current generated by the slave winding 10b into direct current. Is done. Each direct current from the first and second converters 16 and 18 is converted into a single-phase alternating current in the inverter 20. The obtained single-phase alternating current is output to the U1-phase end, the V1-phase end, and the W1-phase end via each sine wave output filter 30.

  The inverter generator of FIG. 2 has U1, V1 and W1 phase output ends, but the AC output is not single phase but single phase. That is, the alternating current output from the inverter 20 is single-phase, and this single-phase alternating current is output to the U1 phase end and the V1 phase end. Therefore, the W1 phase end shown in FIG. This is because the self-extinguishing type switching element incorporated in the inverter 20 is only for two phases, and the gate control of the switching element by the inverter drive circuit 22 is performed only for the two phases. 2 is the same as the configuration of the inverter generator shown in FIG. 1 in that the power supply circuit 41, the DC voltage control circuit 37, and the voltage feedback circuit 39 are built in the control unit 35. It is.

JP 2008-2370099 A

  The inverter generator shown in FIGS. 1 and 2 converts the three-phase alternating current generated by the three-phase alternating current generator driven by a rotation source such as an engine into direct current with a converter, and then converts the direct current into alternating current with the inverter. In addition, by performing appropriate electrical control to the inverter and the converter with the control unit, it is extremely excellent in that a single-phase alternating current with an accurate and stable frequency can be obtained.

  However, in the inverter generator shown in FIGS. 1 and 2, a large surge voltage is often suddenly generated in the inverter 20 during its operation. The surge voltage instantaneously occurs as a spike on both the positive side and the negative side of the AC waveform with respect to the AC converted by the inverter 20. If the value of the surge voltage is particularly high on the positive side or is frequently generated, the inverter 20 may malfunction, and the inverter 20 may be damaged. Therefore, it is conceivable to use a inverter having a large withstand voltage capacity so that the inverter 20 does not malfunction or break down even if a high surge voltage occurs. However, those with a large withstand voltage capacity have a drawback that the unit price increases and the dimensions become large.

  The present invention has been proposed in order to solve the above-described drawback of the malfunction of the inverter due to the surge voltage, and suddenly occurs in the inverter by connecting a snubber circuit in parallel to the inverter of the inverter generator. The surge voltage is absorbed by the snubber circuit.

  In order to overcome the above problems and achieve an intended object, an inverter generator according to claim 1 of the present application is a three-phase generator driven by a rotation source to generate a three-phase alternating current, and the three-phase generator. An inverter generator comprising a converter that converts three-phase alternating current generated by DC into direct current, an inverter that converts direct current from the converter into single-phase alternating current, and a control unit that electrically controls the three-phase generator, the converter and the inverter In the present invention, a snubber circuit including a capacitor, a resistor, and a diode is connected in parallel with the inverter.

  Similarly, in order to overcome the above-mentioned problem and achieve the intended purpose, in the inverter generator according to claim 2 of the present application, the snubber circuit connects the resistor and the diode in parallel and forwards the diode. One end of the capacitor is connected in series to the end, the reverse end of the diode is connected to the plus side of the inverter, and the other end of the capacitor is connected to the minus side of the inverter. This is the gist.

Furthermore, in order to overcome the above-mentioned problems and achieve the intended purpose, in the inverter generator according to claim 3 of the present application, the snubber circuit is provided in the vicinity of the inverter, and the resistor constituting the snubber circuit is provided. The gist is that the lead wire is extended to improve the cooling efficiency.
According to the above claims 1 to 3, the snubber circuit connected in parallel to the inverter absorbs the surge voltage generated during operation of the inverter that converts direct current to alternating current. Never come. Further, since the surge voltage appears as a pulsed spike (peak voltage) having a large amplitude, absorption of the surge voltage contributes to reduction of electrical noise.

  According to the inverter generator according to the present invention, the surge voltage generated from the inverter is absorbed and reduced by the snubber circuit connected in parallel to the inverter. For this reason, there is no malfunction or damage to the inverter. Moreover, although the surge voltage appears as a pulsed spike, the noise is suppressed from being released by absorbing this surge voltage.

It is a whole circuit diagram of the inverter generator which outputs the single phase alternating current by which this invention is implemented. It is a whole circuit diagram of the inverter generator which outputs the alternating current of the single phase three wire in which this invention is implemented. 3 is an enlarged view of a snubber circuit connected in parallel to the inverter in the circuit of the inverter generator of FIGS. 1 and 2. FIG.

