JP7205119B2 - Condition monitor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a state monitoring device, and more particularly to a state monitoring device that monitors the state of a power converter.

2. Description of the Related Art Conventionally, a state monitoring device that monitors the state of a power conversion device is known (see, for example, Patent Literature 1).

The state monitoring device described in Patent Document 1 is connected in series to a positive side of a DC power supply of a power converter, and includes a first resistance element and a second resistance element connected in series with each other. Prepare. Further, the state monitoring device includes a second resistance element group connected in series between the negative side of the DC power supply and the first resistance element group, and including a third resistance element and a fourth resistance element connected in series with each other. Prepare. The state monitoring device also includes a ground resistor connected between the interconnection point of the first resistor group and the second resistor group and the ground point. The state monitoring device also includes a positive feed circuit connected to a connection point between the first resistance element and the second resistance element. A positive voltage from the positive power supply circuit is supplied to a circuit such as an AD conversion circuit provided in the state monitoring device.

Further, the state monitoring device outputs a signal regarding the state of the power conversion device based on the current flowing through the first resistance element group and the current flowing through the second resistance element group to the host control device. Specifically, the state monitoring device obtains information on the voltage Vp applied across the first resistance element, which is determined by the current value flowing through the first resistance element group (first resistance element) and the resistance value of the first resistance element. , is output to a higher control device. In addition, the state monitoring device sends the information of the voltage Vn across the third resistance element, which is determined by the current value flowing through the second resistance element group (third resistance element) and the resistance value of the third resistance element, to a higher order Output to the control device. Note that the resistance value of the first resistance element and the resistance value of the third resistance element are substantially equal.

Here, when a ground fault (a state in which the electric circuit and the ground are electrically connected) does not occur in the power conversion device, no current flows through the ground resistor. It becomes equal to the value of the current flowing through the third resistance element. As a result, voltage Vp and voltage Vn become equal. In addition, when a ground fault occurs in the bus connected to the negative side of the DC power supply, the current flows from the interconnection point toward the negative side of the DC power supply via the ground resistance. A current value flowing through the element becomes larger than a current value flowing through the third resistance element. As a result, voltage Vp becomes larger than voltage Vn. In addition, when a ground fault occurs in the bus connected to the positive side of the DC power supply, current flows from the positive side of the DC power supply to the interconnection point via the ground resistance, so the third resistor A current value flowing through the element becomes larger than a current value flowing through the first resistance element. As a result, voltage Vn becomes greater than voltage Vp. That is, it is possible to determine whether or not a ground fault has occurred and the location of the ground fault based on the relationship between the voltage Vp and the voltage Vn.

Further, when the voltage Vp applied to the first resistance element is detected, the voltage applied to the second resistance element is calculated based on the resistance value of the first resistance element and the resistance value of the second resistance element. Further, when the voltage Vn applied to the third resistance element is detected, the voltage applied to the fourth resistance element is calculated based on the resistance value of the third resistance element and the resistance value of the fourth resistance element. Thereby, the voltage value of the DC power supply is calculated based on the voltage applied to each of the first resistance element, the second resistance element, the third resistance element, and the fourth resistance element. As a result, it becomes possible to determine a DC overvoltage failure of the DC voltage.

JP 2017-166938 A

Here, in the state monitoring device described in Patent Literature 1, the connection point between the first resistance element and the second resistance element is connected to the positive side feeder circuit. Current is flowing from the connection point to the positive feeding circuit. However, in the state monitoring device described in Patent Document 1, failure detection is performed based only on the currents flowing through the first and second resistance elements and the currents flowing through the third and fourth resistance elements. is being done. That is, in the state monitoring device described in Patent Document 1, without considering the current flowing from the connection point of the first resistance element and the second resistance element toward the positive feed circuit (assuming that the current value is zero) and) fault detection is performed. In this case, the effect of shunting part of the current flowing through the first resistance element group toward the positive feed circuit is not taken into consideration. , the current (detected value) flowing through the second resistance element group may deviate from the value of the current actually flowing. For this reason, there is a problem that the failure detection of the power conversion device may not be accurately performed by the state monitoring device.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems described above, and one object of the present invention is to provide a condition monitoring apparatus capable of more accurately detecting failures in a power converter. is.

In order to achieve the above object, a condition monitoring device according to one aspect of the present invention is a condition monitoring device for monitoring the state of a power conversion device, which is connected to the positive side of a DC power supply of the power conversion device and connected in series with each other. and a third resistor connected between the negative side of the DC power supply and the first resistor group and connected in series with each other a second resistance element group including an element and a fourth resistance element; a ground resistance element portion connected between an interconnection point of the first resistance element group and the second resistance element group and a ground point; Between the first power supply unit connected to the first connection point where the element and the second resistance element are connected and supplying power to a predetermined circuit in the condition monitoring device, and the first connection point and the first power supply unit A fifth resistance element or current sensor provided, current flowing through the first resistance element group, current flowing through the second resistance element group, and power based on the current flowing between the first connection point and the first power supply section and a state signal output unit for outputting a signal regarding the state of the conversion device to an external control device.

In the state monitoring device according to one aspect of the present invention, as described above, the current flowing through the first resistance element group, the current flowing through the second resistance element group, and the current flowing between the first connection point and the first power supply section A signal regarding the state of the power conversion device based on the flowing current is output to an external control device. That is, since the current actually flowing between the first connection point and the first feeder is taken into account, the effect of part of the current flowing through the first resistance element group being shunted toward the first feeder is considered. is considered as a signal about the state of the power converter. As a result, each of the (detected value of) the current flowing through the first resistance element group and the (detected value of) the current flowing through the second resistance element group is suppressed from deviating from the value of the actually flowing current. can be done. Thereby, failure detection of the power converter can be performed more accurately.

In the state monitoring device according to the above aspect, preferably, the state signal output section has a first voltage at the first connection point and a second voltage at the second connection point where the third resistance element and the fourth resistance element are connected. , and a third voltage based on the current flowing between the first connection point and the first power supply unit are output to an external control device as signals relating to the state. With this configuration, it is possible to easily calculate the current flowing between the first connection point and the first power supply section using the signal based on the third voltage output to the external control device.

In this case, the state signal output section is preferably configured to output a signal based on the third voltage between the fifth resistance element and the first power supply section to the external control device as the signal regarding the state. ing. With this configuration, by providing the fifth resistance element, a signal based on the third voltage can be output to an external control device. As a result, a signal based on the third voltage can be output to an external control device with a relatively simple configuration.

In the state monitoring device that outputs signals based on each of the first voltage, the second voltage, and the third voltage to an external control device, preferably, the interconnection point is a positive side DC power supply of the power conversion device , and the negative side DC power supply of the power converter connected in series with the positive side DC power supply, and the grounding resistance element section includes a sixth resistance element and a seventh resistance element connected in series with each other. and the state signal output unit is a signal based on each of the first voltage, the second voltage, the third voltage, and the fourth voltage at the third connection point where the sixth resistance element and the seventh resistance element are connected is output to an external control device as a signal relating to the state. With this configuration, when a ground fault occurs on the positive side (the bus) of the positive side DC power supply, the ground resistance element section (the third connection A fourth voltage at the third connection point will be greater than the voltage at the interconnection point (zero) because current will flow through the point) towards the interconnection point. Also, if a ground fault occurs on the negative side (bus line) of the negative side DC power supply, the negative side of the negative side DC power supply The fourth voltage at the third node is less than the voltage (zero) at the interconnection node since the current flows towards (the bus of). Moreover, when the ground fault does not occur, the fourth voltage becomes zero. Therefore, based only on the value of the fourth voltage, it is possible to determine whether or not a ground fault has occurred and the location of the ground fault, thereby facilitating ground fault detection.

In the state monitoring device that outputs a signal based on each of the first voltage, the second voltage, and the third voltage to an external control device, preferably the first voltage, the second voltage, and the third voltage Each is an analog value, and the state signal output unit includes a first conversion unit that converts the first voltage into a digital value, a second conversion unit that converts the second voltage into a digital value, and a third voltage into a digital value. and an output timing control unit that transmits a signal for controlling the timing of outputting the converted digital signal to each of the first conversion unit, the second conversion unit, and the third conversion unit. and including. With this configuration, the output timing control section can collectively control the timing at which each of the first conversion section, the second conversion section, and the third conversion section outputs the digital signal. As a result, compared to the case where each of the first conversion unit, the second conversion unit, and the third conversion unit controls the timing of outputting its own digital signal, the timing control configuration can be simplified. can be done.

