JP6984300B2 - Three-phase inverter device - Google Patents

Description

The present invention relates to a three-phase inverter device that drives a motor.

The three-phase inverter device that drives the motor is provided with a current detection unit for detecting the three-phase current in order to control the drive of the motor based on the three-phase current supplied to the motor. The current detector not only directly detects the phase current with a current sensor, but also detects the element current, which is the current flowing through each arm composed of switching elements such as IGBTs and power MOSFETs, and detects the element current. There is also a configuration in which the phase current is estimated from the detected value.

As a conventional technique for detecting such a failure of the current detection unit, for example, the techniques described in Patent Documents 1 and 2 can be mentioned. In the following, the configuration described in Patent Document 1 will be referred to as a first conventional configuration, and the configuration described in Patent Document 2 will be referred to as a second conventional configuration.

In the first conventional configuration, the position command value that commands the rotation position of the rotor of the motor, the estimated position that is the rotation position of the rotor estimated based on the current detection result by the current detection unit, and the position sensor detect it. When the three pieces of information, which is the rotation position of the rotor and the detection position, do not match or are out of the limited range, it is determined to be a failure.

In the second conventional configuration, a failure of the current detection unit is detected by combining a determination using the ripple of the input current to the inverter device and a determination using the sum of the three-phase currents output from the inverter device. At the same time, the failed current detector is identified.

Japanese Patent No. 5383925 Japanese Unexamined Patent Publication No. 2005-151754

In the first conventional configuration, it is possible to distinguish between the abnormality of the position command value, the failure of the position sensor, and the failure of the current detection unit from the combination of the three pieces of information. However, in the first conventional configuration, it is not possible to specify which of the current detection units is out of order, so the motor drive control is stopped after the current detection unit is detected to be out of order. I have no choice but to do it.

In the second conventional configuration, one of the current detectors is made by performing a determination using the ripple of the input current while changing and controlling the combination of the two-phase current detectors used for the drive control of the motor. It is designed to identify whether it is out of order. Therefore, in the second conventional configuration, the failed current detection unit cannot be identified until the maximum second control result is obtained, and the control using the current detection value by the failed current detection unit is continued until then. As a result, there is a possibility that the torque of the motor will continue to be excessive or insufficient.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a three-phase inverter device capable of identifying a failed current detection unit and shortening the period required for the identification. There is something in it.

The three-phase inverter device (1, 31, 41) according to claim 1 drives a motor (2), and has a position detection unit (10) and a three-phase half-bridge circuit (3u, 3v, 3w). ), A current detection unit (4 to 9, 20), a position estimation unit (23), and a failure detection processing unit (24, 44)). The position detection unit detects the rotational position of the rotor of the motor. The three-phase half-bridge circuit produces a three-phase current to supply to the motor. The current detection unit detects the element current flowing through the switching elements (13 to 18) constituting the half-bridge circuit or the output current of the half-bridge circuit. The position estimation unit estimates the rotation position of the rotor based on the current detection result by the current detection unit. The failure detection processing unit is based on the result of comparing the detection position, which is the rotation position of the rotor detected by the position detection unit, with the estimated position, which is the rotation position of the rotor estimated by the position estimation unit. Executes the failure detection process to detect. In this case, assuming that the three-phase half-bridge circuit is the first-phase half-bridge circuit (3u), the second-phase half-bridge circuit (3v), and the third-phase half-bridge circuit (3w), the position estimation unit , Current detection results for two phases corresponding to the first and second phases, current detection results for the two phases corresponding to the second and third phases, and corresponding to the third and first phases. The rotation position is estimated using each of the two-phase current detection results. Further, in this case, in the failure detection process, the detected position is compared with the estimated position estimated using the detection results of the currents of the two phases corresponding to the first phase and the second phase, and the estimated position is normal. The first determination process for determining whether or not the value is a normal value is compared with the detected position and the estimated position estimated using the detection results of the currents for the two phases corresponding to the second and third phases. Estimated position estimated using the second determination process to determine whether the estimated position is a normal value and the detection result of the detected position and the currents for the two phases corresponding to the third phase and the first phase. The current detection unit is based on the judgment results of the third judgment process, the first judgment process, the second judgment process, and the third judgment process, which determine whether or not the estimated position is a normal value. It includes a failure determination process for detecting a failure.

According to the above configuration, the failed current detection unit can be identified by executing the failure detection process for detecting the failure of the current detection unit based on the result of comparing the detection position and the estimated position. That is, when the detected position and the estimated position do not match, it can be determined that one of the current detection units corresponding to the current detection result used for estimating the estimated position is out of order. .. Then, by executing such a comparison between the detected position and the estimated position while changing the detection result of the current used for estimating the estimated position, the failed current detection unit can be identified.

Further, such a failure detection process is mainly performed by performing an operation, and the required time is extremely shorter than the motor control period required in the second conventional configuration. Therefore, according to the above configuration, it is possible to identify the failed current detection unit, and at the same time, it is possible to obtain an excellent effect that the period required for the identification can be shortened.

The figure which shows typically the structure of the three-phase inverter apparatus which concerns on 1st Embodiment. The figure which shows typically the content of the process which concerns on the failure detection of the current detection part which concerns on 1st Embodiment. The figure which shows typically the content of the motor current estimation processing which concerns on 1st Embodiment The figure which shows typically the content of the failure detection process which concerns on 1st Embodiment It is a figure for demonstrating the problem to be solved by 1st Embodiment, and is the timing chart which shows typically the motor current, the detection result of the current detection part, the ripple judgment result of an input current, and the torque output which concerns on the conventional configuration. A timing chart schematically showing the motor current, the detection result of the current detection unit, the position estimation result, and the torque output according to the first embodiment. The figure which shows typically the content of the failure detection process which concerns on 2nd Embodiment The figure which shows typically the structure of the three-phase inverter apparatus which concerns on 3rd Embodiment The figure which shows typically the content of the failure detection process which concerns on 3rd Embodiment It is a figure for demonstrating the problem to be solved by 4th Embodiment, and shows an example of a motor control waveform, a drive waveform, an estimated three-phase current waveform, and information about whether or not the current of each phase can be detected, and the identification of a failure. Timing chart The figure which shows typically the structure of the three-phase inverter apparatus which concerns on 4th Embodiment The figure which shows typically the content of the process which concerns on the failure detection of the current detection part which concerns on 4th Embodiment. The figure which shows typically the content of the 2nd failure detection processing which concerns on 4th Embodiment A timing chart showing an example of information on the motor control waveform, the drive waveform, the estimated three-phase current waveform, and the current detection availability and failure identification of each phase according to the fourth embodiment.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In each embodiment, substantially the same configuration is designated by the same reference numeral, and the description thereof will be omitted.
(First Embodiment)
Hereinafter, the first embodiment will be described with reference to FIGS. 1 to 6.

The three-phase inverter device 1 shown in FIG. 1 drives a motor 2, and includes an inverter main circuit 3, detection circuits 4 to 9, a position sensor 10, a controller 11, and the like. The motor 2 is, for example, a three-phase AC motor mounted on a vehicle. The inverter main circuit 3 converts, for example, a DC voltage supplied from a DC power supply 12 which is an in-vehicle battery through a pair of DC power supply lines L1 and L2 into three-phase AC voltages of U-phase, V-phase, and W-phase. Output.

The U-phase, V-phase, and W-phase, that is, the three-phase output terminals of the inverter main circuit 3 are connected to the three-phase terminals of the motor 2, respectively. As a result, the three-phase current, that is, the three-phase motor currents Iu, Iv, and Iw are supplied from the inverter main circuit 3 to the motor 2, and the motor 2 is driven. The inverter main circuit 3 includes three-phase half-bridge circuits 3u, 3v, and 3w connected between the DC power lines L1 and L2, respectively. The half-bridge circuits 3u, 3v, 3w generate three-phase motor currents Iu, Iv, Iw to supply to the motor 2. In the following, the motor current is also referred to as a phase current.

In this embodiment, the U phase corresponds to the first phase, the V phase corresponds to the second phase, and the W phase corresponds to the third phase. Therefore, in the present embodiment, the half-bridge circuit 3u corresponds to the first-phase half-bridge circuit, the half-bridge circuit 3v corresponds to the second-phase half-bridge circuit, and the half-bridge circuit 3w corresponds to the third-phase half-bridge. Corresponds to a circuit.

