JP2009247063A - Power conversion apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an arrangement capable of preventing the stop of driving of a converter circuit having a switching element as much as possible even if abnormal conditions occur in the converter circuit in a power conversion apparatus with the converter circuit. <P>SOLUTION: The converter circuit (2) includes a plurality of switching elements, and diodes each connected in parallel to each of the switching elements. A microcomputer (20) for converter which controls the operation of the converter circuit (2) includes an abnormal condition detecting section (24) constituted so as to be capable of detecting the abnormal conditions not causing stop of driving of the converter circuit (2) in the converter circuit (2), and a retry section (25) for performing retry operation for turning ON-OFF the switching elements when the abnormal condition detecting section (24) detects the abnormal conditions. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power converter, and more particularly to control of a converter circuit.

2. Description of the Related Art Conventionally, there has been known a power conversion device including a converter circuit that converts AC power of an AC power source into DC power and an inverter circuit that converts DC power of the converter circuit into AC power having a predetermined frequency. As such a power converter, for example, as disclosed in Patent Document 1, a plurality of diodes are connected in a bridge shape to form a converter circuit, and a plurality of switching elements are connected in a bridge shape to form an inverter. What constitutes a circuit is generally known. In this power converter, after the AC power of the AC power source is rectified into DC power by the converter circuit, the inverter circuit converts the AC power into AC power having a predetermined frequency.
JP 2004-222421 A

  By the way, when the converter circuit is configured with a diode as described above, current becomes difficult to flow when the potential difference acting on the diode becomes small, so that the current waveform on the AC side, which is ideally sinusoidal, is distorted. There is a problem of causing harmonic generation.

  On the other hand, in the converter circuit, it is conceivable to use a switching element instead of a diode to control the operation of the switching element. By doing so, the current waveform flowing on the AC side (power supply side) of the converter circuit can be brought close to a sine wave, and the generation of harmonics can be suppressed as much as possible.

  However, when the converter circuit is configured by a plurality of switching elements in this way, the configuration of the converter circuit becomes complicated, and accordingly, an abnormality is likely to occur.

  On the other hand, in the conventional configuration using the diode bridge as described above, usually only a control microcomputer is provided on the inverter circuit side. In view of the above, the entire apparatus is immediately stopped.

  Therefore, as described above, if the converter circuit is configured with switching elements, the configuration of the converter circuit becomes complicated and an abnormality is likely to occur. Therefore, as with the inverter circuit, any abnormality occurs immediately. If the configuration is such that the drive of the entire apparatus is stopped, the frequency of the stop is higher than in the conventional configuration, which makes the user feel uncomfortable. For example, in the case of an air conditioner, the compressor is stopped, which causes a problem that the capacity of the air conditioner becomes insufficient.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a converter circuit having a converter circuit having a switching element, even if an abnormality occurs in the converter circuit. Is to obtain a configuration that does not stop driving as much as possible.

  In order to achieve the above object, in the power conversion device (1) according to the present invention, the converter control means (20) for controlling the operation of the converter circuit (2) in which a switching element and a diode are connected in parallel includes When a malfunction in the converter circuit (2) is detected, the system is equipped with a retry control means (25) that performs a retry operation by turning the switching element on and off, enabling recovery while continuing operation. I made it possible to run continuously as much as possible.

  Specifically, the first invention is directed to a power conversion device including a converter circuit (2) connected to an AC power source (5) and converting AC power into DC power.

  The converter circuit (2) has a plurality of switching elements and diodes connected in parallel to the switching elements, and converter control means (20 for controlling the operation of the converter circuit (2) The converter control means (20) includes an abnormality detector (24) configured to be able to detect an abnormality that does not cause the circuit (2) to stop driving in the converter circuit (2). And a retry control unit (25) that performs a retry operation by causing the switching element to perform an ON-OFF operation when the abnormality is detected by the abnormality detection unit (24).