In this case, preferably, the output timing control unit synchronizes with the operation of the external control device based on a pulse signal for starting the operation from the external control device, the first conversion unit, the second conversion unit, and , and the third converter, a signal for controlling the output timing of the digital signal is transmitted. Here, when the external control device and the state monitoring device are not synchronized, in order to output a digital signal from each conversion unit within the calculation cycle of the external control device, On the other hand, it is necessary to make the operation of the state detection device sufficiently fast. In contrast, in the present invention, the operation of the state detection device can be made relatively slow by synchronizing it with the operation of the external control device. As a result, an increase in power consumption of the state detection device can be suppressed. In addition, since the current flowing in the state monitoring device can be reduced by slowing down the operation speed, the resistance element in the state monitoring device can be made smaller, and the heat generated in the resistance element can be dissipated. The cooling system for this can be downsized.

The condition monitoring device according to the above aspect preferably further includes a second power supply unit connected to a second connection point where the third resistance element and the fourth resistance element are connected, and supplying power to a predetermined circuit, The state signal output section outputs a current flowing through the first resistance element group, a current flowing through the second resistance element group, a current flowing between the first connection point and the first power supply, and a current flowing between the second connection point and the second power supply. It is configured to output to an external control device a signal regarding the state of the power conversion device based on the current flowing between it and the unit. With this configuration, since the influence of part of the current flowing through the second resistance element group being shunted toward the second power supply section is taken into consideration, the current flowing through the second resistance element group (detection of the current) is considered. value) can be suppressed from deviating from the current value actually flowing. This makes it possible to more accurately detect a failure of the power converter when the second power supply unit is provided.

In this case, preferably, an eighth resistance element is provided between the second connection point and the second power supply section, and the state signal output section outputs the first voltage at the first connection point and the second voltage at the second connection point. 2 voltages, a third voltage based on the current flowing between the first connection point and the first power supply, and a signal based on the fifth voltage between the eighth resistive element and the second power supply. It is configured to output to an external control device as a signal related to. With this configuration, it is possible to easily calculate the current flowing between the second connection point and the second power supply section using the signal based on the fifth voltage output to the external control device. Further, by providing the eighth resistance element, a signal based on the fifth voltage can be output to an external control device, so that a signal based on the fifth voltage can be output to the external control device with a relatively simple configuration. be able to.

ADVANTAGE OF THE INVENTION According to this invention, as mentioned above, failure detection of a power converter can be performed more correctly.

It is a figure for demonstrating the connection of the state-monitoring apparatus and power converter by 1st and 4th embodiment. It is a figure which shows the structure of the condition-monitoring apparatus by 1st Embodiment. 4A and 4B are diagrams for explaining the operation of the power supply voltage monitoring unit of the state monitoring device according to the first embodiment; FIG. It is a figure for demonstrating control of the output timing control part of the condition-monitoring apparatus by 1st Embodiment. 4A and 4B are diagrams for explaining operations of an AD converter and a serial signal conversion unit of the state monitoring device according to the first embodiment; FIG. 4 is a diagram for explaining the operation of the serial signal selector of the state monitoring device according to the first embodiment; FIG. It is an equivalent circuit for explaining the state of the power converter based on the presence or absence of occurrence of a ground fault in the first embodiment. (Fig. 7(a) is an equivalent circuit when no ground fault occurs. Fig. 7(b) is an equivalent circuit when a ground fault occurs on the negative side bus. Fig. 7 ( c) is an equivalent circuit when a ground fault occurs on the positive bus.) It is a figure for demonstrating the connection of the state-monitoring apparatus and power converter by 2nd and 3rd embodiment. It is a figure which shows the structure of the condition-monitoring apparatus by 2nd Embodiment. It is a figure for demonstrating control of the output timing control part of the condition-monitoring apparatus by 2nd Embodiment. It is a figure for demonstrating the operation|movement of the serial signal selection part of the state-monitoring apparatus by 2nd Embodiment. It is an equivalent circuit for explaining the state of the power converter based on the presence or absence of occurrence of a ground fault in the second embodiment. (Fig. 12(a) is an equivalent circuit when no ground fault occurs. Fig. 12(b) is an equivalent circuit when a ground fault occurs on the negative bus. Fig. 12 ( c) is an equivalent circuit when a ground fault occurs on the positive bus.) It is a figure which shows the structure of the condition-monitoring apparatus by 3rd Embodiment. FIG. 14 is a diagram for explaining the operation of the power supply voltage monitoring unit of the state monitoring device according to the third embodiment; FIG. 11 is a diagram for explaining control of an output timing control unit of the state monitoring device according to the third embodiment; It is a figure for demonstrating the operation|movement of the serial signal selection part of the condition-monitoring apparatus by 3rd Embodiment. It is an equivalent circuit for explaining the state of the power conversion device based on the presence or absence of occurrence of a ground fault in the third embodiment. (Fig. 17(a) is an equivalent circuit when no ground fault occurs. Fig. 17(b) is an equivalent circuit when a ground fault occurs on the negative bus. Fig. 17 ( c) is an equivalent circuit when a ground fault occurs on the positive bus.) It is a figure which shows the structure of the condition-monitoring apparatus by 4th Embodiment. It is a figure for demonstrating control of the output timing control part of the condition-monitoring apparatus by 4th Embodiment.

Embodiments embodying the present invention will be described below with reference to the drawings.

[First embodiment]
The configuration of the condition monitoring device 100 according to the first embodiment will be described with reference to FIGS. 1 to 7. FIG.

First, referring to FIG. 1, a schematic configuration of the condition monitoring device 100 will be described. As shown in FIG. 1, the state monitoring device 100 is provided to monitor the state of the power conversion device 800 (whether there is a ground fault or a DC overvoltage fault). The state monitoring device 100 is connected between a positive bus 800a and a negative bus 800b of the power conversion device 800 .

Further, the power conversion device 800 is provided with a diode converter 800c that converts an AC voltage into a DC voltage (positive voltage) E. As shown in FIG. The power converter 800 is also provided with a two-level inverter 800d that converts the DC voltage E converted by the diode converter 800c into an AC voltage and outputs the AC voltage to a load (not shown). State monitoring device 100 is provided between diode converter 800c and inverter 800d. The diode converter 800c is an example of the "DC power supply" in the claims.

Here, the configuration of the state monitoring device 100 will be described with reference to FIG. It should be noted that the current Ip1 and the current Ip2 in FIG. 2 are the currents flowing through the resistive element 1a and the resistive element 1b, respectively, which will be described later. A current In is a current that flows through the resistive element group 2, which will be described later. A current Ig is a current that flows through the ground resistance element 3, which will be described later. A current Ic is a current flowing through a resistive element 6, which will be described later. A voltage Vp1 and a voltage Vp2 are the voltage across the resistor element 1a and the voltage across the resistor element 1b, respectively. The voltage Vp1 is also the voltage at the connection point A, which will be described later. A voltage Vn1 and a voltage Vn2 are the voltage applied across the resistor element 2a and the voltage applied across the resistor element 2b, respectively. The voltage Vn1 is also the voltage at the connection point B, which will be described later. A voltage Vc is a voltage between the resistive element 6 and the positive voltage feeder 4 .

(Configuration of condition monitoring device)
As shown in FIG. 2, the state monitoring device 100 includes a resistance element group 1 connected to the positive side (positive side bus 800a) of a diode converter 800c (see FIG. 1). Resistive element group 1 includes a resistive element 1a and a resistive element 1b connected in series. The resistance element group 1 is an example of the "first resistance element group" in the scope of claims. Also, the resistance element 1a and the resistance element 1b are examples of the "first resistance element" and the "second resistance element" in the claims, respectively.

State monitoring device 100 also includes resistance element group 2 connected between resistance element group 1 and the negative side (negative side bus 800b) of diode converter 800c. Resistance element group 2 includes a resistance element 2a and a resistance element 2b connected in series. The resistance element group 2 is an example of the "second resistance element group" in the scope of claims. Also, the resistance element 2a and the resistance element 2b are examples of the "third resistance element" and the "fourth resistance element" in the claims, respectively.