The half-bridge circuit 3u includes switching elements 13 and 14. The switching element 13 constituting the upper arm of the half-bridge circuit 3u is connected between the power supply line L1 on the high potential side and the node Nu which is the output terminal of the U phase of the inverter main circuit 3. The switching element 14 constituting the lower arm of the half-bridge circuit 3u is connected between the node Nu and the power line L2 on the low potential side.

The half-bridge circuit 3v includes switching elements 15 and 16. The switching element 15 constituting the upper arm of the half-bridge circuit 3v is connected between the power supply line L1 and the node Nv which is the output terminal of the V phase of the inverter main circuit 3. The switching element 16 constituting the lower arm of the half-bridge circuit 3v is connected between the node Nv and the power supply line L2.

The half-bridge circuit 3w includes switching elements 17 and 18. The switching element 17 constituting the upper arm of the half-bridge circuit 3w is connected between the power supply line L1 and the node Nw which is the output terminal of the W phase of the inverter main circuit 3. The switching element 18 constituting the lower arm of the half-bridge circuit 3w is connected between the node Nw and the power supply line L2.

The switching elements 13 to 18 are all N-channel type power MOSFETs including the main cell 19 and the sense cell 20. The main cell 19 is interposed in a main energization path for energizing the motor 2 from the inverter main circuit 3. That is, the drain of the main cell 19 of the switching elements 13, 15, and 17 constituting the upper arm is connected to the power supply line L1, and the source thereof is connected to the nodes Nu, Nv, and Nw, respectively. The drains of the main cells 19 of the switching elements 14, 16 and 18 constituting the lower arm are connected to the nodes Nu, Nv and Nw, respectively, and their sources are connected to the power supply line L2.

The sense cell 20 is for detecting an arm current, that is, an element current flowing in the main cell 19, and a current corresponding to the current flowing in the main cell 19 flows at a predetermined diversion ratio. The diversion ratio is determined by the size ratio of the main cell 19 and the sense cell 20 and the like. According to such a configuration, even when a relatively large current flows through the main cell 19, the current can be easily detected.

The gates of the main cell 19 and the sense cell 20 are commonly connected, and a drive signal output from the controller 11 is given to the common gate. Specifically, drive signals G_up and G_un are given to the gates of the U-phase switching elements 13 and 14, respectively, and drive signals G_vp and G_vn are given to the V-phase switching elements 15 and 16 respectively, and the W-phase switching elements 15 and 16 are given drive signals G_vp and G_vn, respectively. Drive signals G_wp and G_wn are given to the switching elements 17 and 18, respectively.

Each source of the main cell 19 and the sense cell 20 is connected to the input terminals of the detection circuits 4 to 9, respectively. The detection circuits 4 to 9 detect the element current flowing through the switching elements 13 to 18 based on the current flowing through the sense cell 20. Therefore, in the present embodiment, the sense cell 20 and the detection circuits 4 to 9 constitute a current detection unit.

The detection circuits 4 to 9 detect the current flowing through the sense cells 20 of the switching elements 13 to 18, and output a current detection signal representing the detected value. Specifically, the U-phase detection circuits 4 and 5 output current detection signals I_up and I_un representing the detected values of the current flowing through the sense cells 20 of the switching elements 13 and 14, respectively.

The V-phase detection circuits 6 and 7 output current detection signals I_vp and I_vn representing the detected values of the current flowing through the sense cells 20 of the switching elements 15 and 16, respectively. The W-phase detection circuits 8 and 9 output current detection signals I_wp and I_wn representing the detected values of the current flowing through the sense cells 20 of the switching elements 17 and 18, respectively.

The current detection signals I_up to I_wn output from the detection circuits 4 to 9 are given to the controller 11. Although not shown, specific configurations of the detection circuits 4 to 9 include, for example, an OP amplifier to which the source voltages of the main cell 19 and the sense cell 20 are input, an OP amplifier output terminal, and an OP amplifier output terminal. It is possible to adopt a configuration including a resistor connected between the sources of the sense cell 20 and an A / D converter in which the voltage across the resistor is input.

According to the above configuration, the voltage across the resistor becomes a voltage corresponding to the current flowing through the sense cell 20, and a digital signal obtained by A / D converting such a voltage is transmitted to the controller 11 as a current detection signal. Further, in the above configuration, the source of the main cell 19 and the source of the sense cell 20 have the same potential due to the operation of the OP operational amplifier. Therefore, the controller 11 can accurately detect the element current flowing in the main cell 19 based on the current detection signal corresponding to the current flowing in the sense cell 20.

The position sensor 10 detects the rotational position of the rotor of the motor 2, and corresponds to the position detection unit. The position sensor 10 outputs a position detection signal Sp corresponding to the detected rotation position to the controller 11. The controller 11 controls the drive of the motor 2, and includes a motor current estimation unit 21, a drive control unit 22, a position estimation unit 23, a failure detection processing unit 24, and the like.

The motor current estimation unit 21 detects the element current flowing through the switching elements 13 to 18 based on the current detection signals I_up to I_wn given from the detection circuits 4 to 9, and the phase currents Iu and Iv from the detected element currents. , The process of estimating Iw and the execution of. The process for detecting the element current described above is performed at a normal detection timing corresponding to the control method of the motor 2. For example, when the control method of the motor 2 is a control method for comparing triangular waves, the timing at which the triangular wave signal as a carrier reaches the maximum value or the minimum value, that is, the apex corresponds to a normal detection timing.

The motor current estimation unit 21 may not be able to detect the element currents of the three phases at such a normal detection timing. The reason is as follows. That is, since the detection circuits 4 to 9 of the present embodiment have the above-described configuration, the element current cannot be correctly detected unless the switching elements 13 to 18 are driven on.

Depending on the control state of the motor 2, the normal detection timing and the period during which the drive signal given to the switching elements 13 to 18 is on-level for a short period, that is, the period during which the on-pulse width is short may overlap. The motor current estimation unit 21 cannot detect the element currents for three phases. In this case, the motor current estimation unit 21 estimates the element current of the remaining one phase that could not be detected from the element currents of the two phases that could be detected.

The motor current estimation unit 21 outputs a possibility signal indicating whether or not the failure detection process described later can be executed to the failure detection processing unit 24. Although the details will be described later, when the motor current estimation unit 21 can detect the element currents of the three phases based on the current detection signals I_up to I_wn, the phase currents Iu and Iv are used from the element currents of the three phases. , Iw is obtained, and a pass / fail signal indicating that the execution of the failure detection process is “possible” is output.

Further, when the motor current estimation unit 21 can detect only the element currents of two phases based on the current detection signals I_up to I_wn, the motor current estimation unit 21 obtains the corresponding two-phase phase currents from the element currents of those two phases, and also obtains the corresponding two-phase phase currents. The phase current of the remaining one phase is estimated from the element currents of those two phases. The method for estimating the phase current will be described later. When only the element currents for two phases can be detected, the motor current estimation unit 21 estimates the phase currents Iu, Iv, and Iw as described above, and indicates that the execution of the failure detection process is "No". Outputs a pass / fail signal to represent.

The drive control unit 22 controls the operation of the half-bridge circuits 3u, 3v, and 3w based on the current detection result by the current detection unit and the rotation position detection result by the position sensor 10. Specifically, the drive control unit 22 drives the inverter main circuit 3 based on the phase currents Iu, Iv, Iw estimated by the motor current estimation unit 21 and the position detection signal Sp given from the position sensor 10. Drive signals G_up to G_wn are generated and output. With such a configuration, the current flowing through the motor 2 and the rotation position of the motor 2 are feedback-controlled so as to match the target values.

In controlling the drive of the motor 2 as described above, the drive control unit 22 generates each phase switching command value (voltage instantaneous value) for instructing the switching state of each phase of the inverter main circuit 3. ing. The drive control unit 22 outputs the generated phase switching command value to the position estimation unit 23.

The position estimation unit 23 estimates the rotational position of the rotor of the motor 2 based on the current detection result by the current detection unit. Specifically, the position estimation unit 23 estimates the rotation position based on the phase currents Iu, Iv, Iw estimated by the motor current estimation unit 21 and the phase switching command values given by the drive control unit 22. As a specific method for such estimation, for example, the method disclosed in JP-A-2015-223023 can be adopted.

