JP2014165956A - Rotary electric machine drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve, in a smaller-scaled circuit, a function for detecting an overcurrent caused by a grounding fault or the like of an inverter circuit.SOLUTION: Between an upper-stage side arm and a high voltage DC positive pole line P, a current detection circuit 6 is provided for detecting a current which flows through at least one upper-stage side arm. An upper-stage drive circuit 7U for driving a switching element 3U of the upper-stage side arm is operated by a bootstrap power source 70 with a potential at the negative pole side of the upper-stage side arm as a negative pole and with a potential increased by a predetermined voltage as a positive pole with respect to the negative pole. The current detection circuit 6 is operated by power supply for a detection circuit generated by a power supply circuit 63 for a detection circuit including a bootstrap circuit utilizing the bootstrap power source 70.

Description

  The present invention relates to a rotating electrical machine drive device that drives and controls an AC rotating electrical machine.

  In many cases, a rotating electrical machine drive apparatus that drives and controls an AC rotating electrical machine is provided with an inverter circuit that performs power conversion between direct current and alternating current. The inverter circuit is often configured using a semiconductor switching element. If an overcurrent flows through these semiconductor switching elements due to contact between the inverter circuit housing case and the inverter circuit, the elements are destroyed and the life is deteriorated. For this reason, a circuit protection mechanism that detects an overcurrent and interrupts the supply of power to the inverter circuit may be provided. Japanese Patent Laying-Open No. 2006-187101 (Patent Document 1) discloses a technique related to a method for driving an inverter circuit including such a protection circuit.

  The inverter circuit of Patent Document 1 is configured using an IGBT (insulated gate bipolar transistor) having a current sense terminal for current detection in addition to the emitter terminal. A shunt resistor is connected in series to the current sense terminal, and an overcurrent detection circuit including a comparator for determining a terminal voltage of the shunt resistor is provided. This overcurrent detection circuit is operated by a power source of a drive circuit that drives an IGBT having a current sense terminal connected to the overcurrent circuit (FIG. 1 of Patent Document 1).

  Such an overcurrent detection circuit is connected to the current sense terminal of the IGBT. Therefore, an inverter circuit using an IGBT or power transistor that does not have a current sense terminal cannot adopt this circuit configuration. For example, an inverter circuit that converts power between three-phase alternating current and direct current requires three overcurrent detection circuits even on the upper stage side only. For example, in the detection of overcurrent due to a ground fault or the like where the positive electrode side of the DC contacts the case, it is not necessary to monitor the three phases independently, and the overcurrent detection circuit may be integrated into one. However, since the shunt resistor for detecting the current is arranged between the upper-stage IGBT and the lower-stage IGBT, the three-phase shunt resistors cannot be combined into one, and the circuit scale is reduced. Has its limits.

JP 2006-187101 A

  In view of the above background, a technique for realizing a function of detecting an overcurrent due to a ground fault or the like with a smaller circuit is desired.

According to the present invention in view of the above problems, the characteristic configuration of the rotating electrical machine drive device for driving and controlling an AC rotating electrical machine is as follows:
An upper arm provided between a high-voltage DC power supply and the rotating electrical machine, which performs power conversion between DC and a plurality of phases of AC, and includes a switching element and is connected to the high-voltage DC positive line side And an inverter constituted by a bridge circuit in which a complementary arm in which a switching element is provided and a lower arm connected to the high-voltage DC negative line side is connected in series is connected in parallel for the number of phases of a plurality of phases Circuit,
An inverter control unit that operates by power supplied from a low-voltage DC power supply having a voltage lower than that of the high-voltage DC power supply, generates a control signal for the switching element, and controls the inverter circuit;
A drive circuit for driving the switching element in response to the control signal,
Furthermore, a current detection circuit for detecting a current flowing through the at least one upper arm is provided between the upper arm and the high-voltage DC positive line,
Of the drive circuits, the upper drive circuit that drives the switching element of the upper arm has a negative potential on the negative side of the upper arm and is increased by a predetermined voltage with respect to the negative electrode. Operated by a bootstrap power supply with a positive potential,
The current detection circuit is operated by a detection circuit power supply generated by a detection circuit power supply circuit having a bootstrap circuit using the bootstrap power supply.