The state monitoring device 100 also includes a ground resistance element 3 connected between the interconnection point M of the resistance element group 1 and the resistance element group 2 and the ground point G. As shown in FIG. The ground resistance element 3 is an example of the "ground resistance element section" in the scope of claims.

The state monitoring device 100 also includes a positive voltage feeder 4 connected to a connection point A where the resistance element 1a and the resistance element 1b are connected. Specifically, the connection point A and the positive voltage feeder 4 are connected via a resistive element 6, which will be described later. In addition, the positive voltage from the positive voltage feeding unit 4 is fed to operational amplifiers 70a to 70c and AD converters 71a to 71c provided in the state monitoring device 100 (as a positive side voltage). That is, the positive power supply voltage Vcc required for the operation of the condition monitoring device 100 is output from the positive voltage power supply unit 4 . A capacitor 5 is connected between the output side of the positive voltage feeder 4 and the interconnection point M. As shown in FIG. Capacitor 5 is charged by positive power supply voltage Vcc output from positive voltage feeder 4 . With this configuration, the (positive) voltage necessary for operation does not need to be supplied from an external power source, so the state monitoring device 100 can be made smaller. The connection point A is an example of the "first connection point" in the scope of claims. Further, the operational amplifiers 70a to 70c and the AD converters 71a to 71c are examples of the "predetermined circuit" in the claims. Also, the positive voltage feeder 4 is an example of a "first feeder" in the scope of claims.

The state monitoring device 100 also includes a resistive element 6 provided between the connection point A and the positive voltage power supply section 4 . The resistance element 6 is an example of a "fifth resistance element" in the scope of claims.

The state monitoring device 100 is also provided with a power supply circuit portion 100a including a state signal output section 7, which will be described later.

Here, in the first embodiment, the state monitoring device 100 detects the current (current Ip1 and current Ip2) flowing through the resistance element group 1, the current In flowing through the resistance element group 2, and the connection point A and the positive voltage feeding section 4. and a state signal output unit 7 for outputting a signal regarding the state of the power conversion device 800 based on the current Ic flowing between and to the host control device 900 . Note that the control device 900 is an example of an "external control device" in the scope of claims.

Specifically, the state signal output unit 7 outputs the voltage Vp1 at the connection point A, the voltage Vn1 at the connection point B where the resistance element 2a and the resistance element 2b are connected, and the connection point A and the positive voltage feeding unit 4 ( A signal based on each of the voltages Vc based on the current Ic flowing between the resistor element 6) is output to the host control device 900 as a signal regarding the state of the power conversion device 800. FIG. Each of voltage Vp1, voltage Vn1, and voltage Vc is an analog value. Also, the voltage Vp1 and the voltage Vn1 are examples of the "first voltage" and the "second voltage" in the claims, respectively. Also, the voltage Vc and the connection point B are examples of the "third voltage" and the "second connection point" in the claims, respectively.

The configuration and operation of the state signal output section 7 in the first embodiment will be described in detail below.

(Configuration of status signal output unit)
The state signal output section 7 includes an operational amplifier 70a, an operational amplifier 70b, and an operational amplifier 70c. The state signal output unit 7 also includes an AD converter 71a, an AD converter 71b, and an AD converter 71c. State signal output section 7 also includes a power supply voltage monitoring section 72 and an output timing control section 73 . The state signal output unit 7 also includes a serial signal conversion unit 74a, a serial signal conversion unit 74b, and a serial signal conversion unit 74c. The state signal output unit 7 also includes a serial signal selection unit 75 and an E/O (Electrical/Optical) conversion unit 76 . The operational amplifier 70a is connected to the connection point A. Since the operational amplifier 70a has a relatively high input resistance compared to the resistance element 6, almost no current flows through the operational amplifier 70a.

A voltage Vp1 at the connection point A is input to the operational amplifier 70a. The operational amplifier 70a converts (steps down) the input voltage Vp1 to a voltage Vpa and outputs the same. Also, the voltage Vn1 at the connection point B is input to the operational amplifier 70b. The operational amplifier 70b converts (steps down) the input voltage Vn1 to a voltage Vna and outputs the same. A voltage Vc between the resistive element 6 and the positive voltage feeder 4 is input to the operational amplifier 70c. The operational amplifier 70c converts (steps down) the input voltage Vc to a voltage Vca and outputs the same.

A voltage Vpa from the operational amplifier 70a is input to the AD converter 71a. A voltage Vna from the operational amplifier 70b is input to the AD converter 71b. A voltage Vca from the operational amplifier 70c is input to the AD converter 71c. The AD converters 71a and 71b are examples of the "first converter" and the "second converter" in the claims, respectively. Also, the AD converter 71c is an example of the "third converter" in the scope of claims.

The voltage of the capacitor 5 (positive power supply voltage Vcc) is input to the power supply voltage monitoring unit 72 . The power supply voltage monitoring unit 72 outputs a signal V _SET (logic signal) to the output timing control unit 73 . At time t (see FIG. 3) at which the voltage (positive side power supply voltage Vcc) input to the power supply voltage monitoring unit 72 exceeds a predetermined threshold voltage value Vth (see FIG. 3), the logic value of the signal V _SET is It changes from 0 to 1. The threshold voltage value Vth is set in advance as a voltage value at which the circuits of the state monitoring device 100 (such as the operational amplifiers 70a to 70c and the AD converters 71a to 71c) become operable.

Here, in the first embodiment, the output timing control unit 73 outputs a signal for controlling the timing of outputting the converted digital signal to each of the AD converters 71a, 71b, and 71c. to send. Specifically, the output timing control unit 73 transmits a signal _{S_INTA} that controls the timing at which the AD converter 71a outputs the digital signal _DVA . The output timing control unit 73 also transmits a signal _{S_INTB} for controlling the timing at which the AD converter 71b outputs the digital signal _DVB . The output timing control unit 73 also transmits a signal _{S_INTC} that controls the timing at which the AD converter 71c outputs the digital signal _DVC .

Further, when the logic value of the signal _VSET changes to 1, the output timing control section 73 starts the operation of controlling the AD converters 71a to 71c in a constant cycle.

Here, the control operation of the output timing control section 73 (see FIG. 2) will be described with reference to FIG. As shown in FIG. 4, the output timing control section 73 is configured to operate based on a CLK signal (see FIG. 4(a)) having a predetermined cycle. Further, the output timing control unit 73 includes a signal of Bit0 (see FIG. 4B), a signal of Bit1 (see (c) of FIG. 4), a signal of Bit2 (see (d) of FIG. 4), and a signal of Bit3. There is a signal (see FIG. 4(e)). The cycle of the signal of Bit0 is twice the cycle of the CLK signal. Also, the period of the signal of Bit1 is four times the period of the CLK signal. Also, the period of the signal of Bit2 is eight times the period of the CLK signal. Also, the period of the signal of Bit3 is 16 times the period of the CLK signal.

The signal S _INTA , the signal S _INTB , and the signal S _INTC are configured to be in a High state (logical value of 1) based on the values of Bits 0-3. Specifically, the value (hereinafter referred to as the logical product) of the 4-bit values expressed in the order of Bit3, Bit2, Bit1, and Bit0 from the upper side in decimal is 1 (Bit0 = 1, Bit1 = 0, Bit2 =0, Bit3=0), the logic value of the signal _{S_INTA} changes to 1 (see FIG. 4(f)). Also, when the logical product is 3 (Bit0=1, Bit1=1, Bit2=0, Bit3=0), the logical value of the signal S _INTB changes to 1 (see FIG. 4(g)). Also, when the logical product is 5 (Bit0=1, Bit1=0, Bit2=1, Bit3=0), the logical value of the signal S _INTC changes to 1 (see FIG. 4(h)). In this case, the period of each of the signals S _INTA , S _INTB , and S _INTC is period T, which is 16 times the period of the CLK signal. In FIG. 4, logical products based on the values of Bits 0 to 3 are shown in parentheses (for example, (1)).

Next, referring to FIG. 5, signal conversion in the AD converters 71a to 71c will be described. In FIG. 5, only the AD converter 71a will be described as an example, but the same applies to the AD converters 71b and 71c.

