JP2004328854A - Discharge controller, discharge control method, and its program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely discharge a capacitor. <P>SOLUTION: This discharge controller has an electric machine, an inverter 40, a capacitor 17 which is arranged between the DC power source and the inverter 40, a voltage command value generating and processing means 91 which generates a voltage command value for driving the electric machine, a pulse width converting means which generates a pulse width modulation signal, based on the voltage command value, and supplies it to the inverter 40. Then, the pulse width converting means makes specified harmonic waves into a pulse width modulation signal when the supply of the current from the above DC power source to the inverter 40 is interrupted. Since the specified harmonic waves are made into a pulse width modulation signal when the supply of a current from the DC power source to the inverter 40 is interrupted, it can supply the electric machine with AC currents. The charge accumulated in the capacitor 17 can be consumed within the electric machine. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a discharge control device, a discharge control method, and a program thereof.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a vehicle drive device mounted on an electric vehicle as an electric vehicle and generating a drive motor torque, that is, a drive motor torque, and transmitting the drive motor torque to drive wheels, the drive motor includes a power running ( At the time of driving), the battery is driven by receiving a DC current from the battery to generate the drive motor torque, and at the time of regeneration (power generation), the torque is received by the inertia of the electric vehicle to generate a DC current, and the current is supplied to the battery. Supply.
[0003]
Further, in a vehicle drive device that is mounted on a hybrid vehicle as an electric vehicle and transmits a part of the engine torque, that is, part of the engine torque to a generator (generator motor) and the rest to drive wheels, A planetary gear unit including a sun gear, a ring gear, and a carrier; connecting the carrier to an engine; connecting a ring gear and a drive motor to a drive wheel; connecting a sun gear and a generator; The output rotation is transmitted to driving wheels to generate driving force.
[0004]
In each of the vehicle drive devices, an inverter is provided between the drive motor and the drive motor control device, and the inverter is operated in accordance with a drive signal sent from the drive motor control device. , The U-phase, V-phase, and W-phase currents are generated, and the currents of the respective phases are supplied to the drive motor to drive the drive motor. In the hybrid vehicle, an inverter is also provided between the generator and the generator control device. The inverter is operated according to a drive signal sent from the generator control device to drive the generator. Generate a DC current, send the DC current to the battery, charge the battery, receive a DC current from the battery to generate a current for each phase, and supply the current for each phase to the generator , To drive the generator.
[0005]
To this end, the inverter comprises a plurality of, for example, six transistors. Therefore, when a drive signal is sent to each transistor in a predetermined pattern, the transistors are turned on and off, and each phase current or a DC current is generated.
[0006]
By the way, when the running of the electric vehicle is completed and the ignition switch is turned off, in conjunction therewith, for example, the supply of current from the battery to the inverter is cut off, and the driving of the drive motor is stopped. At this time, a charge corresponding to the capacitance is stored in a capacitor provided between the battery and the inverter. Then, when the power of the drive motor control device is turned off while the electric charge is stored in the capacitor, the drive signal sent to each transistor is transiently put into an uncontrolled state. As a result, the transistor is turned on, a short-circuit current flows, and the durability of the drive motor control device may be reduced.
[0007]
Therefore, a discharge control device is provided, and the capacitor is discharged by the discharge control device. For this purpose, the discharge control device provides a current command value for excitation, for example, a d-axis current command value id. ^* To a non-zero value (a predetermined value other than zero (0)), a torque current command value, for example, a q-axis current command value iq. ^* Is substantially zero, thereby driving the drive motor without generating the drive motor torque and consuming the electric charge accumulated in the capacitor in the drive motor (for example, see Patent Document 1). .
[0008]
Further, when the other discharge control device drives the drive motor, the d-axis current command value id ^* And q-axis current command value iq ^* Performs position asynchronous current control by adding harmonics to the drive motor, cancels the drive motor torque in the drive motor, consumes the charge stored in the capacitor in the drive motor, and does not transmit the drive motor torque to the drive shaft (For example, see Patent Document 2).
[0009]
[Patent Document 1]
JP-A-9-70196
[0010]
[Patent Document 2]
JP-A-9-215102
[0011]
[Problems to be solved by the invention]
However, in each of the conventional discharge control devices, it is necessary to drive a drive motor. In this case, it is necessary to detect a phase current by a current sensor and a magnetic pole position by a resolver. If an abnormality occurs in the resolver or the like, the capacitor cannot be discharged.