In this case, the position estimation unit 23 estimates the rotation position of the rotor based on the detection result of the currents for the two phases corresponding to the U phase and the V phase. Further, the position estimation unit 23 estimates the rotation position of the rotor based on the detection result of the currents for the two phases corresponding to the V phase and the W phase. Further, the position estimation unit 23 estimates the rotation position of the rotor based on the detection result of the currents for the two phases corresponding to the W phase and the U phase.

The failure detection processing unit 24 can execute a failure detection process for detecting a failure of the current detection unit. Although the details will be described later, the failure detection process is based on the result of comparing the detection position which is the rotation position of the rotor detected by the position sensor 10 with the estimated position which is the rotation position of the rotor estimated by the position estimation unit 23. This is a process for detecting a failure of the current detection unit. The detection position is acquired based on the position detection signal Sp. The failure detection processing unit 24 executes the failure detection process when the pass / fail signal given from the motor current estimation unit 21 is "possible", but executes the failure detection process when the pass / fail signal is "no". do not do.

As described above, in the present embodiment, the current detection unit is composed of the sense cell 20 and the detection circuits 4 to 9. Therefore, in this case, the failure of the current detection unit includes not only the circuit failure of the detection circuits 4 to 9, but also the element failure of the switching elements 13 to 18 including the sense cell 20 and the wiring failure such as the disconnection of the wiring related to the sense cell 20. Is also included.

The failure detection process of the present embodiment includes a first determination process, a second determination process, a third determination process, and a failure determination process. In the first determination process, the detection position is compared with the estimated position estimated using the detection results of the currents for the two phases corresponding to the U phase and the V phase (hereinafter referred to as the first estimated position), and the first determination process is performed. 1 This is a process of determining whether or not the estimated position is a normal value.

In the second determination process, the detection position is compared with the estimated position estimated using the detection results of the currents for the two phases corresponding to the V phase and the W phase (hereinafter referred to as the second estimated position), and the second determination process is performed. 2 This is a process of determining whether or not the estimated position is a normal value. In the third determination process, the detection position is compared with the estimated position estimated using the detection results of the currents for the two phases corresponding to the W phase and the U phase (hereinafter referred to as the third estimated position), and the third determination process is performed. 3 This is a process of determining whether or not the estimated position is a normal value. The failure determination process is a process of detecting a failure of the current detection unit based on the determination results of the first determination process, the second determination process, and the third determination process.

Next, the operation of the above configuration will be described.
[1] Overall flow of processing related to failure detection of the current detection unit Among the processes by the controller 11, the processing related to failure detection of the current detection unit is the processing as shown in FIG. First, in step S100, the element current flowing through the switching elements 13 to 18 is detected based on the current detection signals I_up to I_wn, and the rotational position of the rotor of the motor 2 is detected based on the position detection signal Sp.

The current detection and the rotation position detection in step S100 are performed at the same timing. This is because, in the first to third determination processes, the detected position and the estimated position are compared, and it is determined whether or not the estimated position is a normal value based on the comparison result. Here, if the current detection and the rotation position detection are performed at different timings, the detection position and the estimated position may differ significantly even if an abnormality such as a failure does not occur in the current detection unit. , There is a possibility that an error may occur in the above determination.

In order to prevent such an erroneous determination, it is necessary to perform the above comparison using the detected position and the estimated position at the same timing. Therefore, in the present embodiment, the current detection and the rotation position detection are performed at the same timing. The "same timing" here means that the detection timings are completely the same and there is no deviation, but also a slight deviation that can prevent the above-mentioned erroneous judgment is allowed. can do.

Further, the detection timing in this case is a normal detection timing corresponding to the control method of the motor 2. For example, in the case of the triangle wave comparison control method, the timing at which the triangular wave signal as a carrier reaches the apex, that is, the maximum value or the minimum value corresponds to the normal detection timing.

In step S200, the motor current estimation process for estimating the phase currents Iu, Iv, and Iw from the element current detected in step S100 is executed. The details of the motor current estimation process will be described later. In step S300, the element currents for three phases can be detected based on the pass / fail signal, and it is determined whether or not the three-phase current is estimated from the detected values of the element currents. If the element currents for the three phases cannot be detected, the result is "NO" in step S300, and the process ends. On the other hand, if the element currents for the three phases can be detected, the result is "YES" in step S300, and the process proceeds to step S400. In step S400, a failure detection process for detecting a failure of the current detection unit is executed. The details of the failure detection process will be described later.

[2] Contents of motor current estimation processing The motor current estimation processing of the present embodiment has the contents as shown in FIG. First, in step S201, it is determined whether or not the element current for three phases can be detected at the normal detection timing. If the element currents for three phases can be detected at the normal detection timing, the result is “YES” in step S201, and the process proceeds to step S202.

In step S202, the values of the phase currents Iu, Iv, and Iw are obtained from the detected values of the element currents. Specifically, the value of the phase current Iu is updated to the detected value of the element current of the U phase, the value of the phase current Iv is updated to the detected value of the element current of the V phase, and the value of the phase current Iw is the W phase. It is updated to the detected value of the element current.

The detected value of the element current of each phase described above is the detected value of the element current of the upper arm or the lower arm of each phase, and in FIG. 3 and the following description, the detected value I_u *, the detected value I_v *, and the detection. It is expressed as a value I_w *. After the execution of step S202, the process proceeds to step S203. In this case, the element current for three phases can be detected. Therefore, in step S203, the pass / fail signal is set to "possible".

If the element current for three phases cannot be detected at the normal detection timing, the result is "NO" in step S201, and the process proceeds to step S204. In step S204, it is determined whether or not the U-phase element current could be detected. If the U-phase element current cannot be detected, the result is "YES" in step S204, and the process proceeds to step S205.

In step S205, the values of the respective phase currents Iu, Iv, and Iw are obtained from the detected values I_v * and I_w *. Specifically, in step S205, the value of the phase current Iv is updated to the detected value I_v *, and the value of the phase current Iw is updated to the detected value I_w *. Further, the value of the phase current Iu is obtained by calculation using the detected values I_v * and I_w *.

That is, in the configuration of the present embodiment, if each circuit is normal, the sum of the phase currents Iu, Iv, and Iw becomes zero, that is, "Iu + Iv + Iv = 0" is established. Therefore, in step S205, the value of the phase current Iu is calculated based on the following equation (1) by utilizing the fact that the sum of the phase currents Iu, Iv, and Iw becomes zero.
Iu = -I_v * -I_w * ... (1)

On the other hand, if the element current of the U phase can be detected, the result becomes "NO" in step S204, and the process proceeds to step S206. In step S206, it is determined whether or not the V-phase element current could be detected. If the element current of the V phase cannot be detected, the result is "YES" in step S206, and the process proceeds to step S207.

In step S207, the values of the phase currents Iu, Iv, and Iw are obtained from the detected values I_u * and I_w *. Specifically, in step S207, the value of the phase current Iu is updated to the detected value I_u *, and the value of the phase current Iw is updated to the detected value I_w *. Further, the value of the phase current Iv is obtained by calculation using the detected values I_u * and I_w *. In this case, the value of the phase current Iv is calculated based on the following equation (2) by utilizing the fact that the sum of the phase currents Iu, Iv, and Iw becomes zero as in step S205.
Iv = -I_u * -I_w * ... (2)

On the other hand, if the element current of the V phase can be detected, the result becomes "NO" in step S206, and the process proceeds to step S208. In step S208, the values of the respective phase currents Iu, Iv, and Iw are obtained from the detected values I_u * and I_v *. Specifically, in step S208, the value of the phase current Iu is updated to the detected value I_u *, and the value of the phase current Iv is updated to the detected value I_v *. Further, the value of the phase current Iw is obtained by calculation using the detected values I_u * and I_v *. In this case, the value of the phase current Iw is calculated based on the following equation (3) by utilizing the fact that the sum of the phase currents Iu, Iv, and Iw becomes zero as in steps S205 and S207.
Iw = -I_u * -I_v * ... (3)

After the execution of steps S205, S207 or S208, the process proceeds to step S209. In this case, the element currents for the three phases cannot be detected. Therefore, in step S209, the pass / fail signal is set to "no". The reason for doing this is as follows. That is, when the element current for three phases cannot be detected, the phase current of the phase for which the element current cannot be detected is calculated based on the above equations (1) to (3).