As shown in FIG. 5, when the logic value of the signal S _INTA from the output timing control unit 73 changes to 1 (see FIG. 5(a)), the AD converter 71a converts the signal into a signal (see FIG. 5(b)). becomes 1, and signal conversion (analog to digital conversion) is started. When the time _TCHG (which is shorter than the time Tc during which the signal S _INTA is logically 1) has elapsed since the signal conversion was started, the conversion process ends and the logical value of the signal conversion signal becomes 0, and AD conversion is performed. A digital signal D _VA (conversion result data) is output from the device 71a. A digital signal D _VB (see FIG. 2) and a digital signal D _VC (see FIG. 2) are output from the AD converters 71b and 71c, respectively.

The digital signal D _VA , the digital signal D _VB , and the digital signal D _VC are respectively converted into a serial signal converter 74a (see FIG. 2), a serial signal converter 74b (see FIG. 2), and a serial signal converter 74c (see FIG. 2). is entered in Then, as shown in FIG. 5(d), the serial signal conversion unit 74a converts the serial signal S _VA (FIG. 5(d)) after time T _DLY after the AD converter 71a starts outputting the digital signal D _VA . reference) is started.

Although the description is omitted, the same processing is performed in the serial signal converters 74b and 74c. Specifically, the serial signal converter 74b converts the digital signal D _VB from the AD converter 71b into a serial signal S _VB (see FIG. 2). The serial signal converter 74c also converts the digital signal _DVC from the AD converter 71c into a serial signal _SVC (see FIG. 2).

In general, the digital signal output from the AD converter requires some time from the start of output until it stabilizes. For this reason, it is desirable to have some margin such as time _{T_DLY} from when the digital signal is output from the AD converter to when the conversion processing to the serial signal is started. Also, the value of the time _{T_DLY} may be determined from the specifications of the AD converter used. There are various forms of serial signals depending on the output method. For example, a UART (Universal Asynchronous Receiver Transmitter) system, which outputs serial data bit by bit in synchronization with a clock signal, is used.

The serial signals S _VA to S _VC output from the serial signal converters 74a to 74c are also input to the serial signal selector 75 (see FIG. 2). The serial signal selector 75 selects an actually existing serial signal from among the serial signals S _VA to S _VC and outputs it as a serial signal S _E (see FIG. 1). That is, as shown in FIG. 6, the serial signal selector 75 selects serial signals S _VA (see FIG. 6(a)), serial signals S _VB (see FIG. 6(b)), and The sum with the serial signal S _VC (see FIG. 6(c)) is output as the serial signal S _E . The output timing control section 73 controls the output timings of the serial signals S _VA to S _VC so that they do not overlap (see FIG. 4). circuit becomes unnecessary. That is, it is possible to configure the serial signal selection unit 75 only with a simple OR circuit.

Also, the serial signal SE is input to the _E /O converter 76 (see FIG. 2). The E/O converter 76 is converted into an optical serial signal S _L (that is, a state monitoring signal) (see FIGS. 2 and 6(d)) and sent to the host controller 900 (see FIG. 2) via the optical cable 77 (see FIG. 2). (see FIG. 2). The optical serial signal SL input to the control device 900 is converted into status monitoring data S _data by an O/E (Optical/Electrical) conversion section _900a (see FIG. 2) in the control device 900 . This state monitoring data _{S_data} is taken into an arithmetic unit (not shown), and the arithmetic unit performs arithmetic operations for controlling the operation of power converter 800 and arithmetic operations for detecting a ground fault or DC overvoltage fault. is executed. Note that the optical serial signal _SL is an example of a "state-related signal" in the scope of claims.

(Method for judging ground fault and DC overvoltage fault)
FIG. 7 is a circuit configuration diagram (equivalent circuit diagram) for explaining voltage and current states depending on the presence or absence of a ground fault. In FIG. 7, the power supply circuit portion 100a (see FIG. 2) of the condition monitoring device 100 is connected between the connection point A and the interconnection point M, and the current Ic flows through the power supply circuit portion 100a. there is

FIG. 7(a) is an equivalent circuit when there is no ground fault. In this case, the current Ig does not flow through the ground resistance element 3 (Ig=0), and the current Ig can be ignored. In this case, the following equations (1) and (2) hold.

Moreover, FIG.7(b) is an equivalent circuit when the negative side bus-line 800b of the power converter device 800 is earth-faulted. In this case, the ground resistance element 3 and the resistance element group 2 are connected in parallel, and the following formula (3) holds.

In this case, the following formula (4) holds.

FIG. 7(c) is an equivalent circuit when the positive bus 800a of the power converter 800 is grounded. In this case, the ground resistance element 3 and the resistance element group 1 are connected in parallel, and the following equation (5) holds.

In this case, the following formula (6) holds.

That is, when the above equations (1) and (2) hold, no ground fault has occurred. Further, when the value of the right side of the above equation (4) is a positive value, a ground fault has occurred in the negative bus 800b. Based on the magnitude of the current Ig calculated from the above equation (4), it is also possible to detect (know) the magnitude of the ground fault on the negative side. Further, when the value of the right side of the above equation (6) is a positive value, a ground fault has occurred in the positive bus line 800a. Based on the magnitude of the current Ig calculated from the above equation (6), it is also possible to detect (know) the magnitude of the ground fault on the negative side. It should be noted that the current values of the above equations (1) to (6) are calculated using the following equations (7) to (9), which will be described later.

The current Ip1 is calculated from the resistance value R1p of the resistive element 1a and the voltage across the resistive element 1a (detected voltage at the connection point A) Vp1 by the following equation (7).

In addition, since the voltage across the resistance element 6 is the difference between the voltage Vp1 at the connection point A and the voltage Vc between the positive voltage feeding section 4 and the resistance element 6, the current Ic is given by the following equation (8 ). Ricc is the resistance value of the resistance element 6 .

Also, the current In is calculated from the resistance value R1n of the resistance element 2a and the voltage across the resistance element 2a (detected voltage at the connection point B) Vn1 by the following equation (9).

Here, the DC voltage E is calculated by summing the voltage across each resistance element connected between the positive bus 800a and the negative bus 800b, as shown in the following equation (10). .

Vp1 and Vn1 in the right side of the above equation (10) are the detected voltages at connection point A and connection point B, respectively. As for Vp2, the following equation (11) is established by the resistance value R2p of the resistance element 1b and the current Ip2 flowing through the resistance element 1b. In this case, the following formula (12) holds based on the following formula (11) and the above formula (1). Then, based on the following formula (12), the above formula (7), and the above formula (8), the following formula (13) holds. Voltage Vp2 is calculated from the following equation (13).

As for Vn2, the following equation (14) is established by the resistance value R2n of the resistance element 2b and the current In flowing through the resistance element 2b. In this case, the following formula (15) holds based on the following formula (14) and the above formula (9). Voltage Vn2 is calculated from the following equation (15).

The magnitude of the DC voltage E is calculated from the detected voltages at the connection points A and B, Vp2 calculated by the above equation (13), and Vn2 calculated by the above equation (15).

As described above, by using a common circuit for both ground fault detection and DC overvoltage fault detection, it is possible to suppress an increase in the number of detection circuits, and the configuration of the detection circuit can be simplified.

(Effect of the first embodiment)
The following effects can be obtained in the first embodiment.

In the first embodiment, as described above, the power conversion device 800 is based on the current flowing through the resistance element group 1, the current flowing through the resistance element group 2, and the current flowing between the connection point A and the positive voltage feeding section 4. The state monitoring device 100 is configured so as to include a state signal output section 7 that outputs a signal regarding the state of to the control device 900 . As a result, the current actually flowing between the connection point A and the positive voltage feeder 4 is taken into account, so that part of the current flowing through the resistance element group 1 is diverted toward the positive voltage feeder 4. Effects are considered as signals about the state of power converter 100 . As a result, the (detected value) of the current flowing through the resistance element group 1 and the (detected value) of the current flowing through the resistance element group 2 can be prevented from deviating from the actual current value. . Thereby, the failure detection of the power conversion device 800 can be performed more accurately.

Further, in the first embodiment, as described above, the state signal output unit 7 outputs the voltage Vp1 at the connection point A, the voltage Vn1 at the connection point B where the resistance element 2a and the resistance element 2b are connected, and the connection point The state monitoring device 100 is configured to output a signal based on each of the voltages Vc based on the current flowing between A and the positive voltage feeding section 4 to the control device 900 as a signal regarding the state of the power conversion device 800. . As a result, the current flowing between the connection point A and the positive voltage feeding section 4 can be easily calculated using the signal based on the voltage Vc output to the control device 900 .