[0012]
An object of the present invention is to solve the problems of the conventional discharge control device and to provide a discharge control device, a discharge control method, and a program capable of reliably discharging a capacitor.
[0013]
[Means for Solving the Problems]
Therefore, in the discharge control device of the present invention, the electric machine including the rotor and the stator, an inverter that is supplied with a DC current from a DC power supply, generates an AC current, and supplies the generated AC current to the electric machine; A capacitor disposed between the power supply and the inverter, a voltage command value generation processing means for generating a voltage command value for driving the electric machine, and generating a pulse width modulation signal based on the voltage command value; Pulse width conversion processing means for supplying the pulse width conversion processing to the inverter.
[0014]
When the supply of current from the DC power supply to the inverter is interrupted, the pulse width conversion processing means uses a predetermined harmonic as a pulse width modulation signal.
[0015]
Another discharge control device according to the present invention further includes current feedback control processing means for generating a shaft voltage command value based on a current deviation between a current supplied to the electric machine and a current command value.
[0016]
In still another discharge control device of the present invention, further, a shaft voltage command value generation processing means for generating a predetermined harmonic as a shaft voltage command value when supply of current from the DC power supply to the inverter is interrupted. Having.
[0017]
Still another discharge control device of the present invention further includes a conversion processing means for converting a shaft voltage command value to a phase voltage command value.
[0018]
In still another discharge control device of the present invention, further, a phase voltage for generating a predetermined harmonic as a phase voltage command value of each phase of the coil when the supply of current from the DC power supply to the inverter is interrupted. Command value generation processing means is provided.
[0019]
In the discharge control method of the present invention, a DC current is received from a DC power supply, an AC current is generated and supplied to the electric machine, a voltage command value for driving the electric machine is generated, and the voltage command value is generated. , A pulse width modulation signal is generated and supplied to the inverter, and when the supply of current from the DC power supply to the inverter is interrupted, a predetermined harmonic is used as the pulse width modulation signal.
[0020]
In the program of the discharge control method according to the present invention, the computer includes a voltage command value generation processing unit that generates a voltage command value for driving the electric machine, and a pulse width modulation signal that is generated based on the voltage command value. Function as pulse width conversion processing means for supplying the pulse width conversion processing.
[0021]
When the supply of current from the DC power supply to the inverter is interrupted, the pulse width conversion processing means uses a predetermined harmonic as a pulse width modulation signal.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this case, an electric vehicle as an electric vehicle will be described.
[0023]
FIG. 1 is a functional block diagram of the discharge control device according to the first embodiment of the present invention.
[0024]
In the figure, 31 is a drive motor as an electric machine having a rotor and a stator (not shown), and 40 is supplied with a DC current from a battery 14 as a DC power supply, generates an AC current, and supplies the AC to the drive motor 31. An inverter 17, a capacitor disposed between the battery 14 and the inverter 40, 91 a voltage command value generation processing means for generating a voltage command value for driving the drive motor 31, 68 a voltage command value A pulse width conversion unit serving as a pulse width conversion processing unit for generating a pulse width modulation signal based on the value and supplying the pulse width modulation signal to the inverter 40; When the supply is cut off, a predetermined harmonic is used as a pulse width modulation signal.
[0025]
FIG. 2 is a conceptual diagram of a vehicle drive device according to the first embodiment of the present invention, FIG. 3 is a block diagram of a discharge control device according to the first embodiment of the present invention, and FIG. 4 is a first embodiment of the present invention. 5 is a main flowchart showing the operation of the discharge control device according to the first embodiment, FIG. 5 is a diagram showing a subroutine of a discharge control end determination process according to the first embodiment of the present invention, and FIG. 7 is a flowchart illustrating the operation of the drive motor control device, FIG. 7 is a waveform diagram of the dq axis voltage according to the first embodiment of the present invention, and FIG. 8 is a failure of the voltage sensor according to the first embodiment of the present invention. FIG. 9 is a waveform diagram of the dq-axis actual voltage when the dq-axis actual voltage is generated in the first embodiment of the present invention, and FIG. Drive motor according to the first embodiment of the invention Waveform diagram of click, FIG. 11 is a waveform diagram of the capacitor voltage in the first embodiment of the present invention. 7, the horizontal axis represents time, the vertical axis represents d-axis voltage Vdh and q-axis voltage Vqh, and in FIG. 8, the horizontal axis represents time, and the vertical axis represents d-axis actual voltage Vdr and q-axis actual voltage Vqr. In FIG. 9, the horizontal axis represents time, the vertical axis represents the d-axis actual current idr and the q-axis actual current iqr, and in FIG. 10, the horizontal axis represents time, the vertical axis represents the drive motor torque TM, and FIG. The horizontal axis represents time, and the vertical axis represents capacitor voltage.