Therefore, in this case, the sum of the three phases is always zero. In such a state where the sum of the three phases is always zero, accurate determination cannot be made in the failure detection process described later. For this reason, when the element currents for the three phases cannot be detected, the pass / fail signal is set to "No" so that the failure determination process is not executed. After the execution of step S203 or S209, the motor current estimation process ends.

As described above, in the motor current estimation process of the present embodiment, when the element currents for three phases cannot be detected, the phase in which the element currents could not be detected is U phase → V phase →. It is designed to be confirmed in the order of W phase. The order of processing for such confirmation is not necessarily limited to this order, and may be replaced. Further, such confirmation processing does not necessarily have to be sequential processing as shown in FIG. 3, and parallel processing may be performed.

[3] Contents of the failure detection process The failure detection process of the present embodiment has the contents as shown in FIG. First, in step S401, whether or not the first estimated position estimated using the detection results of the currents for the two phases corresponding to the U phase and the V phase is a normal value (hereinafter referred to as a normal value). Judged.

Specifically, in step S401, the detected position and the first estimated position are compared, and as a result of the comparison, if the difference between the two is less than a predetermined threshold value, it is determined that the first estimated position is a normal value. If the difference between the two is equal to or greater than the threshold value, it is determined that the first estimated position is not a normal value. It should be noted that the threshold value is such that the desired detection accuracy can be obtained for the failure detection of the current detection unit in consideration of the position estimation accuracy including the current detection accuracy in the above configuration, the position detection accuracy of the position sensor 10, and the like. You can set it to a value.

If the first estimated position is not a normal value, the result is "NO" in step S401, and the process proceeds to step S402. In step S402, it is determined whether or not the second estimated position estimated using the detection results of the currents for the two phases corresponding to the V phase and the W phase is a normal value. Specifically, in step S402, the detected position and the second estimated position are compared, and as a result of the comparison, if the difference between the two is less than the above threshold value, it is determined that the second estimated position is a normal value. If the difference between the two is equal to or greater than the above threshold value, it is determined that the second estimated position is not a normal value.

If the second estimated position is not a normal value, the result is "NO" in step S402, and the process proceeds to step S403. In step S403, it is determined whether or not the third estimated position estimated using the detection results of the currents for the two phases corresponding to the W phase and the U phase is a normal value. Specifically, in step S403, the detected position and the third estimated position are compared, and as a result of the comparison, if the difference between the two is less than the above threshold value, it is determined that the third estimated position is a normal value. If the difference between the two is equal to or greater than the above threshold value, it is determined that the third estimated position is not a normal value. If the first estimated position is a normal value, the result is "YES" in step S401, and the process proceeds to step S404. Step S404 is a process having the same contents as step S402.

Here, when the first estimated position is a normal value and the second estimated position is not a normal value, the result is “YES” in step S401 and “NO” in step S404, and the process proceeds to step S405. In this case, since the second estimated position is not a normal value, it is considered that at least one of the V-phase and W-phase current detection units has failed. Further, in this case, since the first estimated position is a normal value, it is considered that the U-phase and V-phase current detection units are normal.

Therefore, in this case, it can be identified that the W-phase current detection unit is out of order. Therefore, in step S405, it is determined that a failure has occurred in the W-phase current detection unit, and it is prohibited to use the current detection result by the W-phase current detection unit in various controls executed thereafter.

If the first estimated position is not a normal value and the second estimated position is a normal value, the result is "NO" in step S401 and "YES" in step S402, and the process proceeds to step S406. In this case, since the first estimated position is not a normal value, it is considered that at least one of the U-phase and V-phase current detection units has failed. Further, in this case, since the second estimated position is a normal value, it is considered that the V-phase and W-phase current detection units are normal.

Therefore, in this case, it can be identified that the U-phase current detection unit is out of order. Therefore, in step S406, it is determined that a failure has occurred in the U-phase current detection unit, and it is prohibited to use the current detection result by the U-phase current detection unit in various controls executed thereafter.

Further, when the first estimated position and the second estimated position are not normal values and the third estimated position is a normal value, the result is "NO" in steps S401 and S402 and "YES" in step S403, and step S407. Proceed to. In this case, since the first estimated position is not a normal value, it is considered that at least one of the U-phase and V-phase current detection units has failed. Further, in this case, since the second estimated position is not a normal value, it is considered that at least one of the V-phase and W-phase current detection units has failed. Further, in this case, since the third estimated position is a normal value, it is considered that the W phase and U phase current detection units are normal.

Therefore, in this case, it can be identified that the V-phase current detection unit is out of order. Therefore, in step S407, it is determined that a failure has occurred in the V-phase current detection unit, and it is prohibited to use the current detection result by the V-phase current detection unit in various controls executed thereafter.

If the first estimated position, the second estimated position, and the third estimated position are not normal values, the result is "NO" in steps S401, S402, and S403, and the process proceeds to step S408. In this case, since all of the first estimated position, the second estimated position, and the third transition position are not normal values, the current detection unit corresponding to at least two phases, that is, two or more current detection units are out of order. Conceivable. Therefore, in step S408, it is determined that two or more current detection units have failed.

If the first estimated position and the second estimated position are normal values, "YES" is set in steps S401 and S402, and the process proceeds to step S409. In this case, since it is considered that all of the three-phase current detection units are normal, it is possible to continue the control of the motor 2. Therefore, in step S409, it is determined that the control can be continued, and the process ends.

Further, even after the execution of steps S405, S406 or S407, the process proceeds to step S409. In this case as well, since it is considered that the two-phase current detection unit is normal, it is possible to continue the control of the motor 2. Therefore, in step S409, it is determined that the control can be continued, and the process ends.

On the other hand, after the execution of step S408, the process proceeds to step S410. In this case, it is considered that at least two or more current detection units among the three-phase current detection units are out of order, so that it is impossible to continue the control of the motor 2. Therefore, in step S410, it is determined that control cannot be continued, and the process ends.

In each process shown in FIG. 4, step S401 corresponds to the first determination process, steps S402 and S404 correspond to the second determination process, and step S403 corresponds to the third determination process. Further, steps S405, S406, S407 and S408 correspond to the failure determination process.

As described above, in the failure detection process of the present embodiment, the failed current detection unit is compared between the detected position and the estimated position while changing the current detection result used for estimating the estimated position. Is designed to be specified. That is, in the failure detection process of the present embodiment, the failed current detection unit is specified by executing the first determination process, the second determination process, and the third determination process in combination in a predetermined order. .. It should be noted that such an order is not necessarily limited to the order shown in FIG. 4, and may be replaced. Further, these processes do not necessarily have to be sequential processes as shown in FIG. 4, and may be parallel processes.

According to the present embodiment described above, the following effects can be obtained.
The controller 11 of the three-phase inverter device 1 of the present embodiment compares the detection position, which is the rotation position of the rotor detected by the position sensor 11, with the estimated position, which is the rotation position of the rotor estimated by the position estimation unit 23. A failure detection processing unit 24 that executes a failure detection process for detecting a failure of the current detection unit based on the result is provided. According to such a configuration, the failed current detection unit can be identified by executing the failure detection process for detecting the failure of the current detection unit based on the result of comparing the detection position and the estimated position. That is, when the detected position and the estimated position do not match, it can be determined that one of the current detection units corresponding to the current detection result used for estimating the estimated position is out of order. .. Then, by executing such a comparison between the detected position and the estimated position while changing the detection result of the current used for estimating the estimated position, the failed current detection unit can be identified.

Further, such a failure detection process is mainly performed by performing an operation, and the required time is extremely short compared to the motor control period required in the above-mentioned second conventional configuration. Become. Therefore, according to the present embodiment, it is possible to identify the failed current detection unit, and at the same time, it is possible to obtain an excellent effect that the period required for the identification can be shortened.

Hereinafter, such differences between the present embodiment and the second conventional configuration will be described with reference to FIGS. 5 and 6. In FIG. 5, the uppermost stage shows the actual three-phase motor current, the second stage from the top shows the detected three-phase motor current (current detection result), and the third stage from the top shows the input current. The result of the ripple judgment is shown, and the lowermost row shows the torque output. Further, in FIG. 6, the uppermost stage shows the actual three-phase motor current, and the second stage from the top shows the detected three-phase motor current (current detection result, which is estimated by the motor current estimation unit 21). The phase currents Iu, Iv, and Iw) are shown, the third row from the top shows the determination results of the first estimated position, the second estimated position, and the third estimated position, and the lowermost row shows the torque output.