  When performing switching control of an inverter that converts electric power between direct current on the high-voltage direct-current power supply side and alternating current on the rotating electrical machine side by a control signal generated by an inverter control unit that uses a low-voltage direct-current power supply as a voltage source, the control signal is Often relayed through a drive circuit. In other words, the control signal generated by the low-voltage system circuit does not have sufficient drive capability to drive the switching element of the inverter circuit of the high-voltage system circuit. Therefore, the drive circuit can drive the switching element constituting the inverter circuit. Capability is added (such as voltage amplitude expansion and input / output current supply). Therefore, the power source of the drive circuit has a voltage necessary for driving the switching element and is configured to supply a sufficient current. For example, a floating power source circuit using a transformer is often applied. However, the drive circuit can be operated by a bootstrap power supply using a bootstrap circuit without using such a floating power supply circuit.

  By the way, when an overcurrent due to a ground fault occurs in the inverter circuit, the current when a ground fault occurs in the upper arm is likely to be larger than the current when a ground fault occurs in the lower arm. . Therefore, when a current detection circuit is added to detect an overcurrent due to a ground fault or the like, it is preferable to arrange the current detection circuit at a location where the current of the upper arm can be reliably detected. Preferably, a current detection circuit is arranged between the high-voltage DC positive line and the upper arm, but in this arrangement, the power source for operating the current detection circuit requires a higher voltage than the high-voltage DC positive line. It becomes. As one means, it is possible to construct a power supply circuit for a current detection circuit by configuring a floating power supply using a transformer or the like. However, the floating power supply has relatively large components such as a transformer, which increases the circuit scale of the rotating electrical machine drive device. In particular, when the floating power supply circuit using a transformer is not applied as the power supply of the drive circuit, and the downsizing of the rotating electrical machine drive device is attempted, the circuit scale of the power supply circuit for the current detection circuit is increased. It is not preferable. According to this characteristic configuration, when the current detection circuit is provided between the high-voltage DC positive line and the upper arm, a small-scale power supply circuit is constructed compared to a power supply circuit using a transformer. That is, according to this characteristic configuration, the current detection circuit operates by the detection circuit power supply generated by the detection circuit power supply circuit having the bootstrap circuit using the bootstrap power supply that supplies power to the drive circuit. Therefore, the function of detecting an overcurrent due to a ground fault or the like can be realized with a smaller circuit.

  As described above, when a current detection circuit is added in order to detect an overcurrent due to a ground fault or the like, it is preferable to arrange the current detection circuit at a location where the current of the upper arm can be reliably detected. When the current detection circuit is configured using, for example, a shunt resistor, it is preferable that the shunt resistor is disposed on the uppermost side of the complementary arm, that is, between the upper arm and the high-voltage positive power supply line. . In this case, the end of the shunt resistor on the upper arm side is the negative electrode side of the current detection circuit. Therefore, it is preferable that the detection circuit power supply circuit is configured with the end side of the upper arm side of the shunt resistor as the negative electrode. As one aspect, in the rotating electrical machine drive device according to the present invention, the current detection circuit includes a shunt resistor connected in series between a positive end of the complementary arm and the high-voltage DC positive line, and the shunt. An operational amplifier that detects a voltage across the resistor, and the detection circuit power supply circuit is forward-connected from the positive side of the bootstrap power supply toward the positive power supply terminal of the operational amplifier; and It is preferable to include a capacitor connected in series between the cathode terminal and the negative power supply terminal of the operational amplifier, and a resistor connected in parallel to the capacitor.

  Incidentally, some inverter circuits have switching elements and drive circuits integrated in one module. In such a module type inverter circuit, the complementary arms may be connected in parallel inside the module. In such a case, the terminals of the modules connected to the high-voltage positive power supply line and the high-voltage negative power supply line may be collectively provided for each complementary arm of each phase. . In such a module, since a current detection circuit cannot be individually installed for each complementary arm, there is no current detection circuit between the external terminal for the high voltage positive power supply line of the module and the high voltage positive power supply line. It is preferable to be installed. On the other hand, a power source for operating a drive circuit that relays a control signal to each switching element needs to be provided individually to each drive circuit, particularly with respect to the upper drive circuit. Therefore, a power supply for each upper drive circuit, for example, an external terminal that can be connected to a bootstrap power supply is also provided individually in such a module. The detection circuit power supply circuit is preferably configured so that any one of the bootstrap power supplies of the upper drive circuits can be used.