  With the above configuration, the converter circuit (2) has a plurality of switching elements and diodes connected in parallel to the respective switching elements. Therefore, even if the switching elements are turned off, the diode functions as a rectifier circuit. Can be maintained. Therefore, when the abnormality detection unit (24) detects an abnormality in the converter circuit (2) and the retry control unit (25) causes the switching element to perform an ON-OFF operation, the switching element is Since current flows to the diode side even in the OFF state, it is not necessary to stop driving the entire apparatus. As a result, the drive stop of the inverter circuit (3) due to the occurrence of an abnormality on the converter circuit (2) side can be reduced as much as possible. be able to.

  In addition, by providing a retry controller (25) that performs the retry operation of the switching element, self-repair is possible depending on the degree of abnormality of the converter circuit (2). Is no longer required and continuous operation is possible.

  In the above configuration, when the abnormality is detected by the abnormality detection unit (24), the retry control unit (25) temporarily turns off the switching element and then turns the switching element at a predetermined interval. It is preferable to perform an ON-OFF operation (second invention).

  In this manner, when an abnormality occurs in the converter circuit (2), normalization of the converter circuit (2) can be promoted by operating the switching elements at ON-OFF intervals at predetermined intervals. As described above, since the current flows to the diode side while the switching element is in the OFF state, harmonics are generated as in the case of a bridge circuit using a conventional diode. Therefore, the predetermined interval is set within a range where the influence of the harmonic output is small.

  The converter control means (20) includes an output detection unit (26) for detecting an output of the converter circuit (2), and an output detected by the output detection unit (26) is continuously desired for a predetermined time. And an output determination unit (27) that determines whether or not the output of the converter circuit matches the output of the converter circuit. The retry control unit (25) is continuously operated by the output determination unit (27) for a predetermined time or more. When it is determined that the output of (2) matches the desired output, the retry operation is preferably stopped and returned to the normal operation (third invention).

  Thereby, it is possible to prevent the retry operation from being performed wastefully when the converter circuit (2) returns to normal. That is, when the output from the converter circuit (2) has returned to normal for a predetermined time or longer, it is determined that the abnormality of the converter circuit (2) has been resolved, and the retry control unit (25) By terminating the retry operation by the step and returning to the normal operation operation, the converter circuit (2) can be driven efficiently. Further, in this way, by terminating the retry operation and returning to the normal operation as it is, the converter circuit (2) can be continuously driven without stopping the drive of the converter circuit (2). it can.

  As described above, according to the power converter (1) of the present invention, in the converter circuit (2), the diode is provided in parallel with the switching element, and the converter control means (20) is provided in the converter circuit (2). When an abnormality that does not cause the drive to stop is detected, the switching circuit is configured to have a retry control unit (25) that performs an ON-OFF operation to perform a retry operation. Even if it occurs, the device (1) can be operated continuously as much as possible, and it is possible to prevent the user from feeling uncomfortable by stopping the device as much as possible.

  Further, according to the second invention, the retry control unit (25) is configured to turn the switching element OFF after the abnormality occurs, and then turn the switching element ON-OFF at a predetermined interval. Therefore, it is possible to return the operation of the converter circuit (2) to normal by repeatedly performing a retry operation without stopping the operation of the device (1).

  Further, according to the third invention, the retry control unit (25) performs the retry operation when the output of the converter circuit (2) continuously matches the desired output for a predetermined time or more. Since it is configured to stop and return to the normal operation, the converter circuit (2) can be driven efficiently without wasteful retry operation.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

<overall structure>
Embodiments of the present invention are described below. As shown in FIG. 1, the power converter device (1) according to the present embodiment includes a converter circuit (2), an inverter circuit (3), and a capacitor circuit (4). The converter circuit (2) has an input side connected to a commercial power supply (5) for supplying AC power, and an output side connected in parallel with the capacitor circuit (4) and the inverter circuit (3). Yes. Further, for example, an electric motor (motor) (6) of a compressor of an air conditioner is connected to the inverter circuit (3).

  The converter circuit (2) is for converting three-phase AC power output from the commercial power source (5) into DC power, and is configured as a so-called rectifier circuit. In general, the converter circuit (2) is configured by a diode bridge circuit. In this embodiment, a switching element such as an IGBT (insulated gate bipolar transistor) is three-phased to reduce harmonics. It is configured by bridge connection. In the present embodiment, a diode is connected in parallel with the switching element. Thus, by connecting the diode in parallel with the switching element, as described later, it becomes possible to retry the switching element in the converter circuit (2) without stopping the drive of the inverter circuit (3). Thus, it is possible to reduce the frequency of drive stop of the inverter circuit (3) when an abnormality occurs in the converter circuit (2). In FIG. 1, the diode is connected in antiparallel with the switching element. However, the present invention is not limited to this, and the connection direction of the diode may be either. In FIG. 1, the description of the bridge circuit of the switching element is omitted for the sake of simplicity.

