JP2002247895A - Power output device, abnormality detection device therefor, and abnormality detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more precisely adjust a neutral current applied to a neutral of a motor. SOLUTION: Neutral currents Ion and Ion-1 applied to a neutral of a motor are calculated from respective phase currents Iu, Iv, and Iw of the motor which are detected at two adjacent points whose phases are shifted from a peak or a valley of a carrier wave (triangular wave) by 90 degrees (S102). The neutral currents Ion and Ion-1 are averaged to calculate an average value Ioave of the neutral currents (S104) and, ONs/OFFs of a switching device of an inverter circuit are controlled according to the average value and a neutral current is controlled so as to make a required neutral current applied to the neutral of the motor (S106). As the neutral current fluctuates with a phase advancing by 90 degrees from the peak or the valley of the carrier wave, the neutral currents Ion and Ion-1 mean the upper limit value and lower limit value of the neutral current. By averaging the neutral currents Ion and Ion-1, the average value Ioave can be more precisely calculated and the neutral current can be more accurately adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power output device and a device and method for detecting an abnormality thereof.

[0002]

2. Description of the Related Art As a conventional power output device, there has been proposed a power output device having a DC power supply connected to a positive or negative bus of an inverter circuit for applying a three-phase alternating current to a motor and a neutral point of the motor. (For example, see Japanese Patent Application Laid-Open No. 10-337
047 and JP-A-11-178114). In this device, in order to suppress the occurrence of torque pulsation of the motor, a DC component current is usually applied to the winding of the motor, that is,
The switching control of the switching element of the inverter circuit is performed so that the neutral point current of the DC component does not flow to the neutral point of the motor. As a method of adjusting the neutral point current,
The current value of the neutral point current flowing to the neutral point of the motor is detected at the peak or valley point of the triangular wave that is the carrier wave, and the detected neutral point current is compared with the neutral point current command value. There is a type in which switching of a switching element of an inverter circuit is controlled by feedback. this is,
Since the neutral point current oscillates at the same frequency as the carrier and 90 degrees ahead of the phase, the current value of the neutral point current detected at the peak or valley point of the carrier is the average of the neutral point current ripple. Values based on the fact that they can be considered as the DC component of the neutral point current.

[0003]

However, in such a power output device, since the neutral point current is detected only at the peak or valley point of the carrier, it is detected that the point at which the neutral point current is detected is slightly deviated. In some cases, a large error occurs in the average value of the neutral point current, and the neutral point current cannot be adjusted properly. Further, in the conventional power output device, the average of the neutral point current can be obtained, but the amplitude of the neutral point current cannot be obtained. Therefore, abnormality of the power output device based on the amplitude of the neutral point current, for example,
In order to reduce the ripple of the neutral point current, it is not possible to detect the abnormality of the reactor attached between the neutral point of the electric motor and the DC power supply.

An object of the power output apparatus of the present invention is to adjust the neutral point power more accurately.

Another object of the present invention is to detect an abnormality in a power output device based on a neutral point current.

Another object of the power output method of the present invention is to provide a method for more accurately adjusting the neutral point power.

Another object of the present invention is to provide a method for detecting an abnormality in a power output device based on a neutral point current.

[0008]

SUMMARY OF THE INVENTION The power output apparatus and the abnormality detection apparatus and method of the present invention are
The following measures were taken in order to achieve at least a part of the above objects.

In the first power output device of the present invention, a motor that is rotationally driven by polyphase AC, an inverter circuit that can supply polyphase AC power to the motor by switching a plurality of switching elements, A first power supply connected to the positive electrode bus and the negative electrode bus, a second power supply connected to one of the positive electrode bus and the negative electrode bus of the inverter circuit, and a neutral point of the electric motor, Neutral point power transmitted and received via the neutral point is at least 2 in a rising section or a falling section of the neutral point power.
The gist of the present invention is to include a neutral point power detecting means for detecting at a single point, and a control means for performing switching control of a switching element of the inverter circuit based on the detected neutral point power.