  As one aspect, in the rotating electrical machine drive device according to the present invention, the shunt resistor is connected in series between a positive side end of a parallel circuit in which the complementary arms of each phase are connected in parallel and the high-voltage DC positive line. The detection circuit power supply circuit is connected to the cathode terminals of a plurality of diodes connected in the forward direction from the positive side of the bootstrap power supply of each upper drive circuit toward the positive power supply terminal of the operational amplifier. A diode pair in which a cathode terminal pair is formed, a capacitor connected in series between the cathode terminal pair and the negative power supply terminal of the operational amplifier, and a resistor connected in parallel to the capacitor. It is preferable that Needless to say, the current detection circuits may be collectively installed after the complementary arms are connected in parallel, instead of the module type inverter circuit as described above.

Circuit block diagram schematically showing the system configuration of the rotating electrical machine drive device Circuit block diagram schematically showing configuration of additional circuit for current detection Circuit block diagram showing an example of an inverter circuit provided with an additional circuit for current detection Circuit block diagram showing a configuration example of a current detection additional circuit having a transformer

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings, taking as an example a rotating electrical machine driving device that controls a rotating electrical machine MG serving as a driving force source for a hybrid vehicle, an electric vehicle, or the like. The block diagram of FIG. 1 schematically shows the configuration of the rotating electrical machine driving device 100. The rotating electrical machine MG as a driving force source of the vehicle is a rotating electrical machine that operates by a plurality of phases of alternating current (here, three-phase alternating current), and can function as both an electric motor and a generator.

  In a vehicle such as an automobile that cannot receive power supply from an overhead line such as a railway, a secondary battery (battery) such as a nickel metal hydride battery or a lithium ion battery or an electric battery is used as a power source for driving a rotating electric machine. A DC power supply such as a multilayer capacitor is installed. In the present embodiment, for example, a high-voltage battery 11 (high-voltage DC power supply) having a power supply voltage of 200 to 400 [V] is provided as a high-voltage and large-capacity DC power supply for supplying power to the rotating electrical machine MG. Since the rotating electrical machine MG is an AC rotating electrical machine, an inverter circuit 10 that performs power conversion between direct current and alternating current is provided between the high voltage battery 11 and the rotating electrical machine MG. The DC voltage between the positive power supply line P (high voltage direct current positive line) and the negative power supply line N (high voltage direct current negative line) on the DC side of the inverter circuit 10 will be referred to as “system voltage Vdc” as appropriate in the following description. The high voltage battery 11 can supply electric power to the rotating electrical machine MG via the inverter circuit 10 and can store the electric power obtained by the electric power generation by the rotating electrical machine MG.

  Between the inverter circuit 10 and the high voltage battery 11, a smoothing capacitor 40 for smoothing a DC voltage (system voltage Vdc) is provided. Smoothing capacitor 40 stabilizes the DC voltage that fluctuates according to fluctuations in power consumption of rotating electrical machine MG. Between the smoothing capacitor 40 and the high voltage battery 11, a contactor 9 capable of disconnecting the electrical connection between the circuit from the smoothing capacitor 40 to the rotating electrical machine MG and the high voltage battery 11 is provided. In this embodiment, the contactor 9 is a mechanical relay that opens and closes based on a command from an unillustrated vehicle ECU (electronic control unit), which is one of the highest-level control devices of the vehicle. For example, a system main relay ( It is called SMR: system main relay. In addition, when the contactor 9 is opened, a discharge resistor is provided in parallel to the smoothing capacitor 40 in order to discharge the remaining charge of the smoothing capacitor 40.

  The inverter circuit 10 converts DC power having the system voltage Vdc into AC power of a plurality of phases (n is a natural number, n-phase, here 3 phases) and supplies the AC power to the rotating electrical machine MG, and AC power generated by the rotating electrical machine MG. The power is converted to DC power and supplied to the DC power supply. The inverter circuit 10 includes a plurality of switching elements. A power semiconductor element such as an IGBT (insulated gate bipolar transistor) or a power MOSFET (metal oxide semiconductor field effect transistor) is preferably applied to the switching element. As shown in FIG. 1, in this embodiment, IGBT3 is used as a switching element.