  Further, as shown in FIG. 1, a reactor (7, 7, 7) is provided for each phase between the converter circuit (2) and the commercial power source (5). Further, a zero-cross detection circuit (11) described later (Z / C in FIG. 1) is provided between the commercial power source (5) and the reactor (7, 7, 7) so as to straddle two of the three phases. Is provided.

Further, a DCCT (8, 8) for detecting a current i ₁ of two phases out of the three phases is provided between the reactor (7, 7) and the converter circuit (2). The current of each phase detected by the DCCT (8, 8) is converted into a corresponding signal and then transmitted to the converter microcomputer (10), which will be described later, to control the drive of the switching element in the converter circuit (2). It is used as one of the parameters.

  The capacitor circuit (4) has two capacitors (4a, 4b) connected in series, and is connected in parallel to the converter circuit (2) and the inverter circuit (3). The capacitor circuit (4) is configured to be able to charge and discharge the DC power converted by the converter circuit (2), and to supply DC power to the inverter circuit (3) by discharging the DC power. belongs to.

  The inverter circuit (3) is for converting DC power discharged from the capacitor circuit (4) into AC power. Specifically, the inverter circuit (3) includes a plurality of switching elements connected in a three-phase bridge, and a DC voltage discharged from the capacitor circuit (4) is required for the motor (6). It is comprised so that it may convert into the alternating voltage of the frequency. The switching element used in the inverter circuit (3) is also a switching element such as an IGBT, for example, like the converter circuit (2). In FIG. Description of the configuration of is omitted.

In addition, two resistors (9, 9) connected in series between the capacitor circuit (4) and the inverter circuit (3) are connected to the capacitor circuit (4) and the inverter circuit (3). Connected in parallel. Intermediate voltage e _d of the resistors (9, 9) is detected by a voltage sensor that measures the DC voltage (not shown) is converted into a corresponding signal, the converter microcomputer (20) to be described later and the inverter Microcomputer (30), overvoltage detection means (12) (OVP in FIG. 1), etc.

Further, the power converter (1) includes a shunt resistor (10a) for detecting current by a current sensor (not shown) on the output side of the converter circuit (2) and the input side of the inverter circuit (3). 10b). Current i _d measured by the shunt resistor (10a) provided on the output side of the converter circuit (2) is converted to a corresponding signal, described later converter microcomputer (20) and over-current detection means ( 13) (OCP in Fig. 1) On the other hand, the current i ₂ measured by the shunt resistor (10b) provided on the input side of the inverter circuit (3) is converted into a corresponding signal, and then the inverter microcomputer (30) and overcurrent detection described later. Sent to the means (14).

  The overcurrent detection means (13, 14) is configured to be able to detect an overcurrent state. When the overcurrent state is detected, switching is performed for the converter circuit (2) and the inverter circuit (3), respectively. A compulsory signal for stopping the driving of the element is output.

  The power converter (1) is provided with a zero cross detection circuit (11) on the input side connected to the commercial power source (5). This zero cross detection circuit (11) is provided so as to straddle two of the three phases, and is configured to detect the zero cross point of the input voltage by detecting the voltage difference between the two phases. It is. Based on the zero cross point of the input voltage detected by the zero cross detection circuit (11), the switching element of the converter circuit (2) is driven and controlled.

<Microcomputer configuration>
The power conversion device (1) having the circuit configuration as described above includes a converter microcomputer (20) (converter control means) for performing drive control of the switching element of the converter circuit (2), and the inverter circuit (3 ) Inverter microcomputer (30) for controlling the drive of switching elements, and a control microcomputer (40) for transmitting operation control signals for the entire power converter (1) to these microcomputers (20, 30) It has.