Further, in the first embodiment, as described above, the state signal output unit 7 controls the signal based on the voltage Vc between the resistive element 6 and the positive voltage power supply unit 4 as a signal regarding the state of the power conversion device 800. Condition monitoring device 100 is configured to output to device 900 . Accordingly, by providing the resistance element 6, a signal based on the voltage Vc can be output to the control device 900. FIG. As a result, a signal based on voltage Vc can be output to control device 900 with a relatively simple configuration.

In the first embodiment, as described above, the state signal output unit 7 includes the AD converter 71a that converts the voltage Vp1 into a digital value, the AD converter 71b that converts the voltage Vn1 into a digital value, the voltage Vc and an AD converter 71c that converts to digital values. Then, the state signal output unit 7 transmits a signal for controlling the timing of outputting the converted digital signal to each of the AD converter 71a, the AD converter 71b, and the AD converter 71c. Condition monitoring device 100 is configured to include 73 . Thus, the output timing control section 73 can collectively control the timing at which each of the AD converters 71a, 71b, and 71c outputs a digital signal. As a result, compared to the case where each of the AD converters 71a, 71b, and 71c controls the timing of outputting its own digital signal, the timing control configuration can be simplified. can be done.

[Second embodiment]
Next, the configuration of the condition monitoring device 200 according to the second embodiment will be described with reference to FIGS. 8 to 12. FIG. Unlike the configuration of the state monitoring device 100 according to the first embodiment, the state monitoring device 200 of the second embodiment has both the diode converter 801c that is the positive side power source and the diode converter 801d that is the negative side power source. It is connected. In addition, the structure similar to the said 1st Embodiment attaches|subjects the same code|symbol as 1st Embodiment, and abbreviate|omits description while it is illustrated.

First, referring to FIG. 8, a schematic configuration of the state monitoring device 200 will be described. As shown in FIG. 8, the state monitoring device 200 is provided to monitor the state of the power conversion device 801 (whether there is a ground fault or a DC overvoltage fault). State monitoring device 200 is connected between positive bus 801 a and negative bus 801 b of power conversion device 801 .

Further, the power conversion device 801 is provided with a diode converter 801c that converts an AC voltage into a DC voltage (positive voltage) Ep. The power conversion device 801 is also provided with a diode converter 801d that is connected in series with the diode converter 801c and converts an AC voltage into a DC voltage (negative voltage) En. The diode converter 801c is an example of a "positive DC power supply" and a "DC power supply" in the claims. Also, the diode converter 801d is an example of a "negative side DC power supply" and a "DC power supply" in the scope of claims.

State monitoring device 200 is connected between diode converter 801c and diode converter 801d via intermediate potential line 801e. The intermediate potential line 801e has an intermediate potential between the positive bus line 801a and the negative bus line 801b. Specifically, the potential of the intermediate potential line 801e is substantially zero. That is, the DC voltage (positive voltage) Ep is the voltage between the positive bus line 801a and the intermediate potential line 801e. A DC voltage (negative voltage) En is a voltage between the negative bus 801b and the intermediate potential line 801e. The intermediate potential line 801e is connected to the interconnection point M (see FIG. 9).

The power conversion device 801 also has three levels for converting the DC voltage Ep converted by the diode converter 801c and the DC voltage En converted by the diode converter 801d into AC voltages and outputting them to a load (not shown). of inverter 801f is provided. State monitoring device 200 is provided between diode converters 801c and 801d and inverter 801f.

Here, the configuration of the state monitoring device 200 will be described with reference to FIG. A current Ig in FIG. 9 is a current flowing through the ground resistance element group 13, which will be described later. A voltage Vg is a voltage at a connection point C where a resistive element 13a and a resistive element 13b, which will be described later, are connected. The voltage Vg is also the voltage applied across the resistance element 13a, which will be described later. Note that the connection point C and the voltage Vg are examples of the "third connection point" and the "fourth voltage" in the scope of claims, respectively.

(Configuration of condition monitoring device)
As shown in FIG. 9, the condition monitoring device 200 includes a ground resistance element group 13 connected between the interconnection point M and the ground point G. As shown in FIG. Ground resistance element group 13 includes a resistance element 13a and a resistance element 13b connected in series. The resistance element 13a is connected to the interconnection point M, and the resistance element 13b is connected to the ground point G. The ground resistance element group 13 is an example of the "ground resistance element section" in the scope of claims. Also, the resistance element 13a and the resistance element 13b are examples of the "sixth resistance element" and the "seventh resistance element" in the claims, respectively.

Moreover, the state monitoring device 200 is provided with a power supply circuit portion 200a including a state signal output section 17, which will be described later.

Here, in the second embodiment, the state monitoring device 200 includes the state signal output section 17 . The state signal output unit 17 is configured to output signals based on each of the voltage Vp1, the voltage Vn1, the voltage Vc, and the voltage Vg at the connection point C to the control device 900 as signals regarding the state of the power conversion device 801. ing. Note that the voltage Vg is an analog value.

The configuration and operation of the state signal output unit 17 according to the second embodiment will be described in detail below.

(Configuration of status signal output unit)
The state signal output section 17 includes an operational amplifier 70d. Moreover, the state signal output unit 17 includes an AD converter 71d. The state signal output section 17 also includes an output timing control section 173 . The state signal output section 17 also includes a serial signal conversion section 74d. The state signal output unit 17 also includes a serial signal selection unit 175 . Note that the operational amplifier 70d is connected to the connection point C. Also, the operational amplifier 70d and the AD converter 71d are examples of the "predetermined circuit" in the claims.

A voltage Vg at the connection point C is input to the operational amplifier 70d. The operational amplifier 70d converts (steps down) the input voltage Vg to a voltage Vga and outputs the same.

A voltage Vga from the operational amplifier 70d is input to the AD converter 71d.

In the second embodiment, the output timing control unit 173 controls the timing of outputting the converted digital signal to each of the AD converters 71a, 71b, 71c, and 71d. send a signal to Specifically, the output timing control unit 173 transmits a signal S _INTD for controlling the timing at which the AD converter 71d outputs the digital signal _DVD in addition to the signal S _INTA , the signal S _INTB , and the signal S _INTC . .

Further, when the logic value of the signal _{V_SET} changes to 1, the output timing control section 173 starts the operation of controlling the AD converters 71a to 71d at regular intervals.

As shown in FIG. 10, when the logical product is 7 (Bit0=1, Bit1=1, Bit2=1, Bit3=0), the logical value of the signal S _INTD changes to 1 (see FIG. 10(i)). do. Note that the period of the signal _SINTD is a period T that is 16 times the period of the CLK signal. 10(a) to (h) are the same as those of FIGS. 4(a) to (h), so description thereof will be omitted.

Then, based on the fact that the logic value of the signal S _INTD has changed to 1, the digital signal D _VD (conversion result data) (see FIG. 9) is output from the AD converter 71d.

The digital signal DVD output from the AD converter _71d is input to the serial signal converter 74d (see FIG. 9). The serial signal converter 74d converts the input digital signal _{DVD into a serial signal S VD (} see FIG. 9). This processing is the same as the processing in the serial signal converters 74a to 74c described in the first embodiment, so detailed description will be omitted.

The serial signals S _VA to S _VD output from the serial signal converters 74 a to 74 d are also input to the serial signal selector 175 . The serial signal selector 175 selects an actually existing serial signal from among the serial signals S _VA to S _VD and outputs it as a serial signal S _E . That is, the serial signal selection unit 175 selects the serial signal S _VA (see FIG. 11A), the serial signal S _VB (see FIG. 11B), and the serial signal S _VC (see FIG. 11) along the time axis. (c)) and the serial signal S _VD (see FIG. 11(d)) is output as the serial signal S _E (see FIG. 11(e)). The output timing control section 173 controls the output timings of the serial signals S _VA to S _VD so that they do not overlap (see FIG. 11).

(Method for judging ground fault and DC overvoltage fault)
FIG. 12 is a circuit configuration diagram (equivalent circuit diagram) for explaining voltage and current states depending on the presence or absence of a ground fault. In FIG. 12, the power supply circuit portion 200a (see FIG. 9) of the condition monitoring device 200 is connected between the connection point A and the interconnection point M, and the power supply circuit portion 200a is shown to carry a current Ic. there is

FIG. 12(a) is an equivalent circuit when there is no ground fault. In this case, the current Ig does not flow through the ground resistance element group 13 (see FIG. 9) (Ig=0), and the voltage applied to the resistance element 13a becomes zero (Vg=0). That is, if the sensed voltage Vg is zero, no ground fault has occurred.