  As is well known, the inverter circuit 10 that converts power between direct current and multiple-phase alternating current (here, three-phase alternating current) has a number of arms corresponding to each of the multiple phases (here, three-phase). Consists of a bridge circuit. That is, as shown in FIG. 1, there are two between the DC positive side (positive power supply line P on the positive side of the DC power supply) and the DC negative side (negative power supply line N on the negative side of the DC power supply) of the inverter circuit 10. IGBT3 is connected in series and one arm 10L is comprised. Here, the IGBT 3 connected to the positive power supply line P is referred to as an upper stage IGBT 3U (upper stage switching element or high side switch), and the IGBT 3 connected to the negative power supply line N is referred to as a lower stage IGBT 3L (negative electrode side switching element or low side switch). ).

  When the upper stage IGBT 3U and the lower stage IGBT 3L are simultaneously turned on (conductive state), the positive power supply line P and the negative power supply line N are short-circuited, so that the upper stage IGBT 3U and the lower stage IGBT 3L are complementarily turned on. It is controlled to become. The arm 10L is configured as a complementary arm in which an upper arm provided with an upper IGBT 3U and a lower arm provided with a lower IGBT 3L are connected in series.

  In the case of three-phase alternating current, this series circuit (one arm 10L) is connected in parallel with three lines (three phases: 10U, 10V, 10W). That is, a bridge circuit in which a set of series circuits (arms 10L) corresponds to the stator coils corresponding to the U phase, V phase, and W phase of the rotating electrical machine MG is configured. The collector terminal of the upper stage IGBT 3U of each phase is connected to the positive power supply line P, and the emitter terminal is connected to the collector terminal of the lower stage IGBT 3L of each phase. In addition, the emitter terminal of the lower stage IGBT 3L of each phase is connected to the negative power supply line N (for example, the ground of the high-voltage circuit). An intermediate point of the series circuit (arm 10L) by the IGBTs 3 of each phase as a pair, that is, a connection point between the upper stage IGBT 3U and the lower stage IGBT 3L is connected to the stator coil of the rotating electrical machine MG. A free wheel diode 39 (regenerative diode) is connected to the IGBT 3 in parallel. The freewheel diode 39 is connected in parallel to each IGBT 3 such that the cathode terminal is connected to the collector terminal of the IGBT 3 and the anode terminal is connected to the emitter terminal of the IGBT 3.

  As shown in FIG. 1, the inverter circuit 10 is controlled by the control device 8. The control device 8 includes an ECU (electronic control unit) constructed using a logic circuit such as a microcomputer as a core member. In the present embodiment, the ECU uses a vector control method based on the target torque TM of the rotating electrical machine MG provided to the control device 8 as a request signal from another control device such as a vehicle ECU (not shown). Feedback control is performed to control the rotating electrical machine MG via the inverter circuit 10. The ECU of the control device 8 is configured to have various functional units for current feedback control, and each functional unit is realized by the cooperation of hardware such as a microcomputer and software (program). The

  The actual current flowing through the stator coil of each phase of the rotating electrical machine MG is detected by the current sensor 12, and the control device 8 acquires the detection result. In addition, the magnetic pole position at each time point of the rotor of the rotating electrical machine MG is detected by the rotation sensor 13, and the control device 8 acquires the detection result. The rotation sensor 13 is configured by, for example, a resolver. Here, the magnetic pole position represents the rotation angle of the rotor on the electrical angle. The ECU of the control device 8 feedback-controls the rotating electrical machine MG using the detection results of the current sensor 12 and the rotation sensor 13.

  In addition to the high voltage battery 11, the vehicle is also equipped with a low voltage battery 18 (low voltage DC power source) that is a power source having a lower voltage than the high voltage battery 11. The power supply voltage (+ B) of the low voltage battery 18 is, for example, 12 to 24 [V]. The control device 8 includes a regulator circuit and the like, and generates a power source suitable for operating a microcomputer and the like by electric power supplied from the low voltage battery 18. The low voltage battery 18 supplies electric power to an audio system, a lighting device, room lighting, illumination of instruments, a power window, and the like, and a control device that controls them, in addition to the control device 8 (ECU). The low voltage battery 18 and the high voltage battery 11 are insulated from each other and are in a floating relationship with each other.

  A gate terminal which is a control terminal of each IGBT 3 constituting the inverter circuit 10 is connected to the control device 8 (ECU) via the drive circuit 7 and is individually controlled to be switched. The operating voltage (power supply voltage of the circuit) is greatly different between a high voltage system circuit for driving the rotating electrical machine MG and a low voltage system circuit such as an ECU having a microcomputer as a core. For this reason, the control signal of the IGBT 3 generated by the control device 8 (ECU) of the low voltage system circuit is supplied to each IGBT 3 as a gate drive signal of the high voltage circuit system via the drive circuit 7. The drive circuit 7 is often configured to include an insulating element such as a photocoupler or a transformer.