As shown in FIG. 5, in the second conventional configuration, the failure determination is performed using the feedback result (ripple of the input current). Therefore, for example, when a failure occurs in the U-phase current detection unit, after the failure occurs. , The determination result does not immediately become "abnormal" (the failure flag is not set), and a predetermined delay time Ta exists between the occurrence of the failure and the setting of the failure flag.

Further, in the second conventional configuration, in order to prevent erroneous detection, time Tb, Tc, and Td for confirming the failure detection are required. As a result, in the second conventional configuration, it takes a relatively long period from the occurrence of a failure in the U-phase current detection unit to the identification of the failed current detection unit, and that period is the current of the failed U-phase. Control using the current detection value by the detection unit will be continued. Therefore, during the above period, the torque of the motor becomes unstable (excessive or insufficient torque) temporarily.

On the other hand, as shown in FIG. 6, in the present embodiment, the failure determination is not based on the feedback result. Therefore, for example, when a failure occurs in the U-phase current detection unit, the determination is made immediately after the failure occurs. The result is "abnormal" (fault flag is set), and there is almost no delay time from the occurrence of the failure to the setting of the failure flag.

Further, in the present embodiment, the time Te for confirming the failure detection is only the time required for the calculation for executing the process related to the failure detection, and the total time of the times Tb, Tc, and Td in the second conventional configuration is sufficient. It will be a very short time compared to. As a result, in the present embodiment, the period required from the occurrence of a failure in the U-phase current detection unit to the identification of the failed current detection unit is relatively short. Therefore, according to the present embodiment, the period in which the torque of the motor 2 becomes unstable can be suppressed to a shorter period than in the second conventional configuration.

In the failure detection process of the present embodiment, the first determination process for comparing the detected position with the first estimated position and determining whether or not the first estimated position is a normal value, and the detected position and the second estimation are performed. The second determination process of comparing with the position and determining whether or not the second estimated position is a normal value is compared with the detected position and the third estimated position, and the third estimated position is a normal value. It includes a third determination process for determining whether or not, and a failure determination process for detecting a failure of the current detection unit based on the determination results of the first determination process, the second determination process, and the third determination process. ..

According to such a failure detection process, when one of the three-phase current detection units fails, the failed current detection unit can be identified. Therefore, according to the present embodiment, even if one current detection unit fails, stable control can be continued by using the normal remaining two-phase current detection unit. Further, according to the above-mentioned failure detection process, when the motor control is continued after one current detection unit fails, if another current detection unit fails, the failure can be detected. .. Further, according to the failure detection process, it is possible to detect that two or more current detection units among the three-phase current detection units have failed during the control of the motor 2.

The switching elements 13 to 18 constituting the three-phase half-bridge circuits 3u, 3v, and 3w are configured to include a main cell 19 and a sense cell 20. The detection circuits 4 to 9 constituting the current detection unit of the present embodiment are configured to detect the element current flowing through the switching elements 13 to 18 based on the current flowing through the sense cell 20. According to such a configuration, the manufacturing cost of the apparatus can be kept low and the physique of the apparatus can be kept small as compared with the configuration provided with the current sensors for detecting the phase currents Iu, Iv, and Iw. Then, according to the failure detection process of the present embodiment, it is possible to detect a failure of the current detection unit having such an element current detection configuration, and it is possible to obtain the above-mentioned effect with respect to the failure detection.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to FIG. 7.
In the second embodiment, the content of the failure detection process is different from that in the first embodiment. The configuration of the three-phase inverter device 1 is the same as that of the first embodiment.

The position estimation unit 23 of the present embodiment is based on the estimation of the first estimated position, the second estimated position, and the third estimated position, as well as the detection results of the currents for the three phases corresponding to the U phase, the V phase, and the W phase. Estimate the rotation position of the rotor. Further, in the failure detection process of the present embodiment, the detection position is further compared with the estimated position estimated using the detection result of the current for three phases (hereinafter referred to as the fourth estimated position), and the first 4 A fourth determination process for determining whether or not the estimated position is a normal value is included.

In this case, in the failure detection process, as a result of executing the fourth determination process, if it is determined that the fourth estimated position is a normal value, it is determined that all the current detection units have not failed, and the second 4 When it is determined that the estimated position is not a normal value, the first determination process, the second determination process, and the third determination process are executed.

The failure detection process of this embodiment is as shown in FIG. 7. As shown in FIG. 7, in the failure detection process of the present embodiment, step S421 is provided in place of step S404 of the failure detection process of the first embodiment. Step S421 is a process corresponding to the fourth determination process, and is executed first when the failure detection process is started.

In step S421, it is determined whether or not the fourth estimated position estimated using the detection results of the currents for the three phases is a normal value. Specifically, in step S421, the detected position and the fourth estimated position are compared, and as a result of the comparison, if the difference between the two is less than the above threshold value, it is determined that the fourth estimated position is a normal value. If the difference between the two is equal to or greater than the above threshold value, it is determined that the fourth estimated position is not a normal value.

If the fourth estimated position is a normal value, the result is "YES" in step S421, and the process proceeds to step S409. In this case, since it is considered that all of the three-phase current detection units are normal, it is possible to continue the control of the motor 2. Therefore, in step S409, it is determined that the control can be continued, and the process ends.

On the other hand, if the fourth estimated position is not a normal value, the result becomes "NO" in step S421, and the process proceeds to step S401. In this case, it is considered that at least one of the three-phase current detectors has a failure. Therefore, by executing steps S401 to S403, an attempt is made to identify the failed current detection unit, and the process proceeds to any of steps S405 to S408 according to the result.

The process flow and contents of steps S401 to S410 in the present embodiment are the first except that the process proceeds to step S405 when the first estimated position is a normal value, that is, when "YES" in step S401. Since the process flow and contents of steps S401 to S410 in one embodiment are the same, the description thereof will be omitted.

As described above, in the failure detection process of the present embodiment, the fourth determination process is first executed, and in the fourth determination process, it is determined that the fourth estimated position is a normal value. In this case, it is determined that no failure has occurred in all the current detection units, and the control of the motor 2 is continued. By doing so, it is determined that the control of the motor 2 may be continued only by executing one process (step S421) in the failure detection process in the steady state where no failure has occurred in the current detection unit. Can be reached.

On the other hand, in the first embodiment, it cannot be determined that the control of the motor 2 may be continued unless two processes (steps S401 and S402) are executed in the failure detection process in the steady state. .. Therefore, according to the failure detection process of the present embodiment, there is an effect that the processing load on the controller 11 in the steady state can be reduced as compared with the failure detection process of the first embodiment.

(Third Embodiment)
Hereinafter, the third embodiment will be described with reference to FIGS. 8 and 9.
As shown in FIG. 8, the three-phase inverter device 31 of the present embodiment is different from the three-phase inverter device 1 of the first embodiment in that the controller 32 is provided in place of the controller 11. The controller 32 is different from the controller 11 in that a three-phase total calculation unit 33 is added.

The three-phase total calculation unit 33 calculates the absolute value of the phase currents Iu, Iv, Iw estimated by the motor current estimation unit 21, that is, the total sum of the three-phase currents, and outputs the calculation result to the failure detection processing unit 24. The sum calculation process can be executed. In this case, the three-phase total calculation unit 33 is given a pass / fail signal output from the motor current estimation unit 21. The three-phase sum calculation unit 33 executes the sum calculation process when the pass / fail signal is “possible”, but does not execute the sum calculation process when the pass / fail signal is “no”. The three-phase sum calculation unit 33 may be configured to always execute the sum calculation process regardless of the pass / fail signal.

The failure detection process of the present embodiment includes a total determination process in addition to each process included in the failure detection process of the second embodiment. The total determination process is a process executed when it is determined that the estimated position is not normal in all of the first determination process, the second determination process, the third determination process, and the fourth determination process, and is a three-phase current. This is a process for determining whether or not the total sum of is a normal value.

Then, in the failure detection process of the present embodiment, when the total sum of the three-phase currents is determined to be a normal value in the total sum determination process, it is determined that the position sensor 10 is out of order, and the three-phase current is determined in the total sum determination process. When it is determined that the total current is not a normal value, it is determined that the current detection unit for two phases is out of order.