The converter microcomputer (20) includes a zero-cross point detected by the zero-cross detection circuit (11), a current value i ₁ on the input side detected by the DCCT (8), and a current sensor by the shunt resistor (10a). based current value i _d of the detected output _side, in such a voltage value e _d detected between the resistors (9, 9) by, configured to control the driving of the switching elements of the converter circuit (2) Has been. That is, the converter microcomputer (20) generates a drive signal for the switching element based on the zero cross point, the input side and output side current values, voltage values, etc., and outputs the drive signal generation unit (21). I have.

  The converter microcomputer (20) is configured to detect an overcurrent based on a direct current measured by a shunt resistor (10a) provided on the output side of the converter circuit (2). . That is, the direct current measured by the shunt resistor (10a) is detected as an overcurrent by the overcurrent detection means (13) and detected as an overcurrent by the overcurrent detection means (13). In this case, a drive stop forcing signal is sent from the overcurrent detection means (13) to the switching element of the converter circuit (2). Then, the converter microcomputer (20) detects that the switching element of the converter circuit (2) is not driven, and thereby recognizes that the converter microcomputer (20) is in an overcurrent state. Is done.

Further, the converter microcomputer (20), an overvoltage condition is detected on the basis of the voltage e _d between the resistors being measured (9,9) by a voltage sensor (not shown), it is inputted as a signal It is configured as follows. That is, the voltage e _d measured by the voltage sensor is inputted to the over-voltage detection means (12), an overvoltage condition is detected by the overvoltage detector (12). When the overvoltage state is detected by the overvoltage detection means (12), an overvoltage signal is transmitted to the converter microcomputer (20), and the converter microcomputer (20) detects the overvoltage.

  Further, the converter microcomputer (20) includes an abnormality detection unit (24) for detecting an abnormality occurring in the converter circuit (2), and the degree of abnormality detected by the abnormality detection unit (24). A warning signal generation unit (22) and an abnormal signal generation unit (23) for generating a signal in response thereto are provided.

  The abnormality detection unit (24) outputs signals output from the DCCT (8), current sensor, voltage sensor, zero-cross detection circuit (11), overvoltage detection means (12), overcurrent detection means (13), etc. Based on this, it is configured to detect an abnormality in the converter circuit (2). The abnormality detected by the abnormality detector (24) is a minor one that does not require stopping the drive of the converter circuit (2) and a serious one that needs to stop the drive of the converter circuit (2). In general, it is classified into two categories. Therefore, the abnormality detection unit (24) provides a warning signal to the warning signal generation unit (22) in the case of a minor abnormality (light abnormality) that does not require stopping the drive of the converter circuit (2). Instructs the generation of an abnormal signal to the abnormal signal generator (23) in the case of a serious abnormality (major abnormality) that requires stopping the drive of the converter circuit (2) while instructing the generation of the signal It is configured as follows.

Specifically, the abnormality detection unit (24), the DCCT (8) or the shunt resistor, such as a current sensor provided in (10a) abnormal overvoltage condition, the voltage e _d between the resistors (9, 9) In the case of detecting an abnormality in the voltage sensor for detecting the current, the instantaneous overcurrent state detected through the operation of the overcurrent detection means (13), the synchronization failure of the switching element with respect to the power supply frequency, etc., the converter circuit ( Since there is no need to stop the driving in 2), the warning signal generation unit (22) is instructed to generate a warning signal.

  On the other hand, the abnormality detection unit (24) performs switching when a reverse phase / open phase of the input voltage is detected based on the detection data of the zero cross detection circuit (11), or when an abnormality of the zero cross signal is detected. When an element abnormality is detected, it is necessary to stop the drive of the converter circuit (2), so the abnormality signal generation unit (23) is instructed to generate an abnormality signal.

  When the abnormality detection unit (24) detects an abnormality that does not require the drive of the converter circuit (2) and the inverter circuit (3) to be completely stopped. In addition, it is configured to generate a warning signal.

  As will be described in detail later, the converter microcomputer (20) resets the operation of the switching element in the converter circuit (2) when the warning signal is generated by the warning signal generator (22). Thus, a retry operation for re-operation is performed. However, this retry operation is also stopped while an abnormal signal is output as will be described later.