In the first power output device of the present invention, the neutral point power detecting means converts the neutral point power transmitted / received through the neutral point of the motor into the rising section of the neutral point power or falling. Detection is performed at at least two points in the section, and the control means performs switching control of the switching element of the inverter circuit based on the detected neutral point power. This neutral point power detecting means shall be a neutral point current detecting means for detecting a neutral point current flowing to the neutral point of the electric motor, and the neutral point current shall be a half cycle around the peak or valley of the carrier wave. If the neutral point current oscillates at the same frequency as that of the carrier wave and the phase is advanced by 90 degrees, the degree of rise or fall of the ripple of the neutral point current is assumed. Can be calculated. Therefore, if switching control of the switching element of the inverter circuit is performed based on the detected neutral point current, the switching element of the inverter circuit is more controlled than the one using the neutral point current detected only at the peak or valley point of the carrier wave. The neutral point current flowing to the neutral point of the motor can be adjusted accurately.

[0011] A second power output device of the present invention is a motor that is driven to rotate by polyphase alternating current, an inverter circuit that can supply polyphase alternating current power to the motor by switching a plurality of switching elements, A first power supply connected to one of the positive bus and the negative bus and a neutral point of the motor; and a second bus different from the one bus of the inverter circuit and a neutral point of the motor. A second power source connected thereto, and neutral point power for detecting neutral point power transmitted and received via a neutral point of the electric motor at at least two points in a rising section or a falling section of the neutral point power. The gist of the present invention is to include a detection unit and a control unit that performs switching control of a switching element of the inverter circuit based on the detected neutral point power.

In the second power output apparatus according to the present invention, the neutral point power detecting means converts the neutral point power transmitted / received through the neutral point of the electric motor into a rising section of the neutral point power or falling. Detection is performed at at least two points in the section, and the control means performs switching control of the switching element of the inverter circuit based on the detected neutral point power. This neutral point power detecting means shall be a neutral point current detecting means for detecting a neutral point current flowing to the neutral point of the electric motor, and the neutral point current shall be a half cycle around the peak or valley of the carrier wave. If the neutral point current oscillates at the same frequency as that of the carrier wave and the phase is advanced by 90 degrees, the degree of rise or fall of the ripple of the neutral point current is assumed. Can be calculated. Therefore, if switching control of the switching element of the inverter circuit is performed based on the detected neutral point current, the switching element of the inverter circuit is more controlled than the one using the neutral point current detected only at the peak or valley point of the carrier wave. The neutral point current flowing to the neutral point of the motor can be adjusted accurately.

In the first and second power output devices of the present invention, the neutral point power detecting means is means for detecting at two points which are 90 degrees out of phase with respect to the peak or valley of the carrier. It can also be. With this configuration, the upper limit value and the lower limit value of the neutral point current are detected, and the neutral point current flowing to the neutral point of the electric motor can be adjusted more accurately using the detection results.

In the first and second power output devices according to the present invention having a neutral point current detecting means, the neutral point current is detected based on the neutral point current detected by the neutral point current detecting means. The amplitude may be calculated.

Further, in the first and second power output devices according to the present invention having a neutral point current detecting means, the neutral point current is detected based on the neutral point current detected by the neutral point current detecting means. An average calculating means for calculating an average of the current;
The control means may be means for performing switching control of a switching element of the inverter circuit based on the average of the calculated neutral point currents.

A first abnormality detecting device of the present invention is an abnormality detecting device for detecting an abnormality of the first and second power output devices of the present invention in a mode including a neutral point current detecting means. The gist of the present invention is to include an abnormality detection unit that detects an abnormality of the power output device based on the neutral point current detected by the neutral point current detection unit.

In the first abnormality detecting device of the present invention, the abnormality detecting means detects an abnormality of the power output device based on a neutral point current flowing to a neutral point of the electric motor. Since the neutral point current fluctuates due to an abnormality in the power output device, for example, a reactor or a DC power supply, an abnormality in the power output device can be detected by monitoring the neutral point current.

According to a second abnormality detecting device of the present invention,
An abnormality detecting device for detecting an abnormality of the first and second power output devices according to the aspect of the present invention, comprising an reactor for connecting a power supply and a neutral point of the electric motor, and comprising an amplitude calculator. The gist of the present invention is to provide an abnormality detecting means for detecting an abnormality of the reactor based on the amplitude of the neutral point current calculated by the means.