Moreover, FIG.12(b) is an equivalent circuit when the negative side bus-line 801b of the power converter 801 is grounded. In this case, current Ig flows through the path of diode converter 801d, intermediate potential line 801e, interconnection point M, ground resistance element group 13, negative side bus 801b, and diode converter 801d. In this case, the following formula (16) holds. R1g is the resistance value of the resistance element 13a.

In this case, since the potential at the connection point C is lower than the potential at the connection point M, which is zero, in the direction in which the current Ig flows (the direction from the connection point M to the connection point C), Vg<0. . Therefore, when Vg<0, the negative bus 801b is grounded. It is also possible to detect (know) the scale of the ground fault on the negative side based on the magnitude of the current Ig calculated from the above equation (16).

FIG. 12(c) is an equivalent circuit when the positive bus 801a of the power converter 801 is grounded. In this case, current Ig flows through the path of diode converter 801c, positive bus 801a, ground resistance element group 13, interconnection point M, intermediate potential line 801e, and diode converter 801c.

In this case, the potential of the connection point C becomes higher than the potential of the connection point M, which is zero, from the direction in which the current Ig flows (the direction from the connection point C to the interconnection point M), so Vg>0. . Therefore, when Vg>0, the positive bus 801a is grounded. It is also possible to detect (know) the scale of the ground fault on the negative side based on the magnitude of the current Ig calculated from the above equation (16).

Also, the DC voltage Ep is calculated by summing the voltage Vp1 across the resistance element 1a and the voltage Vp2 across the resistance element 1b, as shown in the following equation (17).

Then, the DC voltage Ep is calculated from the voltage Vp1 detected by the state monitoring device 200 and the voltage Vp2 calculated based on the above equation (13).

The DC voltage En is calculated by summing the voltage Vn1 across the resistance element 2a and the voltage Vn2 across the resistance element 2b, as shown in Equation (18) below.

Then, the DC voltage En is calculated from the voltage Vn1 detected by the state monitoring device 200 and the voltage Vn2 calculated based on the above equation (15).

As described above, it is possible to individually determine the DC overvoltage failure of each of the diode converter 801c, which is the positive-side DC power supply, and the diode converter 801d, which is the negative-side DC power supply.

Other configurations of the second embodiment are the same as those of the first embodiment.

(Effect of Second Embodiment)
The following effects can be obtained in the second embodiment.

In the second embodiment, as described above, the state signal output unit 17 outputs the voltage Vp1, the voltage Vn1, the voltage Vc, and the voltage Vg at the connection point C where the resistance elements 13a and 13b are connected. The state monitoring device 200 is configured to output a signal based on the power conversion device 801 to the control device 900 as a signal regarding the state of the power conversion device 801 . As a result, when a ground fault occurs on the positive side (bus line) of the diode converter 801c, from the positive side (bus line) of the diode converter 801c, via the ground resistance element group 13 (connection point C), Since the current flows toward the interconnection point M, the voltage Vg at the interconnection point C becomes larger than the voltage at the interconnection point M (zero). Further, when a ground fault occurs on the negative side (bus line) of the diode converter 801d, from the interconnection point M, via the ground resistance element group 13 (connection point C), the negative side ( ), the voltage Vg at node C becomes smaller than the voltage at node M (zero). Also, when no ground fault occurs, the voltage Vg becomes zero. Therefore, it is possible to determine the presence or absence of a ground fault and the location of the ground fault based only on the value of the voltage Vg, thereby facilitating ground fault detection.

Other effects of the second embodiment are the same as those of the first embodiment.

[Third Embodiment]
Next, the configuration of the condition monitoring device 300 according to the third embodiment will be described with reference to FIGS. 8 and 13 to 17. FIG. A condition monitoring device 300 according to the third embodiment includes a negative voltage power supply unit 8 in addition to the configuration of the condition monitoring device 200 according to the second embodiment. In addition, the structure similar to the said 2nd Embodiment attaches|subjects the same code|symbol as 2nd Embodiment, and it abbreviate|omits description while it is illustrated.

First, as shown in FIGS. 8 and 13, the state monitoring device 300 is provided to monitor the state of the power conversion device 801 (whether there is a ground fault or a DC overvoltage fault).

(Configuration of condition monitoring device)
As shown in FIG. 13, the condition monitoring device 300 includes a negative voltage power supply section 8 connected to the connection point B. As shown in FIG. The negative voltage from the negative voltage feeding section 8 is fed to the operational amplifiers 70a to 70e and the AD converters 71a to 71e provided in the state monitoring device 300 (as negative side voltage). That is, the negative power supply voltage Vee required for the operation of the state monitoring device 300 is output from the negative voltage power supply unit 8 . This makes it possible to operate the state monitoring device 300 more stably than when the state monitoring device 300 is operated only by the positive voltage from the positive voltage power supply section 4 . The operational amplifier 70e and the AD converter 71e are examples of the "predetermined circuit" in the scope of claims. Also, the negative voltage feeder 8 is an example of a "second feeder" in the scope of claims.

A capacitor 9 is connected between the output side of the negative voltage feed section 8 and the interconnection point M. As shown in FIG. The capacitor 9 is charged with the negative side power supply voltage Vee output from the negative voltage power supply section 8 .

Moreover, the state monitoring device 300 includes a resistive element 10 provided between the connection point B and the negative voltage power supply section 8 . The resistance element 10 is an example of the "eighth resistance element" in the scope of claims.

Moreover, the state monitoring device 300 is provided with a power supply circuit portion 300a including a state signal output section 27, which will be described later.

Here, in the third embodiment, the state monitoring device 300 controls the current (current Ip1 and current Ip2) flowing through the resistance element group 1, the current In flowing through the resistance element group 2, A signal relating to the state of the power conversion device 801 is output to the control device 900 based on the current Ic flowing between the ground resistance element group 13, the current Ig flowing through the ground resistance element group 13, and the current Ie flowing between the connection point B and the negative voltage feeding section 8. A state signal output unit 27 is provided.

Specifically, the state signal output unit 27 outputs the voltage Vp1 at the connection point A, the voltage Vn1 at the connection point B, the voltage Vc, the voltage Vg, and the voltage between the connection point B and the negative voltage power supply unit 8 (resistive element 10). A signal based on each of the voltages Ve based on the current Ie flowing therebetween is configured to be output to the control device 900 as a signal regarding the state of the power conversion device 801 . Note that the voltage Ve is an analog value. Also, the voltage Ve is an example of the "fifth voltage" in the claims.

The configuration and operation of the state signal output section 27 according to the third embodiment will be described in detail below.

(Configuration of status signal output unit)
The state signal output section 27 includes an operational amplifier 70e. Moreover, the state signal output unit 27 includes an AD converter 71e. The state signal output section 27 also includes a power supply voltage monitoring section 272 and an output timing control section 273 . The state signal output section 27 also includes a serial signal conversion section 74e. The state signal output section 27 also includes a serial signal selection section 275 .

A voltage Ve between the connection point B and the negative voltage feeder 8 is input to the operational amplifier 70e. The operational amplifier 70e converts (steps down) the input voltage Ve into a voltage Vea and outputs the same.

A voltage Vea from the operational amplifier 70e is input to the AD converter 71e.

The voltage of the capacitor 5 (positive power supply voltage Vcc) and the voltage of the capacitor 9 (negative power supply voltage Vee) are input to the power supply voltage monitoring unit 272 . The power supply voltage monitoring section 272 outputs a signal V _SET (logic signal) to the output timing control section 273 . The input voltage (positive power supply voltage Vcc) becomes equal to or higher than a predetermined threshold voltage value Vthp (see FIG. 14), and the input voltage (negative power supply voltage Vee) exceeds a predetermined threshold voltage value Vthn (see FIG. 14). 14), the logical value of the signal V-- _SET changes from 0 to 1 (see FIG. 14). The threshold voltage values Vthp and Vthn are set in advance as voltage values at which the circuits of the state monitoring device 300 (such as the operational amplifiers 70a to 70e and the AD converters 71a to 71e) become operable.

Further, when the logic value of the signal _{V_SET} changes to 1, the output timing control section 273 starts the operation of controlling the AD converters 71a to 71e at regular intervals.