The failure detection process of this embodiment is as shown in FIG. 9. As shown in FIG. 9, the failure detection process of the present embodiment is different from the failure detection process of the second embodiment in that steps S431 and S432 are added. Step S431 is a process corresponding to the total determination process, and is executed when all of steps S421 and S401 to S403 are "NO".

In step S421, it is determined whether or not the absolute value of the total sum of the three-phase currents (hereinafter, abbreviated as the sum of the three phases) is a normal value. Specifically, in step S421, when the sum of the three phases is less than the predetermined determination threshold value, it is determined that the sum of the three phases is a normal value, and when the sum of the three phases is equal to or more than the above determination threshold value. Is judged that the sum of the three phases is not a normal value.

As described above, in the present embodiment, the total sum of the three-phase currents is zero. Therefore, if the current detection unit is normal, the total sum of the three phases calculated by the three-phase total calculation unit is zero. Therefore, it is possible to determine whether or not the total of the three phases is a normal value depending on whether or not the total of the three phases is zero.

However, due to the influence of various errors in the current detection configuration, it is possible that the calculated sum of the three phases will not be completely zero even if the current detection unit is normal. Therefore, in the present embodiment, the determination threshold value is set to a value at which erroneous determination does not occur due to the influence of such an error, for example, a value larger than zero by a predetermined margin.

Here, if the sum of the three phases is equal to or greater than the determination threshold value, the result becomes “NO” in step S431, and the process proceeds to step S408. In this case, since all of the first to fourth estimated positions and the sum of the three phases are not normal values, it is considered that one or both of the current detector and the position sensor 10 corresponding to at least two phases are out of order. .. Therefore, the process proceeds to step S408, after which it is determined in step S410 that control cannot be continued, and the process ends.

On the other hand, if the sum of the three phases is less than the determination threshold value, the result is "YES" in step S431, and the process proceeds to step S432. In this case, it is determined that the first to fourth estimated positions are not normal values, and the sum of the three phases is determined to be normal values. Therefore, in this case, it is considered that although the current detection unit is normal, it is determined that the first to fourth estimated positions are not normal values because the position sensor 10 has a failure.

Therefore, in step S432, it is determined that the position sensor 10 has a failure. In this case, since it is considered that all of the three-phase current detection units are normal, the control of the motor 2 can be continued by switching the rotation position of the rotor used for the motor control from the detected value to the estimated value. The above switching can be realized by giving the drive control unit 22 the estimated position estimated by the position estimation unit 23 instead of the position detection signal Sp. Therefore, after the execution of step S432, the process proceeds to step S409, it is determined that control can be continued, and the process ends.

As described above, in the failure detection process of the present embodiment, when it is determined that all the first to fourth estimated positions are not normal values, it is determined whether or not the sum of the three phases is a normal value. The summation judgment process is executed. By doing so, when it is determined that all the first to fourth estimated positions are not normal values, it is determined whether two or more current detectors are out of order or the position sensor 10 is out of order. It becomes possible to discriminate. Then, when it is specified that the position sensor 10 is out of order, the control of the motor 2 can be continued by switching the rotation position of the rotor used for the motor control from the detected value to the estimated value.

(Fourth Embodiment)
Hereinafter, the fourth embodiment will be described with reference to FIGS. 10 to 14.
As described above, when the device current detection configuration is adopted as the current detection unit, the device current for three phases may not be detected at the normal detection timing. In particular, in the control method for triangle wave comparison, when the motor 2 is controlled at high output or high rotation, the carrier apex and the period when the on-pulse width of the drive signal is short may continuously overlap, and the element current for three phases may overlap. May continue for a period in which the failure determination process cannot be executed without being able to detect.

FIG. 10 shows an example of a state in which the element currents for three phases cannot be continuously detected. In FIG. 10, the uppermost stage shows a motor control waveform, specifically, a triangular wave signal, a U-phase modulated wave signal, a V-phase modulated wave signal, and a W-phase modulated wave signal, which are carriers, and the second stage from the top shows a drive. The waveform, specifically the U-phase drive signal, the V-phase drive signal, and the W-phase drive signal is shown, and the third stage from the top shows the waveform of the estimated three-phase current.

In the case of the example shown in FIG. 10, the element currents for three phases cannot be detected at all of the normal detection timings t1 to t13, and as a result, the failure determination process is executed for a relatively long period of time. Can not do it. If the period during which the failure determination process cannot be executed is prolonged, the detection may be delayed when a failure occurs in the current detection unit.

Even if the failure detection process in each of the above embodiments is executed in a state where only the element currents of two phases can be detected, the presence or absence of a failure of the current detection unit can be determined, but the failed current detection unit is specified. Can not do it. Hereinafter, the reason for this will be described with reference to FIG.

At the bottom of FIG. 10, it is estimated using information on whether or not the current of each phase can be detected and identification of a failure, specifically, the current detection result by the current detection unit corresponding to any of the upper and lower arms of each phase. Information on whether or not the position is judged to be a normal value, information indicating the result of the judgment (normal or abnormal) (hereinafter, also referred to as estimated position judgment information), presence or absence of failure of the current detection unit (possible) Information on whether or not the failed current detector could be identified is shown.

As shown in FIG. 10, in this case, at times t4, t6, and t11, although the first determination process using the detection results of the currents for the two phases corresponding to the U phase and the V phase can be executed, the first determination process can be executed. 2. The third determination process cannot be executed. Further, at times t2, t5, t7, t9, and t12, although the second determination process using the detection results of the currents for the two phases corresponding to the V phase and the W phase can be executed, the first and third determination processes can be executed. Judgment processing cannot be executed. Further, at times t1, t3, t8, and t10, although the third determination process using the current detection results for the two phases corresponding to the U phase and the W phase can be executed, the first and second determination processes can be executed. Cannot be executed.

Therefore, for example, when a failure occurs in the current detection unit corresponding to the V-phase upper arm at a predetermined timing between the times t2 and t3, the current detection unit is subjected to the first determination process executed at the time t4. Although it is possible to detect that a failure has occurred, it is not possible to identify the failed current detector. Therefore, in the present embodiment, a device for solving such a problem is added.

As shown in FIG. 11, the three-phase inverter device 41 of the present embodiment is different from the three-phase inverter device 1 of the first embodiment in that the controller 42 is provided in place of the controller 11. The controller 42 is different from the controller 11 in that a storage unit 43 is added and a failure detection processing unit 44 is provided in place of the failure detection processing unit 24.

The storage unit 43 stores information similar to the information related to current detection availability and failure identification of each phase shown in the lowermost part of FIG. That is, the storage unit 43 has information on whether or not the estimated position is a normal value using the current detection result of the current detection unit corresponding to which of the upper and lower arms of each phase, and the determination thereof. Information associated with the results, information indicating whether or not there is a possibility of failure of the current detection unit, and information indicating whether or not the failed current detection unit can be identified are stored.

The failure detection processing unit 44 has, in addition to the same failure detection processing as the failure detection processing unit 24 of the first to third embodiments (hereinafter referred to as the first failure detection process), a failure detection process having different contents (hereinafter referred to as the failure detection process). , Second failure detection process) can be executed. The failure detection processing unit 44 executes the first failure detection process when the pass / fail signal given from the motor current estimation unit 21 is "possible", and the second failure detection when the pass / fail signal is "no". Execute the process.

Next, the operation of the above configuration will be described.
[1] Overall flow of processing related to failure detection of the current detection unit As shown in FIG. 12, the processing related to failure detection of the current detection unit of the present embodiment is the failure of the current detection unit of the first embodiment. Step S500 is added to the process related to the detection.

In the present embodiment, when the element currents for three phases can be detected, the result is "YES" in step S300, the process proceeds to step S400, and the first failure detection process is executed. As the first failure detection process, any one of the failure detection processes shown in FIGS. 4, 7 and 9 can be adopted. On the other hand, if the element currents for the three phases cannot be detected, the result becomes "NO" in step S300, the process proceeds to step S500, and the second failure detection process is executed. The content of the second failure detection process will be described later.

[2] Contents of the second failure detection process The second failure detection process has the contents as shown in FIG. First, in step S501, the rotation position of the rotor is estimated using the current detection result by the current detection unit corresponding to the two arms detected this time. In the following, the current detection unit corresponding to the two arms detected this time is also simply referred to as "this arm". In step S502, it is determined whether or not there is a possibility that the current detection unit has a failure. This determination can be performed based on the information stored in the storage unit 43.