In the second abnormality detecting device of the present invention, the abnormality of the reactor is detected based on the amplitude of the neutral point current flowing to the neutral point of the motor. Normally, if a reactor is connected between the second power supply and the neutral point of the motor, the amplitude of the neutral point current is reduced. Therefore, it is possible to detect the reactor abnormality by monitoring the amplitude of the neutral point current. it can.

According to a first power output method of the present invention, there is provided a motor driven to rotate by a polyphase AC, an inverter circuit capable of supplying a polyphase AC power to the motor by switching a plurality of switching elements, and an inverter circuit for the inverter circuit. A power supply comprising: a first power supply connected to a positive electrode bus and a negative electrode bus; and a second power supply connected to one of the positive electrode bus and the negative electrode bus of the inverter circuit and a neutral point of the electric motor. A power output method in an output device, comprising detecting neutral point power transmitted and received via a neutral point of the electric motor at at least two points in a rising section or a falling section of the neutral point power, The gist is to perform switching control of the switching element of the inverter circuit based on the detected neutral point power.

In the first power output method of the present invention, the neutral point power transmitted / received via the neutral point of the motor is converted into at least two points in the rising section or the falling section of the neutral point power. It detects and controls the switching of the switching element of the inverter circuit based on the detected neutral point power. The neutral point power shall be a neutral point current flowing to the neutral point of the motor, and the neutral point current shall be detected at at least two points within a half cycle around the peak or valley of the carrier. Then, the neutral point current oscillates at the same frequency as that of the carrier wave and advanced by 90 degrees in phase, so that the degree of rise or fall of the ripple of the neutral point current can be calculated. Therefore, if switching control of the switching element of the inverter circuit is performed based on the detected neutral point current, the switching element of the inverter circuit is more controlled than the one using the neutral point current detected only at the peak or valley point of the carrier wave. The neutral point current flowing to the neutral point of the motor can be adjusted accurately.

According to a second power output method of the present invention, there is provided a motor which is driven to rotate by a polyphase alternating current, an inverter circuit capable of supplying polyphase alternating current power to the motor by switching a plurality of switching elements, A first power supply connected to one of the positive bus and the negative bus and a neutral point of the motor; and a second bus different from the one bus of the inverter circuit and a neutral point of the motor. A second power source connected to the power output device, wherein the neutral point power transmitted and received via the neutral point of the electric motor is generated in a rising section or a falling section of the neutral point power. And that the switching element of the inverter circuit is subjected to switching control based on the detected neutral point power.

In the second power output method of the present invention, the neutral point power transmitted and received via the neutral point of the motor is converted into at least two points in the rising section or the falling section of the neutral point power. It detects and controls the switching of the switching element of the inverter circuit based on the detected neutral point power. The neutral point power shall be a neutral point current flowing to the neutral point of the motor, and the neutral point current shall be detected at at least two points within a half cycle around the peak or valley of the carrier. Then, the neutral point current oscillates at the same frequency as that of the carrier wave and advanced by 90 degrees in phase, so that the degree of rise or fall of the ripple of the neutral point current can be calculated. Therefore, if switching control of the switching element of the inverter circuit is performed based on the detected neutral point current, the switching element of the inverter circuit is more controlled than the one using the neutral point current detected only at the peak or valley point of the carrier wave. The neutral point current flowing to the neutral point of the motor can be adjusted accurately.

In the first and second power output methods of the present invention, the at least two points may be two points that are 90 degrees out of phase with respect to a carrier peak or valley. . In this case, the upper limit value and the lower limit value of the neutral point current are detected, so that the neutral point current flowing to the neutral point of the electric motor can be more accurately adjusted using the detection results.

A first abnormality detecting method according to the present invention is an abnormality detecting method for detecting an abnormality in the first and second power output devices according to the aspect of the present invention, comprising a neutral point current detecting means. The gist is to detect abnormality of the power output device based on the neutral point current detected by the neutral point power detection means.

In the first abnormality detecting method of the present invention, the abnormality of the power output device is detected based on the neutral point current flowing to the neutral point of the electric motor. Since the neutral point current fluctuates due to an abnormality in the power output device, for example, a reactor or a DC power supply, an abnormality in the power output device can be detected by monitoring the neutral point current.