As shown in FIG. 15, when the logical product is 9 (Bit0=1, Bit1=0, Bit2=0, Bit3=1), the logic value of the signal S _INTE changes to 1 (see FIG. 15(j)). do. Note that the period of the signal S _INTE is a period T that is 16 times the period of the CLK signal. 15(a) to (i) are the same as those of FIGS. 10(a) to (i), so description thereof will be omitted.

Then, based on the logic value of the signal S _INTE changing to 1, the digital signal D _VE (conversion result data) (see FIG. 13) is output from the AD converter 71e.

The digital signal DVE is input to the serial signal converter _74e (see FIG. 13). The serial signal converter 74e converts the input digital signal D _VE into a serial signal S _VE (see FIG. 13). This processing is the same as the processing in the serial signal converters 74a to 74c described in the first embodiment, so detailed description will be omitted.

The serial signals S _VA to S _VE output from the serial signal converters 74 a to 74 e are also input to the serial signal selector 275 . The serial signal selector 275 selects an actually existing serial signal from among the serial signals S _VA to S _VE and outputs it as a serial signal S _E . That is, the serial signal selection unit 275 selects the serial signal S _VA (see FIG. 16(a)), the serial signal S _VB (see FIG. 16(b)), the serial signal S _VC (see FIG. 16) along the time axis. (c)), the serial signal S _VD (see FIG. 16(d)), and the serial signal S _VE (see FIG. 16(e)), the sum of the serial signal S _E (see FIG. 16(f)) output as The output timing control section 273 controls the output timings of the serial signals S _VA to S _VE so as not to overlap each other (see FIG. 16).

(Method for judging ground fault and DC overvoltage fault)
FIG. 17 is a circuit configuration diagram (equivalent circuit diagram) for explaining voltage and current states depending on the presence or absence of a ground fault. In FIG. 17, the current Ic flows through the portion of the power supply circuit portion 300a (see FIG. 13) of the state monitoring device 300 that is connected between the connection point A and the interconnection point M, and the connection point of the power supply circuit portion 300a It is shown that current Ie flows through the portion connected between B and interconnection point M. FIG. Note that the ground fault determination is the same as in the second embodiment, so the description is omitted.

As shown in FIGS. 17A to 17C, the voltage Vn2 across the resistance element 2b is expressed by the following equation (19) based on the resistance value R2n of the resistance element 2b and the current In2 flowing through the resistance element 2b. holds.

Also, the current In2 is calculated by the following equation (20) from the current In1 flowing through the resistance element 2a and the current Ie flowing through the resistance element 10.

Also, the current In1 is calculated from the resistance value R1n of the resistive element 2a and the voltage across the resistive element 2a (detected voltage at the connection point B) Vn1 by the following equation (21).

In addition, since the voltage across the resistance element 10 is the difference between the voltage Vn1 at the connection point B and the voltage Ve between the negative voltage feed section 8 and the resistance element 10, the current Ie is given by the following equation (22 ). Note that _Riee is the resistance value of the resistance element 10 .

Therefore, based on the above equations (18) to (22), the DC voltage En is calculated based on the following equation (23).

Based on the above equation (23), it is possible to determine the DC overvoltage failure of the diode converter 801d, which is the DC power supply on the negative side, when the negative voltage power supply unit 8 is arranged.

Other configurations of the third embodiment are the same as those of the second embodiment.

(Effect of the third embodiment)
The following effects can be obtained in the third embodiment.

In the third embodiment, as described above, the state signal output unit 27 outputs the current flowing through the resistance element group 1, the current flowing through the resistance element group 2, the current flowing between the connection point A and the positive voltage feeding unit 4, Also, the state monitoring device 300 is configured to output to the control device 900 a signal regarding the state of the power conversion device 801 based on the current flowing between the connection point B and the negative voltage power supply section 8 . As a result, the effect that a part of the current flowing through the resistance element group 2 is diverted toward the negative voltage feed section 8 is taken into account, so that each of the currents (detected values) flowing through the resistance element group 2 is , it is possible to suppress deviation from the value of the current actually flowing. As a result, when the negative voltage power supply unit 8 is provided, failure detection of the power conversion device 801 can be performed more accurately.

Further, in the third embodiment, as described above, the state signal output unit 27 controls the voltage Vp1 at the connection point A, the voltage Vn1 at the connection point B, and the current flowing between the connection point A and the positive voltage power supply unit 4. and a signal based on the voltage Ve between the resistive element 10 and the negative voltage feeder 8 to the control device 900 as a signal relating to the state of the power conversion device 801. Constitute. As a result, the current flowing between the connection point B and the negative voltage feeding section 8 can be easily calculated using the signal based on the voltage Ve output to the control device 900 . Moreover, since a signal based on the voltage Ve can be output to the control device 900 by providing the resistive element 10, a signal based on the voltage Ve can be output to the control device 900 with a relatively simple configuration.

Other effects of the third embodiment are the same as those of the second embodiment.

[Fourth Embodiment]
Next, the configuration of the condition monitoring device 400 according to the fourth embodiment will be described with reference to FIGS. 1, 18 and 19. FIG. Unlike the configuration of the state monitoring device 100 according to the first embodiment, the state monitoring device 400 of the fourth embodiment is configured such that the output timing control section 373 synchronizes with the upper control device 901 . In addition, the structure similar to the said 1st Embodiment attaches|subjects the same code|symbol as 1st Embodiment, and abbreviate|omits description while it is illustrated. Note that the control device 901 is an example of an "external control device" in the scope of claims.

(Configuration of condition monitoring device)
As shown in FIG. 18, in the fourth embodiment, state monitoring device 400 (see FIGS. 1 and 18) outputs signals based on each of voltage Vp1, voltage Vn1, and voltage Vc to indicate the state of power conversion device 800. The state signal output unit 37 is provided for outputting to the external control device 901 as a signal related to. Moreover, the state monitoring device 400 is provided with a power supply circuit portion 400 a including the state signal output section 37 .

The configuration and operation of the state signal output section 37 according to the fourth embodiment will be described in detail below.

(Configuration of status signal output section)
State signal output section 37 includes an O/E (Optical/Electrical) conversion section 370 and an output timing control section 373 . The O/E conversion unit 370 receives the optical signal _STL transmitted from the E/O conversion circuit 901 a of the control device 901 . The optical signal _STL is obtained by E/O-converting a pulse signal containing information on the timing at which the control device 901 starts calculation by the E/O conversion circuit 901a. The optical signal _STL from the E/O conversion circuit 901 a is transmitted to the O/E conversion section 370 via the optical cable 371 . The optical signal _STL is an example of the "pulse signal" in the claims.

The O/E converter 370 transmits the electrical signal _STE obtained by O/E converting the received optical signal _STL to the output timing controller 373 .

Here, in the fourth embodiment, the output timing control unit 373 synchronizes with the calculation of the control device 901 based on the optical signal _STL for starting the calculation from the control device 901, the AD converter 71a, the AD conversion A signal for controlling the output timing of the digital signal is transmitted to each of the device 71b and the AD converter 71c. A specific description will be given below.

As shown in FIG. 19, in the output timing control unit 373, the logical product is 15 until the electrical signal S _TE (see FIG. 19(α)) is input (while the electrical signal S _TE has a logical value of 0). (Bit0=1, Bit1=1, Bit2=1, Bit3=1). In other words, the AND is stopped at 15 until the electrical signal _STE is input.

Then, when the logical value of the electrical signal _STE becomes 1, the AND operation starts from 0. When the logical product becomes 15 by the addition operation, the logical product stops at 15 until the electrical signal _STE becomes 1 again. 19(a) to (h) are the same as FIGS. 4(a) to (h), so description thereof is omitted.

Then, the output timing control section 373 outputs the signal S _INTA , the signal S _INTB , and the signal S _INTC at the timing based on the electrical signal S _TE . It should be noted that the electrical signal _STE changes in logic value from 0 to 1 in the period _TCPU .

Other configurations of the fourth embodiment are the same as those of the first embodiment.

(Effect of the fourth embodiment)
The following effects can be obtained in the fourth embodiment.