  The present invention can absorb a pulsed surge voltage suddenly generated by an inverter when a direct current obtained by converting a three-phase alternating current with a converter is converted into a single-phase alternating current with an inverter (switching element) in a control unit of the inverter generator. A snubber circuit is provided. Since the inverter generator and the control unit in which this device is implemented are as described in FIGS. 1 and 2, the description of the above-described configuration is omitted, and a configuration in which a snubber circuit is connected in parallel to the inverter. Only will be described. This description corresponds to both the single-phase two-wire system in FIG. 1 and the single-phase three-wire system in FIG.

  In the circuit diagram of the inverter generator shown in FIGS. 1 and 2, a snubber circuit 42 shown in FIG. 3 is connected to the inverter 20 in parallel. That is, the inverter 20 in FIG. 1 is connected to the upstream converter 16 by two connections 20a and 20b, where the polarity of the connection 20a is positive and the polarity of the connection 20b is negative. It is. Further, the inverter 20 shown in FIG. 2 is connected to the first converter 16 and the second converter 18 on the upstream side by two connections 20a and 20b. As for the polarity of the connection shown in FIG. 2, the connection 20a is positive, and the connection 20b is negative.

  Here, the snubber circuit is a circuit that absorbs and suppresses a pulsed voltage (called a surge voltage) that instantaneously exceeds a steady state in a current flowing through a specific electric circuit. That is. The inverter is a so-called switching element, and is a circuit element that converts an input direct current into an alternating current by performing an off (closed) and on (open) switching operation at a predetermined cycle. As described above, the inverter performs a switching operation for turning on / off the direct current, so that the surge voltage having a transient pulse characteristic is generated when the switch is cut off (off). Therefore, the present invention contemplates that the surge voltage suddenly generated during the switching operation of the inverter is absorbed and suppressed by the snubber circuit.

  In the present invention, the snubber circuit 42 is connected in parallel with the inverter 20 of the inverter generator. The contents of the snubber circuit 42 and the connection polarity to the inverter 20 are as shown in FIG. That is, the snubber circuit 42 is composed of a combination of a resistor R, a capacitor C and a diode D, and connects the resistor R and the diode D in parallel as shown in FIG. It is comprised by connecting one end of the said capacitor | condenser C to a part in series. The reverse end of the diode D is connected to the plus side of the inverter 20, and the other end of the capacitor C is connected to the minus side of the inverter 20.

  Here, the capacitor C absorbs the surge voltage and suppresses the height of the spike from which the surge voltage protrudes. The resistor R suppresses heat generation of the element due to a surge voltage. Further, the diode D is connected in parallel with the resistor R, and the forward end of the diode D is connected to the negative side of the inverter 20 via the capacitor C, so that the positive side of the connection 20a Thus, current flows only to the minus side of the connection 20b. Thereby, the surge voltage generated on the plus side can be absorbed by the capacitor C, and the surge voltage can be suppressed low. Since the negative side of the connection 20b is the ground side, there is little need to positively suppress the surge voltage.

  When the snubber circuit 42 is connected in parallel to the inverter 20, for example, the diode D and the capacitor C in the snubber circuit 42 are installed in the vicinity of the IGBT element constituting the inverter 20, and the resistor R It is preferable to promote the heat radiation cooling of the resistor R by extending the wire as long as possible. Further, since the snubber circuit 42 generates heat as the surge voltage is absorbed, it is recommended that the snubber circuit 42 be installed at a location where cooling air flows well in the inverter generator housing.

10 three-phase generator, 14 converter, 20 inverter, 35 control unit,
42 Snubber circuit, C capacitor, D diode, R resistance

Claims (3)

A three-phase generator (10) driven by a rotation source to generate a three-phase alternating current, a converter (14) for converting the three-phase alternating current generated by the three-phase generator (10) into a direct current, and the converter (14 Inverter generator comprising an inverter (20) that converts direct current from a single-phase alternating current into a single-phase alternating current, and a control unit (35) that electrically controls these three-phase generator (10), converter (14), and inverter (20) In
An inverter generator comprising a snubber circuit (42) comprising a capacitor (C), a resistor (R), and a diode (D) in parallel with the inverter (20).   The snubber circuit (42) connects the resistor (R) and the diode (D) in parallel, and connects one end of the capacitor (C) in series to the forward end of the diode (D). The reverse end of the diode (D) is connected to the positive side of the inverter (20), and the other end of the capacitor (C) is connected to the negative side of the inverter (20). The inverter generator according to claim 1.   The snubber circuit (42) is provided close to the inverter (20), and the lead wire of the resistor (R) constituting the snubber circuit (42) is extended to improve cooling efficiency. The inverter generator according to claim 2.

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