  The abnormality signal generation unit (23) generates an abnormality when the abnormality detection unit (24) detects an abnormality that needs to stop driving the converter circuit (2) and the inverter circuit (3). It is configured to generate a signal.

  The converter microcomputer (20) is connected to the inverter microcomputer (30) through a plurality of ports, and is used in the warning signal generation unit (22) and the abnormal signal generation unit (23). When a signal is generated, the signal is transmitted to the inverter microcomputer (30) via a dedicated port for each signal. Further, the converter microcomputer (20) transmits a waveform output state signal indicating the state of the output waveform from the converter circuit (2) to the inverter microcomputer (30) via a dedicated port, An operation permission signal (a signal relating to whether the converter circuit (2) can be driven) is received from the inverter microcomputer (30) via a dedicated port.

  The inverter microcomputer (30) includes an output of a voltage sensor (not shown) for detecting a voltage between the resistors (9, 9), an output of a current sensor (not shown) at the shunt resistor (10b), the converter The switching element of the inverter circuit (3) is driven and controlled based on the waveform output state signal transmitted from the microcomputer (20). That is, the inverter microcomputer (30) includes a drive signal generation unit (31) that generates a drive signal for the switching element based on detected values of voltage and current.

  The inverter microcomputer (30) includes an abnormal signal generator (32) that generates an abnormal signal when an abnormality occurs in the inverter circuit (3). The abnormal signal generation unit (32) generates an abnormal signal when, for example, the switching element in the inverter circuit (3) is abnormal or an overcurrent is detected by the overcurrent detection means (14). It is configured. Since the inverter circuit (3) stops driving immediately when an abnormality occurs, the inverter microcomputer (30) generates a warning signal like the converter microcomputer (20) described above. Part (22) does not exist.

  Further, the inverter microcomputer (30) includes a flag generator (33) that generates an abnormality flag or a warning flag based on a warning signal or an abnormality signal transmitted from the converter microcomputer (20), and A code generator (34) that generates an abnormal code or a warning code based on a warning signal or an abnormal signal, and a standby request that generates a standby request signal based on the abnormal code generated by the code generator (34) A signal generator (35) is provided.

  Specifically, the flag generating unit (33) sets the abnormality flag to 1 when an abnormal signal is transmitted from the converter microcomputer (20), while the warning signal is output from the converter microcomputer (20). Is transmitted, the warning flag is set to 1. The code generator (34) generates a signal corresponding to the abnormal code when an abnormal signal is transmitted from the converter microcomputer (20), while a warning signal is received from the converter microcomputer (20). A signal corresponding to the warning code is generated when transmitted. The standby request signal generator (35) is configured to generate a standby request signal only when a signal corresponding to the abnormal code is generated by the code generator (34).

  The inverter microcomputer (30) is configured to be capable of mutual communication with the control microcomputer (40), and the control microcomputer (40) receives signals corresponding to the codes and flags and a standby request signal. It is configured to be able to send to. Further, the inverter microcomputer (30) receives an abnormal reception completion signal output from the control microcomputer (40) when the control microcomputer (40) receives a standby request signal, or the control microcomputer (40). ) To receive an operation control signal such as an operation stop signal. The inverter microcomputer (30) and the control microcomputer (40) are connected so as to be able to exchange signals by serial communication or parallel communication.

  The control microcomputer (40) is for controlling the operation of the power converter (1). The inverter microcomputer (30) drives the converter circuit (2) and the inverter circuit (3). An operation control signal for controlling is output. In addition, as described above, the control microcomputer (40) completes abnormal reception when receiving a warning signal signal, a code signal corresponding to the abnormal signal, a flag signal, a standby request signal, etc. from the inverter microcomputer (30). A signal is output, and an operation stop signal is output when a standby request signal is received.

  The inverter microcomputer (30) is configured to store information such as an operating state as a history together with these signals when a warning signal or an abnormality signal is received from the converter microcomputer (20). In addition, when the control microcomputer (40) receives signals corresponding to the flags and codes from the inverter microcomputer (30), the control microcomputer (40) is configured to store them as a history. With these configurations, when the operator identifies the cause of the abnormality, the history information stored in the inverter microcomputer (30) and the control microcomputer (40) can be used.