The second abnormality detecting method according to the present invention is characterized in that
An abnormality detecting device for detecting an abnormality of the first and second power output devices according to the aspect of the present invention, comprising an reactor for connecting a power supply and a neutral point of the electric motor, and comprising an amplitude calculator. The gist is to detect abnormality of the reactor based on the amplitude of the neutral point current calculated by the means.

In the second abnormality detection method of the present invention, the abnormality of the reactor is detected based on the amplitude of the neutral point current flowing to the neutral point of the motor. Normally, if a reactor is connected between the second power supply and the neutral point of the motor, the amplitude of the neutral point current is reduced. Therefore, it is possible to detect the reactor abnormality by monitoring the amplitude of the neutral point current. it can.

[0029]

Next, embodiments of the present invention will be described with reference to examples. FIG. 1 is a configuration diagram schematically showing the configuration of a power output device 20 according to one embodiment of the present invention. As shown, the power output device 20 of the embodiment includes a motor 22 that is rotationally driven by three-phase AC, an inverter circuit 24 that can convert DC power into three-phase AC power and supply the three-phase AC power to the motor 22, and an inverter circuit 24. A first DC power supply 30 connected to the positive bus 26 and the negative bus 28 of the inverter circuit; a second DC power supply 32 connected to the negative bus 28 of the inverter circuit 24 and the neutral point of the motor 22; U of phase coil
current sensors 52 to 5 for detecting a current flowing in each phase of vw
6, a current sensor 58 for detecting a current flowing through the neutral point of the motor 22, a neutral point of the motor 22 and the second DC power supply 32.
And an electronic control unit 40 for controlling the entire apparatus.

The motor 22 is configured as, for example, a synchronous generator motor capable of generating electricity, comprising a rotor having a permanent magnet attached to the outer surface thereof and a stator having a three-phase coil wound thereon. The rotating shaft of the motor 22 is the output shaft of the power output device 20 according to the embodiment, and power is output from the rotating shaft. Since the motor 22 is configured as a generator motor, power can be generated by the motor 22 by inputting power to the rotating shaft of the motor 22.

The inverter circuit 24 comprises six transistors T1 to T6 and six diodes D1 to D6. The six transistors T <b> 1 to T <b> 6 are arranged in pairs each of which is on the source side and the sink side with respect to the positive electrode bus 26 and the negative electrode bus 28, respectively. It is connected.

The first DC power supply 30 and the second DC power supply 32
For example, it is configured as a nickel-metal hydride or lithium ion-based secondary battery, and the voltage between the terminals of the first DC power supply 30 is adjusted to be about twice the voltage between the terminals of the second DC power supply 32. .

The electronic control unit 40 is configured as a microprocessor mainly including a CPU 42, and includes a ROM 44 storing a processing program, a RAM 46 temporarily storing data, and an input / output port (not shown). Prepare. The electronic control unit 40 includes a current of each phase (uvw) of the motor 22 from the current sensors 52 to 56, a neutral point current from the current sensor 58, and a rotation angle sensor 60 for detecting the rotation angle of the rotor of the motor 22. , A command value relating to the operation of the motor 22 and the like are input via an input port. Further, a control signal for performing switching control of the transistors T1 to T6 of the inverter circuit 24 is output from the electronic control unit 40 via an output port. The drive control of the motor 22 in the electronic control unit 40 is performed, for example, based on the torque command value of the motor 22 and the rotation speed calculated based on the rotation angle of the rotor from the rotation angle sensor 60. A sine wave is set as a voltage command value to be applied to the coil, and a PWM signal generated by comparing the set sine wave with a carrier (for example, a triangular wave) is output to the transistors T1 to T6 of the inverter circuit 24. It is done by doing. At this time, the neutral point current flowing to the neutral point of the motor 22 can be adjusted by, for example, offsetting a sine wave as a voltage command value to the plus side or the minus side with respect to the carrier. The amount of the offset is set based on, for example, the neutral point current command value and the neutral point current value detected by the current sensor 58.