  The control device 8 uses a voltage (for example, 5 [V] or 3.3 [V] generated from a voltage (+ B: for example, 12 [V]) of the low-voltage battery 18 using a control system power supply circuit (not shown) such as a regulator IC. ]) As a power supply voltage. A circuit on the control device 8 side of the drive circuit 7 including an insulating element such as a photocoupler or a transformer also operates with this power supply voltage. On the other hand, the circuit on the IGBT 3 side of the drive circuit 7 has a voltage “DV” higher than the voltage of the control system power supply circuit, and operates with power supplied from a power supply insulated from the control system power supply circuit. This voltage “DV” is generated by using a transformer from the voltage (+ B: 12 [V], for example) of the low voltage battery 18, or using a power supply circuit such as a transformer, a switching circuit, or a regulator circuit from the voltage of the high voltage battery 11. Generated. The voltage of “DV” with respect to the negative power supply line N is, for example, 15 to 20 [V].

  The power supply of each drive circuit 7 corresponding to each IGBT 3 is basically independent of each other. However, since the negative power supply line N is common to the lower IGBT 3L, a common ground (negative power supply line N) is provided. It becomes the power supply which has. Accordingly, the lower driver 7L, which is the drive circuit 7 corresponding to the lower IGBT 3L, operates with a common power source. As shown in FIG. 2, the power supply voltage “DV” is input to the “VCC” terminal of the lower driver 7L. The control signal input to the “IN” terminal of the lower driver 7L is output from the “OUT” terminal of the lower driver 7L as a gate drive signal having a potential difference between “DV” and the negative power supply line N, and the lower IGBT 3L Control switching.

  On the other hand, the upper driver 7U, which is a drive circuit corresponding to the upper stage IGBT 3U, has different power sources because the emitter terminal side of the upper stage IGBT 3U has a negative electrode (ground). In the present embodiment, the upper driver 7U has a negative-side potential (potential on the emitter terminal side of the upper-side IGBT 3U) of the upper-side arm as a negative electrode, and is raised by the bootstrap circuit with respect to the negative electrode. It operates by a bootstrap power supply 70 having a positive potential as a positive potential. The “predetermined voltage” substantially corresponds to the potential difference between the negative power supply line N and “DV”, as will be described later.

  The negative electrode of the upper arm (the emitter terminal of the upper IGBT 3U) is connected to the “VS” terminal of the upper driver 7U. The “VS” terminal is connected to the “VB” terminal via a capacitor 7 </ b> C constituting the bootstrap power supply 70. The “VB” terminal is further connected to a voltage “DV” via a resistor 7 </ b> R and a diode 7 </ b> D constituting the bootstrap power supply 70. The diode 7D is connected in series with the resistor 7R with the direction from the voltage “DV” to the “VB” terminal as the forward direction. A voltage lower than the “DV” by a forward voltage (0.6 to 0.7 [V]) of the diode 7D is applied to the “VB” terminal. As a result, the potential of the “VB” terminal becomes a potential that is substantially raised by the voltage “DV” with respect to the “VS” terminal. Therefore, the potential difference between the “VB” terminal and the “VS” terminal is substantially equal to the potential difference between the voltage “DV” and the negative power supply line N. The control signal input to the “IN” terminal of the upper driver 7U is output from the “OUT” terminal of the upper driver 7U as a gate drive signal having a potential difference between the “VB” terminal and the “VS” terminal, and the upper IGBT 3U Switching control.

  The inverter circuit 10 is provided with a current detection circuit 6 for detecting a current flowing through the arm 10L in the case of a ground fault in which the inverter circuit 10 contacts a case or the like and short-circuits. The detection result of the current detection circuit 6 is transmitted to the control device 8. For example, the control device 8 controls all the IGBTs 3 of the inverter circuit 10 to the OFF state and transmits the contactor 9 to the open state by transmitting it to the host control device (vehicle ECU).

  The current detection circuit 6 is installed on the upper arm side, and includes a shunt resistor 61 and an operational amplifier 62 that detects a voltage across the shunt resistor 61 (voltage between terminals). In order to detect the voltage across the shunt resistor 61 connected to the positive power supply line P, the power supply voltage for operating the operational amplifier 62 needs to be higher than the voltage across the shunt resistor 61. Therefore, power is supplied to the current detection circuit 6 from the detection circuit power supply circuit 63 that generates the detection circuit power supply using the bootstrap power supply 70 of the upper driver 7U.