[0026]
In the figure, reference numeral 10 denotes a drive motor control device functioning as a computer in accordance with various programs, data, and the like. Reference numeral 31 denotes a drive motor as an electric machine. As the drive motor 31, a DC brushless drive motor is used. The drive motor 31 includes a rotor (not shown) rotatably disposed and a stator disposed radially outward from the rotor. The rotor includes a rotor core attached to a shaft (not shown) of the drive motor 31 and permanent magnets disposed at a plurality of positions in a circumferential direction of the rotor core, for example, at 12 positions in a circumferential direction of the rotor core. Permanent magnets are arranged with the north pole and the south pole alternately facing the outer peripheral surface, and six magnetic pole pairs are formed.
[0027]
The stator includes a stator core (not shown) and U-phase, V-phase, and W-phase stator coils 11 to 13 wound around the stator core. The teeth are formed so as to protrude in the direction.
[0028]
In order to drive the electric motor by driving the drive motor 31, a battery 14 as a DC power supply and a DC current are supplied from the battery 14, and the DC current is converted into a U-phase as an AC current, An inverter 40 that converts the currents into V-phase and W-phase currents Iu, Iv, and Iw is provided, and the currents Iu, Iv, and Iw of each phase are supplied to the drive motor 31, that is, to the stator coils 11 to 13, respectively. .
[0029]
To this end, the inverter 40 includes six transistors Tr1 to Tr6 as switching elements, receives a drive signal SG1 from the drive motor control device 10, and selectively turns on / off each of the transistors Tr1 to Tr6. , Currents Iu, Iv, Iw of the respective phases. Note that a transistor module in which a pair of transistors are modularized, an IPM including a drive circuit, or the like can be used as the inverter 40.
[0030]
A smoothing capacitor 17 is provided between the inverter 40 and the battery 14 in parallel with the inverter 40, and the capacitor 17 stores an electric charge corresponding to the capacitance. An ignition switch 18 is provided between the capacitor 17 and the battery 14 for turning on / off the power of the electric vehicle.
[0031]
Then, a resolver 43 as a magnetic pole position detecting unit is attached to the shaft of the drive motor 31, and the magnetic pole position θ of the rotor is detected by the resolver 43. In the present embodiment, a resolver 43 is used as the magnetic pole position detection unit, but a Hall element (not shown) may be used instead of the resolver 43. In this case, the Hall element generates a position detection signal for each predetermined angle in accordance with the rotation of the rotor, and a magnetic pole position detection circuit (not shown) receives the position detection signal and outputs a signal of the position detection signal. The magnetic pole position θ is detected based on the combination of the levels.
[0032]
Incidentally, a current detecting device 44 is provided to control the currents Iu, Iv, Iw of each phase. The current detection device 44 includes current sensors 33 to 35 as current detection units for detecting currents Iu, Iv, and Iw of each phase on lead wires of the stator coils 11 to 13. The detected currents, that is, the detected currents iu, iv, iw are sent to the drive motor control device 10.
[0033]
Since the stator coils 11 to 13 are star-connected, when the current values of two phases of each phase are determined, the current values of the remaining one phase are also determined. Therefore, for example, a current sensor is provided only in the stator coils 11 and 12, the detection currents iu and iv are detected by the current sensors, and the detection current iw of the current Iw which is the current of the remaining one phase is calculated. You can also.
[0034]
In order to detect the voltage of the battery 14, that is, the DC voltage Vdc, a battery sensor 21 as a DC voltage detecting unit is disposed adjacent to the battery 14, and the voltage on the inlet side of the inverter 40, that is, the inverter voltage In order to detect Vin, a voltage sensor 22 as an inverter voltage detector is disposed adjacent to the capacitor 17, and the DC voltage Vdc and the inverter voltage Vin detected by the battery sensor 21 and the voltage sensor 22 are used to control the drive motor. It is sent to the device 10. Note that the battery sensor 21 can be removed, and the inverter voltage Vin detected by the voltage sensor 22 can be used as a DC voltage. Further, since the voltage sensor 22 is disposed adjacent to the capacitor 17, the voltage of the capacitor 17, that is, the capacitor voltage is represented by the inverter voltage Vin.