<Configuration of retry control unit, etc.>
The converter microcomputer (20) performs an ON-OFF operation on the switching element in the converter circuit (2) when an abnormality corresponding to the above warning signal occurs in the converter circuit (2). A retry control unit (25) for performing (retry operation) is provided. When the abnormality detection unit (24) detects an abnormality corresponding to the warning signal, the retry control unit (25) temporarily turns off the switching element and then performs an ON-OFF operation at a predetermined interval. Is configured to be repeatedly performed. In this way, while the switching element is in the OFF state, a current flows through a diode provided in parallel to the switching element, and harmonics are generated. Therefore, the switching element is turned on. The predetermined interval is set such that generation of harmonics is not a problem.

  The converter microcomputer (20) receives signals transmitted from the current sensor and voltage sensor (not shown) on the output side of the converter circuit (2), and receives the current value on the output side of the converter circuit (2). And the output detector (26) that detects the voltage value as the output of the converter circuit (2), and the output (current value, voltage value) detected by the output detector (26) and the microcomputer (20) predicts An output determination unit (27) for determining whether or not the desired output matches.

  The output determination unit (27) determines whether the output values match as described above, and the time during which the output detected by the output detection unit (26) matches the desired output is a predetermined time. As described above, it is also configured to determine whether or not it is continuing. Here, when the output determination unit (27) determines that the outputs match, the converter circuit (2) is in a normal operating state, and therefore the matching time is predetermined. If it continues for more than the time, it is determined that the abnormal factor of the converter circuit (2) has been eliminated. The predetermined time is set to a time at which it can be determined that the abnormality factor of the circuit (2) has been eliminated based on the output of the converter circuit (2).

  When the retry control unit (25) determines that the output determination unit (27) continuously matches the output of the converter circuit (2) for a predetermined time or more, It is configured to cancel the retry operation. In other words, if the output of the converter circuit (2) is not consistent with the output predicted by the output determination unit (27) for a predetermined time or longer, the retry control unit (25) It is configured to continue the retry operation until it coincides continuously for a time or more.

-Driving action-
Hereinafter, operations of the converter microcomputer (20) and the inverter microcomputer (30) when an abnormality occurs in the converter circuit (2) will be described. First, warning signal processing and abnormal signal processing in each microcomputer (20, 30) will be described first, and then the retry operation of the converter microcomputer (20), which is a feature of the present invention, will be described.

<Operation of inverter microcomputer when an error occurs>
(Processing when an abnormality equivalent to a warning signal occurs)
FIG. 2 is a time chart showing the state of processing in the inverter microcomputer (30) when an abnormality corresponding to the warning signal occurs in the converter circuit (2) in the power conversion device (1) configured as described above. It is the figure typically shown by.

  As shown in FIG. 2, when an abnormality corresponding to the warning signal occurs in the converter circuit (2) at t1 (there is a warning factor in the figure), the converter microcomputer (20) generates a warning signal. A warning signal is generated in the section (22) and output to the inverter microcomputer (30) through a dedicated port. Then, in the microcomputer for inverter (30), the warning flag is changed to 1 by the flag generator (33), and a signal corresponding to the warning code is generated by the code generator (34), and the control microcomputer (40) ).

  When the control microcomputer (40) receives these warning code and warning flag, it transmits an abnormal reception completion signal to the inverter microcomputer (30). When the inverter microcomputer (30) receives an abnormal reception completion signal, it sets the abnormal reception completion flag to 1 and returns it to zero again.

  Even when the inverter microcomputer (30) receives the abnormal reception completion signal, the inverter circuit (2) does not receive a warning signal signal at t2 until there is no factor corresponding to the warning signal (t2). ), The warning flag and the warning code are not cleared.

<Processing when an abnormality equivalent to an abnormal signal occurs>
FIG. 3 is a diagram schematically showing a state of processing in the inverter microcomputer (30) when an abnormality corresponding to an abnormality signal occurs in the converter circuit (2) in a time chart.