  As shown in FIG. 2, the detection circuit power supply circuit 63 is configured by a parallel circuit of a resistor 6R and a capacitor 6C and a series circuit of a diode 6D. The diode 6 </ b> D is connected in the forward direction from the positive side of the bootstrap power supply 70 toward the positive power supply terminal of the operational amplifier 62. Specifically, the anode terminal of the diode 6 </ b> D is connected to the positive electrode of the bootstrap power supply 70, and the cathode terminal is connected to the positive electrode power supply terminal of the operational amplifier 62. A voltage lower than the positive electrode of the bootstrap power supply 70 by a forward voltage (0.6 to 0.7 [V]) of the diode 6D is applied to the positive power supply terminal (almost voltage “DV” is applied). )

  The cathode terminal of the diode 6D is further connected to the negative power supply terminal of the operational amplifier 62 via the resistor 6R and to the negative power supply terminal via the capacitor 6C. As a result, a potential difference of approximately “DV” is generated between the negative power supply terminal and the positive power supply terminal. The negative power supply terminal of the operational amplifier 62 is connected to one end side (IGBT 3 side) of the shunt resistor 61. The shunt resistor 61 has a resistance value such that the voltage between the terminals is preferably less than about “DV / 2” so that the voltage between the terminals is less than the voltage “DV” even when a large current flows through the shunt resistor 61 due to a ground fault or the like. Is set to For this reason, the potential on the other end side (positive power supply line P side) of the shunt resistor 61 becomes less than “DV” with respect to the potential of the negative power supply terminal of the operational amplifier 62, and the voltage across the shunt resistor 61 is reduced by the operational amplifier 62. Is detected well.

  Note that the power source for operating the operational amplifier 62 may be a floating power source 69 using a transformer as shown in FIG. 4 without using the bootstrap technique as illustrated in FIG. However, as can be easily understood by comparing FIG. 2 and FIG. 4, the circuit scale of the floating power supply 69 is much larger than the power circuit 63 for the detection circuit illustrated in FIG. 2. Therefore, operating the current detection circuit 6 with the detection circuit power supply generated by the detection circuit power supply circuit 63 as in the present embodiment suppresses an increase in the overall circuit scale of the rotating electrical machine drive device 100. It is suitable.

  As shown in FIG. 2, the current detection circuit 6 can be provided in each arm 10L. However, when it is not necessary to specify the phase in which the overcurrent is generated due to the ground fault or the like, the current detection circuit 6 is not individually provided for each arm 10L, and the overcurrent can also be detected collectively. It is. As in the present embodiment, in the case of having the three-phase arm 10L, three current detection circuits 6 are required to individually detect the current in each phase. In this case, one current detection circuit 6 is sufficient, and an increase in the overall circuit scale of the rotating electrical machine drive device 100 can be suppressed.

  FIG. 3 shows the configuration of such an inverter circuit 10. As an example, the inverter circuit 10 shown in FIG. 3 has an IPM (intelligent power module) 20 in which an IGBT 3 and a drive circuit 7 are integrated in one module as a core. In such an IPM 20, there are cases where terminals connected to the positive power supply line P and the negative power supply line N are collectively provided without being independent for each phase. Therefore, in such an IPM 20, the shunt resistor 61 cannot be individually connected to each arm 10L. However, as shown in FIG. 3, between the positive power supply line terminal of the IPM 20 and the positive power supply line P, It is possible to install a shunt resistor 61 in

  On the other hand, in this example, the IPM 20 also includes the drive circuit 7, but it is necessary to individually connect a bootstrap potential “DV” to the “VB” terminal of the upper driver 7U. For this reason, the “VB” terminals of the upper driver 7U are all provided as terminals of the IPM 20 so that they can be connected to the outside of the IPM 20. The anode terminals of the three diodes 6D constituting the detection circuit power supply circuit 63 are connected to the terminals of the IPM 20 connected to the “VB” terminal of each upper driver 7U. A cathode terminal pair in which the cathode terminals of the three diodes 6D are connected to each other is connected to the positive power supply terminal of the operational amplifier 62 of the current detection circuit 6. That is, the detection circuit power supply circuit 63 is connected in the form of wired OR so that any one of the bootstrap power supplies 70 of the upper driver 7U can be used. Here, the diodes 6D whose cathode terminals are connected to each other form a diode pair. The cathode terminal pair is connected to one end of each of the resistor 6R and the capacitor 6C. The other end sides of the resistor 6R and the capacitor 6C are connected to the negative power supply terminal of the operational amplifier 62 as described above.