Next, the operation of the power output apparatus 20 of the embodiment constructed as described above, in particular, the neutral point current flowing to the neutral point of the motor 22 is detected, and the neutral point current flowing to this neutral point is adjusted. The operation at that time will be described. FIG. 2 is a flowchart illustrating an example of a neutral point current control processing routine executed by the electronic control unit 40 of the power output device 20. This routine is repeatedly executed in a cycle for each point having a phase shift of 90 degrees from a peak or a valley of a carrier wave (such as a triangular wave).

When the neutral point current control processing routine is executed, the CPU 42 of the control device 40
The current I of each phase of the motor 22 detected by 2 to 56
u, Iv, and Iw are read (step S100), the read currents Iu, Iv, and Iw are added, and the neutral point current Ion (Ion = Ion) flowing to the neutral point of the motor 22 at this time is added.
u + Iv + Iw) is calculated (step S102). FIG. 3 is an explanatory diagram showing the relationship between the carrier wave and the neutral point current flowing to the neutral point of the motor 22. As shown in FIG.
The neutral point current flowing through the neutral point 2 oscillates at the same frequency as that of the carrier wave and with a phase advanced by 90 degrees from the peak or valley. The neutral point current Ion calculated from the currents Iu, Iv, Iw of the respective phases detected at the above indicates an upper limit value or a lower limit value. In the embodiment, the neutral point current Ion flowing to the neutral point is calculated from the currents Iu, Iv, Iw of each phase of the motor 22. However, the neutral point current flowing from the current sensor 58 directly to the neutral point is calculated. The current Ion may be detected, or both may be averaged to calculate the neutral point current Ion.

When the neutral point current Ion is calculated in this manner, the calculated neutral point current Ion and the neutral point current Ion-1 calculated in the previous routine are averaged to obtain the neutral point current Ion. Average Ioave (Ioave = (Io
(n + Ion-1) / 2) (Step S10)
4). Then, the average Ioa of the calculated neutral point current is calculated.
The transistors T1 to T6 of the inverter circuit 24 are set so that a desired neutral point current flows to the neutral point of the motor 22 based on the ve (or so that a DC component current does not flow to the neutral point of the motor 22). The PWM signal is output to control the neutral point current (step S106), and this routine ends.

Subsequently, the power output device 2 of this embodiment
An abnormality detection device that detects an abnormality of 0, for example, an abnormality of the reactor 38 will be described. The abnormality detection device includes the current sensors 52 to 58 in the power output device 20 and the electronic control unit 40. From the electronic control unit 40, an L for outputting an abnormality of the reactor 38 is provided.
The lighting signal to the ED 70 is output via the output port. Note that the abnormality detection device may be configured separately from the power output device 20. FIG. 4 is a flowchart illustrating an example of a reactor abnormality determination processing routine executed by the CPU 42 of the electronic control unit 40. This routine is repeatedly executed in a cycle for each point having a phase shift of 90 degrees around a peak or a valley of a carrier wave (such as a triangular wave) as in the routine of FIG.

When the reactor abnormality determination routine is executed, the CPU 42 of the electronic control unit 40 first determines each phase of the motor 22 detected by the current sensors 52 to 56 as in S100 and S102 of the routine of FIG. Of the currents Iu, Iv, and Iw (step S20)
0), the read currents Iu, Iv, Iw are added, and the neutral point current Io flowing to the neutral point of the motor 22 at this time is added.
n (Ion = Iu + Iv + Iw) is calculated (step S202). Subsequently, the calculated neutral point current Ion
And the neutral point current Ion-1 calculated in the previous routine is calculated, and the absolute value is calculated as the neutral point current amplitude IA (I
A = | Ion−Ion−1 |) is calculated (step S204). As described above, the neutral point current Ion indicates the upper limit or the lower limit of the current flowing to the neutral point, and the neutral point current Io calculated in the previous routine.
Since n-1 indicates the lower limit or upper limit opposite to the neutral point current Ion, the neutral point current Ion (upper limit or lower limit) and the neutral point current Ion calculated in the previous routine are used.
By taking the absolute value of the difference from -1 (lower limit or upper limit), the amplitude IA of the neutral point current can be calculated.