Here, if there is no possibility that the current detection unit has a failure, "YES" is set in step S502, and the process proceeds to step S503. In step S503, it is determined whether or not the estimated position estimated in step S501 is a normal value. This determination can be performed by the same method as the first to third determination processes (steps S401 to S403) described above. Here, if the estimated position is a normal value, the result is "YES" in step S503, and the process proceeds to step S504. In this case, since it cannot be determined that the current detection unit may have a failure, it is determined in step S504 that the control can be continued, and the process ends.

On the other hand, if the estimated position is not a normal value, the result becomes "NO" in step S503, and the process proceeds to step S505. In step S505, the determination is made using the arm this time, and the determination information of the estimated position that the determination result is "abnormal" and the information that the current detection unit may be out of order are obtained. It is stored in the storage unit 43.

If the storage unit 43 already stores information that the current detection unit may have a failure, the result is "NO" in step S502, and the process proceeds to step S506. In step S506, it is determined whether or not the arm in this time includes an arm in which "abnormality" is stored in the determination information of the estimated position. Here, if the arm in which the "abnormality" is stored is not included in the arm this time, the result becomes "NO" in step S506, and the process proceeds to step S507.

Step S507 is the same process as step S503, and it is determined whether or not the estimated position estimated in step S501 is a normal value. Here, if the estimated position is a normal value, the result is "YES" in step S507, and the process proceeds to step S504. In this case, since the estimated position estimated without using the current detection result by the current detection unit corresponding to the arm with the possibility of abnormality is a normal value, the two-phase current detection unit corresponding to the arm this time is used. It is considered that no failure has occurred. Therefore, in step S504, it is determined that the control can be continued, and the process ends.

On the other hand, if the estimated position is not a normal value, the result becomes "NO" in step S507, and the process proceeds to step S508. In this case, since the estimated position estimated without using the current detection result by the current detection unit corresponding to the arm that may be abnormal is not a normal value, the two-phase current detection unit corresponding to this arm It is considered that at least one of them has a failure. That is, in this case, it is considered that at least two or more current detection units among the three-phase current detection units are out of order, so that it is impossible to continue the control of the motor 2. Therefore, the process proceeds to step S509, it is determined that the control cannot be continued, and the process ends.

If the arm this time includes an arm in which "abnormality" is stored, the result is "YES" in step S506, and the process proceeds to step S510. In step S510, it is determined whether or not only one arm in which the "abnormality" is stored is included in the arm this time. Here, if both of the arms this time are arms in which "abnormality" is stored, the result becomes "NO" in step S510, and the process proceeds to step S504. In this case, the determination using the same combination of the two arms has already been performed, and the "abnormality" is stored as the result of the determination. Therefore, in this case, it is not possible to determine that two or more current detection units are out of order and to specify the out-of-order current detection unit. Therefore, in step S504, it is determined that the control can be continued, and the process ends.

On the other hand, when only one arm in which "abnormality" is stored is included in the arm this time, "YES" is obtained in step S510, and the process proceeds to step S511. Step S511 is the same process as step S503 and the like, and it is determined whether or not the estimated position estimated in step S501 is a normal value. Here, if the estimated position is not a normal value, the result becomes "NO" in step S511, and the process proceeds to step S504.

In this case, since the estimated position estimated using the current detection result including only one arm with the possibility of abnormality is not a normal value, the two-phase current detector corresponding to this arm It is considered that at least one or both of them have failed. However, in this case, it is not possible to determine that two or more current detection units are out of order and to specify the failure of the current detection unit. Therefore, in step S504, it is determined that the control can be continued, and the process ends.

On the other hand, when the estimated position is a normal value, "YES" is obtained in step S511, and the process proceeds to step S512. In this case, since the estimated position estimated using the current detection result including one of the two arms having a possibility of abnormality is a normal value, the two arms having a possibility of abnormality have. It is probable that the current detector corresponding to the other of them is out of order. Therefore, in step S512, it is identified that the current detection unit corresponding to the other of the two arms that may be abnormal is out of order, and the remaining arms are identified as normal. The information to be represented is stored in the storage unit 43.

In this case, since the two-phase current detection unit is considered to be normal, it is possible to continue the control of the motor 2. Therefore, after the execution of step S512, the process proceeds to step S504, it is determined that control can be continued, and the process ends. In each process shown in FIG. 13, steps S503, S507 and S511 compare the detected position with the estimated position estimated using the detection result of the current for two phases, and the estimated position is a normal value. Corresponds to the determination process for determining whether or not.

As described above, the failure detection processing unit 44 included in the controller 42 of the present embodiment is divided into two phases when the pass / fail signal is "No", that is, when only the detection result of the current for two phases can be obtained. The second failure detection process performed by using the current detection result of the above is executed. Further, the controller 42 of the present embodiment includes a storage unit 43 that stores various information (information regarding current detection availability of each phase and identification of failure) obtained by the second failure detection process. According to such a configuration, even if the device current for three phases cannot be detected at the normal detection timing due to continuous control with a short drive pulse width, the failure of the current detection unit is detected. , The failed current detector can be identified.

Hereinafter, the effects obtained by the present embodiment will be described with reference to a specific example shown in FIG. In FIG. 14, the uppermost stage shows the motor control waveform, the second stage shows the drive waveform, the third stage shows the waveform of the estimated three-phase current, and the lowermost stage shows information on whether or not the current of each phase can be detected and the failure identification. .. As shown in FIG. 14, for example, when a failure occurs in the current detection unit corresponding to the V-phase upper arm at a predetermined timing between time t2 and t3, the failure of the current detection unit is detected as follows. At the same time, the failed current detector is identified.

That is, at time t3, a determination (second failure detection process) is performed using the current detection result by the current detection unit corresponding to the U-phase lower arm and the W-phase lower arm. In this case, since the current detection units corresponding to the above arms are all normal, "normal" is stored as the determination information of the estimated position. The flow of the second failure detection process executed at time t3 is "YES" in S501 → S502 → “YES” → S504 in S503.

At time t4, a determination is made using the current detection result by the current detection unit corresponding to the U-phase upper arm and the V-phase upper arm. In this case, since the current detection unit corresponding to the V-phase upper arm is out of order, "abnormality" is stored as the determination state of the estimated position, and "yes" is possible that the current detection unit is out of order. Is remembered. However, at this point, since the failed current detection unit cannot be specified, the failure identification is "x". The flow of the second failure detection process executed at time t4 is “YES” in S501 → S502 → “NO” in S503 → S505 → S504.

At time t5, a determination is made using the current detection result by the current detection unit corresponding to the V-phase lower arm and the W-phase lower arm. In this case, since the current detection units corresponding to the above arms are all normal, "normal" is stored as the determination information of the estimated position. The flow of the second failure detection process executed at time t5 is “NO” in S501 → S502 → “NO” in S506 → “YES” → S504 in S507.

At time t6, a determination is made using the current detection result by the current detection unit corresponding to the U-phase upper arm and the V-phase upper arm. In this case, since the current detection unit corresponding to the V-phase upper arm is out of order, "abnormality" is stored as the determination state of the estimated position, and "yes" is possible that the current detection unit is out of order. Is remembered. However, at this point, since the failed current detection unit cannot be specified, the failure identification is "x". The flow of the second failure detection process executed at time t6 is “NO” in S501 → S502 → “YES” in S506 → “NO” → S504 in S510.

At time t7, a determination is made using the current detection result by the current detection unit corresponding to the V-phase lower arm and the W-phase lower arm. In this case, since the current detection units corresponding to the above arms are all normal, "normal" is stored as the determination information of the estimated position. The flow of the second failure detection process executed at time t7 is “NO” in S501 → S502 → “NO” in S506 → “YES” → S504 in S507.

At time t8, a determination is made using the current detection result by the current detection unit corresponding to the U-phase upper arm and the W-phase upper arm. In this case, since the current detection units corresponding to the above arms are all normal, "normal" is stored as the determination state of the estimated position. That is, at this point, the information that at least one of the current detection units corresponding to the U-phase upper arm and the V-phase upper arm is out of order, and the current detection unit corresponding to the U-phase upper arm and the W-phase upper arm are either. It means that the information that is normal is obtained.

By combining these information, it is possible to identify that the current detection unit corresponding to the V-phase upper arm is out of order. Therefore, at this point, it is specified that the failed current detection unit is "on the V phase". The flow of the second failure detection process executed at time t8 is "S501-> S502 for" NO "-> S506 for" YES "-> S510 for" YES "-> S511 for" YES "-> S512-> S504". ..