In the fourth embodiment, as described above, the output timing control unit 373 synchronizes with the calculation of the control device 901 based on the optical signal _STL for starting the calculation from the control device 901, the AD converter 71a, Condition monitoring device 400 is configured to transmit a signal for controlling the output timing of the digital signal to each of AD converter 71b and AD converter 71c. Here, when the control device 901 and the state monitoring device 400 are not synchronized, in order to output digital signals from the conversion units (71a to 71c) within the calculation cycle of the control device 901, the calculation of the control device 901 It is necessary to make the operation of the state detection device sufficiently fast with respect to the period of . On the other hand, by synchronizing with the calculation of the control device 901, the operation of the condition monitoring device 400 can be made relatively slow. As a result, an increase in power consumption of state monitoring device 400 can be suppressed. In addition, since the current flowing in the state monitoring device 400 can be reduced by slowing down the operation, the resistance element in the state monitoring device 400 can be made smaller, and the heat generated in the resistance element can be reduced. A cooling system for dissipating heat can be miniaturized.

Also, in this case, since the amount of data transmitted within a predetermined period of time in the control device 901 is relatively small, the amount of memory provided in the control device 901 can be reduced. In addition, since the power consumption required for memory operations (writing and reading) can be reduced by reducing the amount of memory, the calculation load of the control device 901 can be reduced. In addition, since the amount of memory is reduced, the mounting area of the memory can be reduced, so that the controller 901 can be miniaturized.

Other effects of the fourth embodiment are the same as those of the first embodiment.

[Modification]
It should be noted that the embodiments disclosed this time should be considered as examples and not restrictive in all respects. The scope of the present invention is indicated by the scope of the claims rather than the description of the above-described embodiments, and includes all modifications (modifications) within the meaning and scope equivalent to the scope of the claims.

For example, in the above-described first to fourth embodiments, the fifth resistance element (resistance element 6) is arranged, and between the fifth resistance element (resistance element 6) and the first class current section (positive voltage feeding section 4) Although an example of calculating the current (Ic) flowing from the third voltage (voltage Vc) to the first-class power supply unit (positive voltage power supply unit 4) has been shown, the present invention is not limited to this. For example, a current sensor may be arranged in place of the fifth resistance element (resistance element 6) to directly detect the current (Ic) flowing through the first-class electrical section (positive voltage feeding section 4). .

Further, in the third embodiment, the eighth resistance element (resistance element 10) is arranged, and the fifth voltage drop between the eighth resistance element (resistance element 10) and the second class current section (negative voltage feeding section 8) is provided. Although an example of calculating the current (Ie) flowing through the second class current section (negative voltage power supply section 8) from the voltage (voltage Ve) has been shown, the present invention is not limited to this. For example, a current sensor may be arranged in place of the eighth resistance element (resistance element 10), and the current (Ie) flowing through the second-class current section (negative voltage power supply section 8) may be directly detected by the current sensor. .

Further, in the fourth embodiment, an example is shown in which the state monitoring device connected to the two-level inverter 800d is controlled so as to synchronize with the external control device (control device 901). Not limited. For example, the condition monitoring device connected to the three-level inverter 801f of the second and third embodiments may be controlled to synchronize with an external control device.
Further, in the first to fourth embodiments, an example in which the state monitoring device transmits signals to the external control devices (control devices 900 and 901) has been described, but the present invention is not limited to this. For example, the state monitoring device may be configured to transmit a signal to a CPU provided in the power electronics device.

1 resistance element group (first resistance element group)
1a resistive element (first resistive element)
1b resistance element (second resistance element)
2 resistance element group (second resistance element group)
2a resistive element (third resistive element)
2b resistance element (fourth resistance element)
3 Grounding resistance element (grounding resistance element part)
4 positive voltage feeder (first feeder)
6 resistance element (fifth resistance element)
7, 17, 27, 37 State signal output section 8 Negative voltage feeding section (second feeding section)
10 resistance element (eighth resistance element)
13 Ground resistance element group (ground resistance element part)
13a resistive element (sixth resistive element)
13b resistance element (seventh resistance element)
70a, 70b, 70c, 70d, 70e operational amplifier (predetermined circuit)
71a AD converter (predetermined circuit) (first conversion unit)
71b AD converter (predetermined circuit) (second conversion unit)
71c AD converter (predetermined circuit) (third conversion unit)
71d, 71e AD converter (predetermined circuit)
73, 173, 273, 373 Output timing control unit 100, 200, 300, 400 Condition monitoring device 800, 801 Power conversion device 800c Diode converter (DC power supply)
801c Diode converter (positive DC power supply) (DC power supply)
801d Diode converter (negative DC power supply) (DC power supply)
900, 901 control device (external control device)
A connection point (first connection point)
B connection point (second connection point)
C connection point (third connection point)
G ground point Ic current (current flowing between the first connection point and the first power supply)
Ie current (current flowing between the second connection point and the second feed)
In current (current flowing through the second resistance element group)
Ip1, Ip2 currents (currents flowing through the first resistance element group)
M interconnection point S _TL optical signal (pulse signal)
_SL optical serial signal (state-related signal)
Vc voltage (third voltage)
Ve voltage (fifth voltage)
Vg voltage (fourth voltage)
Vn1 voltage (second voltage)
Vp1 voltage (first voltage)

Claims (8)

A state monitoring device for monitoring the state of a power conversion device,
a first resistance element group connected to the positive side of the DC power supply of the power conversion device and including a first resistance element and a second resistance element connected in series with each other;
a second resistance element group connected between the negative side of the DC power supply and the first resistance element group and including a third resistance element and a fourth resistance element connected in series with each other;
a ground resistance element section connected between an interconnection point of the first resistance element group and the second resistance element group and a ground point;
a first power supply unit connected to a first connection point where the first resistance element and the second resistance element are connected, and supplying power to a predetermined circuit in the condition monitoring device;
a fifth resistance element or current sensor provided between the first connection point and the first power supply;
a signal relating to the state of the power conversion device based on the current flowing through the first resistance element group, the current flowing through the second resistance element group, and the current flowing between the first connection point and the first power supply unit; , and a state signal output unit for outputting to an external control device. The state signal output unit outputs a first voltage at the first connection point, a second voltage at the second connection point where the third resistance element and the fourth resistance element are connected, and the first connection point. 2. The apparatus according to claim 1, wherein a signal based on each of third voltages based on the current flowing between said first power supply unit is output to said external control device as a signal relating to said state. Condition monitor. The state signal output section is configured to output a signal based on the third voltage between the fifth resistance element and the first power supply section to the external control device as a signal relating to the state. 3. The condition monitoring device according to claim 2, wherein: The interconnection point is connected between a positive DC power supply of the power converter and a negative DC power supply of the power converter connected in series with the positive DC power supply,
the ground resistance element section includes a sixth resistance element and a seventh resistance element connected in series with each other;
The state signal output section outputs each of the first voltage, the second voltage, the third voltage, and a fourth voltage at a third connection point where the sixth resistance element and the seventh resistance element are connected. 4. The condition monitoring device according to claim 2, wherein a signal based on the condition is output to said external control device as a signal relating to said condition. each of the first voltage, the second voltage, and the third voltage is an analog value;
The state signal output section includes a first conversion section that converts the first voltage into a digital value, a second conversion section that converts the second voltage into a digital value, and a third conversion section that converts the third voltage into a digital value. 3 conversion units; and an output timing control unit that transmits a signal for controlling the timing of outputting the converted digital signal to each of the first conversion unit, the second conversion unit, and the third conversion unit. The condition monitoring device according to any one of claims 2 to 4, comprising: The output timing control section, based on a pulse signal for starting calculation from the external control device, synchronizes with the calculation of the external control device, the first conversion section, the second conversion section, and 6. The condition monitoring device according to claim 5, configured to transmit a signal for controlling output timing of said digital signal to each of said third converters. further comprising a second power supply unit connected to a second connection point where the third resistance element and the fourth resistance element are connected, and supplying power to the predetermined circuit;
The state signal output section outputs a current flowing through the first resistance element group, a current flowing through the second resistance element group, a current flowing between the first connection point and the first feeding section, and the second resistance element group. Any one of claims 1 to 6, configured to output a signal regarding the state of the power conversion device based on the current flowing between the connection point and the second power supply unit to the external control device. Condition monitoring device according to claim. further comprising an eighth resistive element provided between the second connection point and the second feeder;
The state signal output section has a first voltage at the first connection point, a second voltage at the second connection point, and a third voltage based on the current flowing between the first connection point and the first power supply section. , and a signal based on a fifth voltage between the eighth resistance element and the second power supply unit, as a signal relating to the state, to the external control device. Condition monitoring device as described.

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