When the amplitude IA of the neutral point current is calculated, it is determined whether the calculated amplitude IA is equal to or smaller than a threshold value IAref (step S206). Where the threshold IAref
Is a threshold value for determining whether or not the reactor 38 provided between the neutral point of the motor 22 and the second DC power supply 32 has an abnormality (for example, a short circuit). That is,
The reactor 38 is provided to reduce the ripple of the neutral point current (reduce the amplitude IA). However, when the reactor 38 is not reduced so much, it is determined that the reactor 38 is abnormal. As a result of the determination, when it is determined that the amplitude IA is equal to or smaller than the threshold value IAref, it is determined that the reactor 38 has sufficiently performed the function of reducing the current ripple and is normal (Step S).
208) This routine ends. On the other hand, if it is determined that amplitude IA exceeds threshold value IAref, it is determined that an abnormality such as a short circuit has occurred in reactor 38, the abnormality is output (step S210), and this routine ends. The output of the reactor abnormality is performed, for example, by outputting a lighting signal to the LED 70.

According to the power output device 20 of the embodiment described above, the phase is shifted by 90 degrees from the peak or valley of the carrier wave.
Current Ion, Ion-1 at two points
Since the neutral point current is controlled using the average Ioave of the neutral point current calculated from (the upper limit value and the lower limit value of the neutral point current), the neutral point current is directly calculated at the peak or valley point of the carrier wave. The average of the neutral point current can be derived more accurately than the one that detects the average value of, and the neutral point current can be more appropriately controlled based on this.

Further, according to the abnormality detection device of the power output device 20 of the embodiment, the neutral point currents Ion and Io at two points 90 degrees out of phase from the peak or valley of the carrier wave.
The amplitude IA of the neutral point current can be calculated on the basis of n-1 (the upper limit value and the lower limit value of the neutral point current). It is possible to determine the abnormality of the reactor 38 attached between the power point and the DC power supply 32.

In the power output device 20 of the embodiment, the average Ioave of the neutral point current is calculated based on the neutral point currents detected by the current sensors 52 to 56 and the current sensor 58. The amplitude IA of the current may be calculated.

Although the abnormality detecting device of the power output device 20 of the embodiment detects the abnormality of the reactor 38 based on the amplitude IA of the neutral point current, the neutral point current flowing through the neutral point of the motor 22 is used. The abnormality of the power output device 20 such as the DC power supply 32 other than the reactor 38 may be detected based on the average of the neutral point current or the degree of increase or decrease of the neutral point current. This is based on the fact that when an abnormality occurs in the power output device 20, the neutral point current flowing to the neutral point of the motor 22 fluctuates accordingly.

In the power output device 20 and the abnormality detection device according to the embodiment, the amplitude of the neutral point current is determined based on the two neutral point current values detected at the points 90 degrees out of phase from the peaks and valleys of the carrier wave. Although the IA and the average Ioave are calculated, two or more points within a half cycle around the peak or valley of the carrier wave, that is, while the neutral point current is rising or falling, Based on the neutral point current values detected at two or more points, the neutral point current amplitude IA and average I
Oave may be calculated. As described above, the neutral point current oscillates at the same frequency as that of the carrier wave and with a phase advance of 90 degrees. Therefore, the neutral point current is generated at two or more points within a half cycle around the peak or valley of the carrier wave. By detecting the current, the degree of rise or fall of the neutral point current can be calculated. Therefore, the upper limit value and the lower limit value of the neutral point current can be calculated based on the calculated degree of rise or fall and the neutral point current phase information at the point where the neutral point current is detected. Thus, the neutral point current amplitude IA and the neutral point current average Io
ave can be calculated.

In the power output device 20 of the embodiment, the first DC power supply 30 for connecting the positive bus 26 and the negative bus 28 of the inverter circuit 24 is provided, but a capacitor is provided instead of the first DC power 30. It may be a thing.
In this case, the transistors T1 to T of the inverter circuit 24
6 and the coil of each phase of the motor 22 can be regarded as a boost chopper circuit that boosts the voltage of the second DC power supply 32 and stores the boosted chopper in a capacitor. Therefore, the stored capacitor can be regarded as a DC power supply. The same processing as that of the power output device 20 and the abnormality detection device of the embodiment can be performed. Further, in the power output device 20 of the embodiment, the second DC power supply 32 is attached so as to connect the negative bus 28 of the inverter circuit 24 and the neutral point of the motor 22, but the positive bus 26 of the inverter circuit 24 and the motor 22 are connected. The second DC power supply may be attached so as to connect to the neutral point.