As described above, according to the present embodiment, as shown in FIG. 14, even if the element current for three phases cannot be detected for a relatively long period of time at the normal detection timing, the element current for two phases can be detected. By executing the second failure detection process performed based on the result, it is possible to detect the failure of the current detection unit and identify the failed current detection unit. Therefore, according to the present embodiment, for example, when the motor 2 is controlled at high output or high rotation in the control method for triangle wave comparison, the element current for three phases cannot be detected at the normal detection timing. Even in the case of continuous operation, when a failure occurs in the current detection unit, the failure can be quickly detected and the failed current detection unit can be identified.

(Other embodiments)
It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, and can be arbitrarily modified, combined, or extended without departing from the gist thereof.
The numerical values and the like shown in each of the above embodiments are examples and are not limited thereto.

The detection circuits 4 to 9 may be configured to detect the element current flowing through the switching elements 13 to 18, and the specific configuration thereof can be appropriately changed. For example, when the current flowing through the half-bridge circuits 3u, 3v, and 3w is relatively small, a configuration without a sense cell 20 is used as the switching elements 13 to 18, and the element current flowing through the main cell 19 is directly detected by a shunt resistor or the like. It may be configured. In this case, the current detection unit is configured by the detection circuits 4 to 9 and the shunt resistor.

The current detection unit is not limited to the configuration of detecting the element currents of the switching elements 13 to 18, and is configured by a Hall-type current sensor or the like that detects the three-phase current output from the half-bridge circuits 3u, 3v, and 3w. You may. When such a configuration is adopted, a configuration that does not include the sense cell 20 as the switching elements 13 to 18 can be used, and the detection circuits 4 to 9 can be omitted. Further, in this case, the value detected by the current sensor becomes the value of the phase currents Iu, Iv, and Iw as it is, and there is no period during which the current cannot be detected as in the configuration of the element current detection. Therefore, when the above configuration is adopted, the processing of steps S200 and S300 in the processing related to the failure detection of the current detection unit shown in FIG. 2 and the like becomes unnecessary.

The switching element constituting the half-bridge circuit is not limited to the switching elements 13 to 18 which are power MOSFETs, and various power elements such as IGBTs, that is, power devices can be used.

In the third embodiment, the absolute value of the total sum of the three-phase currents is obtained and the absolute value is compared with the determination threshold value, but it is not necessary to obtain the absolute value of the total sum of the three-phase currents. In this case, in step S421, the determination threshold is set to two thresholds, plus and minus, and it is determined whether or not the sum of the three-phase currents is included in the value within the range from the minus threshold to the plus threshold. Should be added.

The present disclosure has been described in accordance with the examples, but it is understood that the present disclosure is not limited to the examples and structures. The present disclosure also includes various variations and variations within a uniform range. In addition, various combinations and forms, as well as other combinations and forms that include only one element, more, or less, are within the scope and scope of the present disclosure.

1, 31, 41 ... Three-phase inverter device, 2 ... Motor, 3u, 3v, 3w ... Half bridge circuit, 4-9 ... Detection circuit, 10 ... Position sensor, 13-18 ... Switching element, 19 ... Main cell, 20 ... Sense cell, 23 ... Position estimation unit, 24, 44 ... Failure detection processing unit, 33 ... Three-phase total calculation unit.

Claims (5)

A three-phase inverter device (1, 31, 41) that drives a motor (2).
A position detection unit (10) that detects the rotation position of the rotor of the motor, and
A three-phase half-bridge circuit (3u, 3v, 3w) that generates a three-phase current to supply to the motor, and
A current detection unit (4 to 9, 20) for detecting the element current flowing through the switching elements (13 to 18) constituting the half-bridge circuit or the output current of the half-bridge circuit, and
A position estimation unit (23) that estimates the rotation position of the rotor based on the current detection result of the current detection unit, and a position estimation unit (23).
A failure of the current detection unit is caused based on the result of comparing the detection position which is the rotation position of the rotor detected by the position detection unit and the estimated position which is the rotation position of the rotor estimated by the position estimation unit. The failure detection processing unit (24, 44) that executes the failure detection process to be detected, and
Equipped with
When the three-phase half-bridge circuit is a first-phase half-bridge circuit (3u), a second-phase half-bridge circuit (3v), and a third-phase half-bridge circuit (3w), it is assumed.
The position estimation unit detects the currents of the two phases corresponding to the first phase and the second phase, and the currents of the two phases corresponding to the second phase and the third phase. And the detection result of the current for two phases corresponding to the third phase and the first phase, and the rotation position is estimated by using each of them.
For the failure detection process,
The detected position is compared with the estimated position estimated using the detection results of the currents for the two phases corresponding to the first phase and the second phase, and whether or not the estimated position is a normal value. The first judgment process to determine whether or not
The detected position is compared with the estimated position estimated using the detection results of the currents for the two phases corresponding to the second phase and the third phase, and whether or not the estimated position is a normal value. The second judgment process to determine whether or not
The detected position is compared with the estimated position estimated using the detection results of the currents for the two phases corresponding to the third phase and the first phase, and whether or not the estimated position is a normal value. The third judgment process to determine whether or not
A failure determination process for detecting a failure of the current detection unit based on the determination results of the first determination process, the second determination process, and the third determination process.
Includes a three-phase inverter device. The switching element includes a main cell (19) and a sense cell (20).
The three-phase inverter device according to claim 1, wherein the current detection unit detects the element current based on the current flowing through the sense cell. The position estimation unit further estimates the rotation position using the detection results of the currents for three phases.
For the failure detection process,
Further, a fourth determination process of comparing the detected position with the estimated position estimated using the detection result of the current for the three phases and determining whether or not the estimated position is a normal value is performed. Included,
When it is determined in the fourth determination process that the estimated position is a normal value, it is determined that the current detection unit has not failed, and it is determined that the current detection unit has not failed.
The fourth determination process according to claim 1 or 2 , wherein when the estimated position is determined not to be a normal value, the first determination process, the second determination process, and the third determination process are executed. Three-phase inverter device. Further, a three-phase total calculation unit (33) for calculating the total of the three-phase currents supplied to the motor based on the detection result of the currents for the three phases by the current detection unit is provided.
For the failure detection process,
Further, the process is executed when it is determined that the estimated position is not normal in all of the first determination process, the second determination process, the third determination process, and the fourth determination process. It includes a total sum determination process that determines whether the total sum of the three-phase currents is a normal value.
When it is determined in the total sum determination process that the total sum of the three-phase currents is a normal value, it is determined that the position detection unit is out of order.
The three-phase inverter according to claim 3 , wherein when it is determined in the total sum determination process that the total sum of the three-phase currents is not a normal value, it is determined that the current detection unit for the two phases is out of order. Device. A three-phase inverter device (1, 31, 41) that drives a motor (2).
A position detection unit (10) that detects the rotation position of the rotor of the motor, and
A three-phase half-bridge circuit (3u, 3v, 3w) that generates a three-phase current to supply to the motor, and
A current detection unit (4 to 9, 20) for detecting the element current flowing through the switching elements (13 to 18) constituting the half-bridge circuit or the output current of the half-bridge circuit, and
A position estimation unit (23) that estimates the rotation position of the rotor based on the current detection result of the current detection unit, and a position estimation unit (23).
A failure of the current detection unit is caused based on the result of comparing the detection position which is the rotation position of the rotor detected by the position detection unit and the estimated position which is the rotation position of the rotor estimated by the position estimation unit. The failure detection processing unit (24, 44) that executes the failure detection process to be detected, and
Equipped with
The switching element includes a main cell (19) and a sense cell (20).
The current detection unit is configured to detect the element current based on the current flowing through the sense cell.
Further, it is provided with a storage unit (43) for storing various information.
When the detection result of the current for three phases is obtained, the failure detection processing unit (44) executes the first failure detection process having the same contents as the failure detection process, and the current for two phases. If only the detection result of is obtained, the second failure detection process having different contents from the failure detection process is executed.
In the second failure detection process, the detected position is compared with the estimated position estimated using the detection result of the current for the two phases, and it is determined whether or not the estimated position is a normal value. Judgment processing is included
A three-phase inverter device that stores the determination result of the determination process in the storage unit.

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