  As shown in FIG. 3, when an abnormality corresponding to an abnormal signal occurs in the converter circuit (2) at t1, an abnormal signal is generated by the abnormal signal generator (23) of the converter microcomputer (20). The abnormal signal is transmitted to the inverter microcomputer (30) through a dedicated port. Then, the flag generation unit (33) of the inverter microcomputer (30) changes the abnormality flag to 1, and the code generation unit (34) generates a signal corresponding to the abnormality code. In response to this, a standby request signal is generated by the standby request signal generator (35), and signals and standby request signals corresponding to these flags and codes are transmitted to the control microcomputer (40). Thereby, an operation stop signal is transmitted from the control microcomputer (40) to the inverter microcomputer (30), and the drive in the converter circuit (2) and the inverter circuit (3) is stopped. When the abnormality factor disappears at t2, the flag generation unit (33) changes the abnormality flag to zero, and the code generation unit (34) stops generating the signal corresponding to the abnormal code, and waits for a request for waiting. The generation of the standby request signal in the signal generator (35) is also stopped.

-Retry operation-
FIG. 4 is a time chart schematically showing the retry operation in the converter microcomputer (20) when an abnormality occurs in the converter circuit (2) and the warning signal is generated.

  As shown in FIG. 4, when an abnormality equivalent to the warning signal occurs in the converter circuit (2) at T1, the abnormality detection unit (24) detects the abnormality and enters an abnormal code state. Then, a warning signal generation unit (22) generates a warning signal (the warning signal output is HIGH in the figure). The abnormal code is used to display the occurrence of an abnormality, and after a certain amount of time has elapsed after temporarily entering an abnormal code state, the abnormal code returns to a state without an abnormal code.

  As described above, when an abnormality is detected by the abnormality detection unit (24), a retry operation is started by the retry control unit (25). Specifically, in order to temporarily turn off the switching element in the converter circuit (2), the switching element is turned off from the retry control unit (25) to the drive signal generation unit (21). Is output.

  Thereafter, at a predetermined interval after the switching element is turned off, a signal for turning on the switching element is output from the retry control unit (25) to the drive signal generation unit (21) at T2. . While operating the switching element, the output detection unit (25) detects the current value or voltage value on the output side of the converter circuit (2), and the output determination unit (26) detects the converter circuit (2). It is determined whether or not the output is consistent with the desired output expected by the operation of the switching element and the matching period continues for a predetermined time (30 seconds in the example of FIG. 4). In the example of FIG. 4, it is determined by the output determination unit (26) that output coincidence has not continued for a predetermined time or more, and the retry control unit (25) to the drive signal generation unit (21) at T3. Thus, a signal for turning off the switching element is output.

  In the retry operation at T2 and T3, the output determination unit (26) determines that the output of the converter circuit (2) continuously matches the desired output expected by the operation of the switching element for a predetermined time. (In the example of FIG. 4, the same operation as T2 is performed at T4 and T6, and the same operation as T3 is performed at T5). In the example of FIG. 4 described above, another abnormality occurs in the converter circuit (2) at T3 and T5, and the switching element is controlled to be turned OFF at that timing.

  In this way, the switching element is retried repeatedly, and the output determination unit (26) determines that the output of the converter circuit (2) continuously matches the desired output for a predetermined time ( In FIG. 4, it is determined that the abnormality factor in the converter circuit (2) has been resolved and the normal state of the operation ((7) is canceled by the retry control unit (25) being stopped. Return to the operation control to achieve the required output waveform. Also, the generation of the warning signal by the warning signal generation unit (22) is stopped (in the figure, the warning signal output is LOW).

-Effect of the embodiment-
As described above, according to this embodiment, the converter circuit (2) having a plurality of switching elements is provided with the diode in parallel with the switching elements, and drives and controls the converter circuit (2). The converter microcomputer (20) includes a retry control unit (25) that performs a retry operation of the switching element when an abnormality occurs to the extent that the converter circuit (2) does not have to stop driving. Therefore, the switching element can be retried without stopping the driving of the converter circuit (2) and the inverter circuit (3). Therefore, with the above configuration, even if a minor abnormality occurs in the converter circuit (2), the abnormality factor can be resolved by itself without stopping the drive of the converter circuit (2) and the inverter circuit (3). Thus, it is possible to return to the normal operation. Therefore, it is possible to prevent the user from feeling uncomfortable by stopping the power conversion device (1) accompanying the occurrence of a minor abnormality in the converter circuit (2).