In the power output device 20 of the embodiment, the first DC power supply 30 is attached so that the positive bus 26 and the negative bus 28 of the inverter circuit 24 are connected.
The first DC power supply 30B may be attached so as to connect the positive bus 26 of the inverter circuit 24 and the neutral point of the motor 22 as in a power output device 20B of a modified example illustrated in FIG. At this time, the power output device of the embodiment in which a DC power supply having a voltage equal to the sum of the voltage of the first DC power supply 30 </ b> B and the voltage of the second DC power supply 32 is connected to the positive bus 26 and the negative bus 28 of the inverter circuit 24. The first DC power supply 30 can be regarded as the first DC power supply 20, and the same processing as that of the power output device 20 and the abnormality detection device of the embodiment can be performed. That is, the average Ioave of the neutral point current is calculated and the neutral point current can be adjusted based on the average Ioave. The amplitude IA of the neutral point current is calculated, and the first DC current is calculated based on the amplitude IA. An abnormality of power output device 20B such as reactor 38B connected between the connection point between power supply 30B and second DC power supply 32 and the neutral point of motor 22 can be detected. In the power output device 20B of this modification, the first DC power supply 30
A capacitor may be provided instead of B. In this case, the transistors T1 to T6 of the inverter circuit 24
And a circuit composed of coils of each phase of the motor 22 can be regarded as a chopper circuit that stores the voltage of the second DC power supply 32 in a capacitor. The same processing as that of the abnormality detection device 20B or its abnormality detection device can be performed. In the power output device 20 </ b> B of the modified example, a capacitor may be provided instead of the second DC power supply 32.

In the power output device 20 of the embodiment, the power output device 20B of the modified example, and the modified example, a synchronous generator motor driven by three-phase AC is used as the motor 22, but any type of motor driven by polyphase AC is used. An electric motor may be used.

The embodiments of the present invention have been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various embodiments may be made without departing from the gist of the present invention. Of course, it can be carried out.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing the configuration of a power output device 20 according to one embodiment of the present invention.

FIG. 2 is a flowchart illustrating an example of a neutral point current control processing routine executed by an electronic control unit 40 of the power output device 20 according to the embodiment.

FIG. 3 is a diagram showing a relationship between a carrier wave and a neutral point current flowing to a neutral point of a motor 22.

FIG. 4 is an electronic control unit 4 of the abnormality detection device according to the embodiment.
9 is a flowchart illustrating an example of a reactor abnormality determination processing routine executed by a routine 0;

FIG. 5 is a configuration diagram schematically showing a configuration of a power output device 20B according to a modification.

[Explanation of symbols]

20, 20B power output device, 22 motor, 24 inverter circuit, 26 positive bus, 28 negative bus, 30,
30B 1st DC power supply, 32 2nd DC power supply, 38,3
8B reactor, 40 electronic control unit, 42C
PU, 44 ROM, 46 RAM, 52 to 58 current sensor, 60 rotation angle sensor, 70 LED, T1 to T6
Transistors, D1-D6 diodes.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H007 AA17 BB06 CB05 DA05 DB01 DB12 DC02 FA04 5H576 BB06 CC02 DD02 DD07 EE15 GG01 GG04 HA02 HB01 JJ03 JJ17 LL22 LL41 LL55 MM10

Claims (16)