  As described above, according to the present invention, the IGBT 3 and the drive circuit 7 are integrated into one module, and even for the IPM 20 having a configuration in which a circuit cannot be individually added to each arm 10L, small-scale current detection is performed. The overcurrent at the time of the ground fault can be detected simply by adding the additional circuit 60. In particular, the detection circuit power supply circuit 63 included in the current detection additional circuit 60 is a small circuit using small parts such as a diode 6D, a resistor 6R, and a capacitor 6C without using large parts such as a transformer. Thus, the current detection additional circuit 60 is greatly reduced in size.

  The present invention can be used in a rotating electrical machine driving apparatus that controls driving of an AC rotating electrical machine.

3: IGBT (switching element)
3L: Lower stage IGBT (switching element)
3U: Upper stage IGBT (switching element)
6: Current detection circuit 6C: Capacitor 6D: Diode 6R: Resistor 7: Drive circuit 7U: Upper driver (upper drive circuit)
8: Control device (inverter control unit)
9: Contactor 10: Inverter circuit 10L: Arm (complementary arm)
11: High voltage battery (high voltage DC power supply)
18: Low voltage battery (low voltage DC power supply)
61: Shunt resistor 62: Operational amplifier 63: Detection circuit power supply circuit 70: Bootstrap power supply 100: Rotating electric machine drive unit MG: Rotating electric machine N: Negative electrode power supply line (high-voltage DC negative electrode line)
P: Positive power supply line (high-voltage DC positive line)

Claims (3)

A rotating electrical machine drive device for driving and controlling an AC rotating electrical machine,
An upper arm provided between a high-voltage DC power supply and the rotating electrical machine, which performs power conversion between DC and a plurality of phases of AC, and includes a switching element and is connected to the high-voltage DC positive line side And an inverter constituted by a bridge circuit in which a complementary arm in which a switching element is provided and a lower arm connected to the high-voltage DC negative line side is connected in series is connected in parallel for the number of phases of a plurality of phases Circuit,
An inverter control unit that operates by power supplied from a low-voltage DC power supply having a voltage lower than that of the high-voltage DC power supply, generates a control signal for the switching element, and controls the inverter circuit;
A drive circuit for driving the switching element in response to the control signal,
Furthermore, a current detection circuit for detecting a current flowing through the at least one upper arm is provided between the upper arm and the high-voltage DC positive line,
Of the drive circuits, the upper drive circuit that drives the switching element of the upper arm has a negative potential on the negative side of the upper arm and is increased by a predetermined voltage with respect to the negative electrode. Operated by a bootstrap power supply with a positive potential,
The rotating electrical machine driving apparatus, wherein the current detection circuit is operated by a detection circuit power supply generated by a detection circuit power supply circuit having a bootstrap circuit using the bootstrap power supply. The current detection circuit includes a shunt resistor connected in series between a positive electrode side end of the complementary arm and the high-voltage DC positive electrode line, and an operational amplifier that detects a voltage across the shunt resistor,
The detection circuit power supply circuit includes a diode connected in a forward direction from a positive side of the bootstrap power supply to a positive power supply terminal of the operational amplifier, and between a cathode terminal of the diode and a negative power supply terminal of the operational amplifier. The rotating electrical machine drive device according to claim 1, comprising: a capacitor connected in series to the capacitor; and a resistor connected in parallel to the capacitor. The shunt resistor is connected in series between a positive side end of a parallel circuit in which the complementary arms of each phase are connected in parallel and the high-voltage DC positive line,
In the detection circuit power supply circuit, cathode terminals of a plurality of diodes connected in a forward direction from the positive side of the bootstrap power supply of each upper stage drive circuit toward the positive power supply terminal of the operational amplifier are connected to each other to form a cathode terminal A diode pair in which a pair is formed, a capacitor connected in series between the cathode terminal pair and the negative power supply terminal of the operational amplifier, and a resistor connected in parallel to the capacitor The rotating electrical machine drive device according to claim 2.

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