  In addition, the retry operation by the retry control unit (25) is performed at a predetermined interval that is less affected by the generation of harmonics after the switching element is turned off, so that a current flows through the diode when the switching element is turned off. The generation of harmonics during the operation can be suppressed as much as possible, and the influence of the harmonics during the retry operation can be reduced as much as possible.

  Further, the retry control unit (25) continuously matches the output from the converter circuit (2) during the retry operation with a desired output expected when the switching element is operated for a predetermined time or more. In this case, the retry operation is stopped and the normal operation operation is resumed. Therefore, it is surely and quickly detected that the cause of the abnormality in the converter circuit (2) has been eliminated, and the normal operation is quickly performed. Return to driving. Therefore, with the above-described configuration, the converter circuit (2) can be driven as efficiently as possible.

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About the said embodiment, it is good also as following structures.

  In the above embodiment, the IGBT is used as the switching element constituting the converter circuit (2) and the inverter circuit (3). However, the present invention is not limited to this. For example, a switching element having another configuration such as a MOS-FET may be used. Good.

  Moreover, in the said embodiment, although the power converter device (1) divides the abnormality which generate | occur | produces in a converter circuit (2) into two steps, it is comprised so that a warning signal or an abnormal signal may be output, Not limited to this, the signal may be output in three or more stages. Even in this case, when the converter circuit (2) can be driven, the retry operation as in the present invention may be performed.

  As described above, the present invention is particularly useful for a power conversion device including a converter circuit having a plurality of switching elements.

It is a circuit diagram showing a schematic structure of a power converter concerning an embodiment of the present invention. It is a time chart which shows the process in the microcomputer for inverters when the warning signal is output from the microcomputer for converters. It is a time chart which shows the process in the microcomputer for inverters when the abnormal signal is output from the microcomputer for converters. It is a time chart which shows the retry operation in the microcomputer for converters.

Explanation of symbols

1 Power Converter 2 Converter Circuit 3 Inverter Circuit 4 Capacitor Circuit 5 Commercial Power Supply (AC Power Supply)
6 Electric motor 7 Reactor 8 DCCT
DESCRIPTION OF SYMBOLS 9 Resistance 10a, 10b Shunt resistance 11 Zero cross detection circuit 12 Overvoltage detection means 13 Overcurrent detection means 14 Overcurrent detection means 20 Microcomputer for converters (converter control means)
DESCRIPTION OF SYMBOLS 21 Drive signal generation part 22 Warning signal generation part 23 Abnormal signal generation part 24 Abnormality detection part 25 Retry control part 26 Output detection part 27 Output determination part 30 Microcomputer for inverter 31 Drive signal generation part 32 Abnormal signal generation part 33 Flag generation part 34 Code generator 35 Standby request signal generator 40 Control microcomputer

Claims (3)

A power conversion device including a converter circuit (2) connected to an AC power source (5) and converting AC power into DC power,
The converter circuit (2) includes a plurality of switching elements and diodes connected in parallel to the switching elements,
Converter control means (20) for controlling the operation of the converter circuit (2),
The converter control means (20)
An abnormality detection unit (24) configured to be able to detect an abnormality that does not involve stopping the driving of the circuit (2) in the converter circuit (2);
And a retry control unit (25) for performing a retry operation by causing the switching element to perform an ON-OFF operation when the abnormality is detected by the abnormality detection unit (24). apparatus. In claim 1,
When the abnormality is detected by the abnormality detection unit (24), the retry control unit (25) temporarily turns off the switching element, and then turns the switching element on and off at a predetermined interval. The power converter characterized by the above-mentioned. In claim 1 or 2,
The converter control means (20)
An output detector (26) for detecting the output of the converter circuit (2);
An output determination unit (27) that determines whether the output detected by the output detection unit (26) continuously matches a desired output for a predetermined time; and
The retry control unit (25), when it is determined by the output determination unit (27) that the output of the converter circuit (2) continuously matches a desired output for a predetermined time or more, A power converter configured to stop a retry operation and return to a normal operation.

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