[Claims] An electric motor that is driven to rotate by a polyphase alternating current, an inverter circuit that can supply polyphase alternating current power to the electric motor by switching a plurality of switching elements, and a positive bus and a negative bus that are connected to the inverter circuit. A first power supply, and a second power supply connected to one of the positive bus and the negative bus of the inverter circuit and the neutral point of the electric motor.
A power supply, and neutral point power detection means for detecting neutral point power transmitted and received via a neutral point of the electric motor at at least two points in a rising section or a falling section of the neutral point power; Control means for performing switching control of the switching element of the inverter circuit based on the detected neutral point power. 2. An electric motor rotatingly driven by a polyphase alternating current, an inverter circuit capable of supplying polyphase alternating current power to the electric motor by switching a plurality of switching elements, and one of a positive electrode bus and a negative electrode bus of the inverter circuit Connected to the bus of the motor and the neutral point of the motor.
A power supply, a second power supply connected to the other bus different from the one bus of the inverter circuit and a neutral point of the motor, and a neutral point power transmitted and received via the neutral point of the motor. Neutral point power detecting means for detecting at least two points in the rising section or the falling section of the neutral point power, and switching control of a switching element of the inverter circuit based on the detected neutral point power. A power output device comprising control means. 3. The neutral point power detecting means is means for detecting the neutral point power at at least two points within a half cycle around a peak or a valley of a carrier.
Or the power output device according to 2. 4. The power output apparatus according to claim 3, wherein the at least two points are two points that are 90 degrees out of phase with respect to a peak or a valley of the carrier. 5. The power output device according to claim 1, wherein the neutral point power detecting means is a neutral point current detecting means for detecting a neutral point current flowing to a neutral point of the electric motor. 6. The power output apparatus according to claim 5, further comprising amplitude calculating means for calculating an amplitude of the neutral point current based on the neutral point current detected by said neutral point current detecting means. 7. The power output apparatus according to claim 5, wherein an average calculating unit that calculates an average of the neutral point current based on the neutral point current detected by the neutral point current detecting unit. The power output device, wherein the control means is means for performing switching control of a switching element of the inverter circuit based on an average of the calculated neutral point currents. 8. An abnormality detection device for detecting an abnormality of the power output device according to claim 5, wherein the power output is based on a neutral point current detected by the neutral point current detection means. An abnormality detection device including an abnormality detection unit that detects an abnormality of the device. 9. The abnormality detection device for detecting an abnormality of a power output device according to claim 6, further comprising a reactor connecting the second power supply and a neutral point of the electric motor, wherein the abnormality is calculated by the amplitude calculation means. An abnormality detection device comprising abnormality detection means for detecting an abnormality of the reactor based on the amplitude of the neutral point current. 10. An electric motor that is driven to rotate by polyphase alternating current, an inverter circuit that can supply polyphase alternating current power to the electric motor by switching a plurality of switching elements, and a positive bus and a negative bus that are connected to the inverter circuit. A first power supply, and a second power supply connected to one of the positive bus and the negative bus of the inverter circuit and the neutral point of the electric motor.
A power output method for a power output device comprising: a power source; and a neutral point power transmitted / received via a neutral point of the electric motor, wherein the neutral point power is at least two in a rising section or a falling section of the neutral point power. A power output method that detects at a point and controls switching of a switching element of the inverter circuit based on the detected neutral point power. 11. An electric motor that is driven to rotate by polyphase alternating current, an inverter circuit that can supply multiphase AC power to the electric motor by switching a plurality of switching elements, and one of a positive bus and a negative bus of the inverter circuit. Connected to the bus of the motor and the neutral point of the motor.
A power output method for a power output device, comprising: a power supply; and a second power supply connected to the other bus of the inverter circuit, the bus being different from the one bus, and a neutral point of the motor. Neutral point power transmitted and received via the neutral point is detected at at least two points in a rising section or a falling section of the neutral point power, and based on the detected neutral point power, A power output method for controlling switching of a switching element. 12. The power output method according to claim 10, wherein the neutral point power is detected at at least two points within a half cycle around a peak or a valley of the carrier. 13. The power output method according to claim 12, wherein the at least two points are two points that are 90 degrees out of phase with respect to a peak or a valley of a carrier. 14. The power output method according to claim 10, wherein the neutral point power is a neutral point current flowing to a neutral point of the electric motor. 15. An abnormality detection method for detecting an abnormality of a power output device according to claim 5, wherein the power output is based on a neutral point current detected by the neutral point current detection means. An abnormality detection method for detecting an abnormality in the device. 16. The abnormality detection method for detecting an abnormality of a power output device according to claim 6, further comprising a reactor connecting the second power supply and a neutral point of the electric motor, wherein the abnormality is calculated by the amplitude calculation means. An abnormality detecting method for detecting an abnormality of the reactor based on the amplitude of the neutral point current.