[0035]
The drive motor control device 10 includes a CPU, a recording device, and the like (not shown). The drive motor rotation speed calculation processing means (not shown) of the drive motor control device 10 performs a drive motor rotation speed calculation process, and sets the magnetic pole position θ. The rotation speed of the drive motor 31, that is, the drive motor rotation speed NM is calculated based on this. Further, a vehicle speed detection processing unit (not shown) of the drive motor control device 10 performs a vehicle speed detection process, detects a vehicle speed V corresponding to the drive motor rotation speed NM, and outputs the detected vehicle speed V to the entire electric vehicle. It is sent to a vehicle control device (not shown) that performs control.
[0036]
A command value generator of the vehicle control device calculates a vehicle required torque based on the vehicle speed V and an accelerator opening α detected by an accelerator sensor (not shown), and a drive motor torque TM corresponding to the vehicle required torque. Motor target torque TM representing the target value of ^* And the drive motor target torque TM ^* To the drive motor control device 10.
[0037]
By the way, in the drive motor control device 10, the d axis is set in the direction of the magnetic pole pair of the rotor (magnetic flux direction), and the direction perpendicular to the d axis (90 degrees in the forward rotation direction of the drive motor 31 with respect to the d axis). Feedback control is performed on a dq-axis model in which the q-axis is respectively taken in the direction in which the head is advanced. To this end, a drive motor control processing unit (not shown) of the drive motor control device 10 performs a drive motor control process and outputs the drive motor target torque TM. ^* Is read, the d-axis current command value id representing the d-axis component of the vector-displayed current command value is is referred to with reference to the current command value map recorded in the recording device. ^* , And a q-axis current command value iq representing a q-axis component ^* To determine.
[0038]
The three-phase / two-phase converter 61 as the first conversion processing means of the drive motor control device 10 performs the three-phase / two-phase conversion processing as the first conversion processing, and detects the detection currents iu, iv, iw and the magnetic poles. The position θ is read and converted into d-axis current id and q-axis current iq as predetermined axis currents.
[0039]
Further, the d-axis current id and the q-axis current iq are sent to subtractors 62 and 63 as feedback processing means, and the subtracters 62 and 63 perform feedback processing, and execute the d-axis current id and the d-axis current command. Value id ^* D-axis current deviation Δid representing the current deviation from the above, and the q-axis current iq and the q-axis current command value iq ^* The current deviations Δid and Δiq are sent to the current feedback control section 64 as current feedback control processing means and first axis voltage command value generation processing means. Thus, the d-axis current id and the d-axis current command value id ^* And the q-axis current iq and the q-axis current command value iq ^* Is performed based on the feedback control.
[0040]
The current feedback control unit 64 performs a current feedback control process and a first shaft voltage command value generation process, and based on the current deviations Δid and Δiq, a d-axis voltage command value vd as a shaft voltage command value. ^* And q-axis voltage command value vq ^* And the d-axis voltage command value vd ^* And q-axis voltage command value vq ^* To the two-phase three-phase converter 67 as the second conversion processing means and the first phase voltage command value generation processing means. The d-axis voltage command value vd ^* And q-axis voltage command value vq ^* Constitutes a first voltage command value.
[0041]
Subsequently, the two-phase / three-phase converter 67 performs two-phase / three-phase conversion as a second conversion process and a first phase voltage command value generation process, and obtains the d-axis voltage command value vd ^* , Q-axis voltage command value vq ^* And the d-axis voltage command value vd based on the ^* And q-axis voltage command value vq ^* Is a voltage command value vu of each phase as a phase voltage command value. ^* , Vv ^* , Vw ^* And the voltage command value vu ^* , Vv ^* , Vw ^* Is sent to a pulse width conversion unit 68 as a pulse width conversion processing means. The pulse width conversion unit 68 performs a pulse width conversion process and outputs the voltage command value vu of each phase. ^* , Vv ^* , Vw ^* And generating a pulse width modulation signal Su, Sv, Sw of each phase based on the DC voltage Vdc detected by the battery sensor 21, and using the pulse width modulation signals Su, Sv, Sw as a drive signal SG1 to the inverter 40. send. The voltage command value vu of each phase ^* , Vv ^* , Vw ^* Forms a second voltage command value.
[0042]
As a result, the currents Iu, Iv, Iw of each phase are supplied to the stator coils 11 to 13 as described above. In this manner, the electric vehicle can be driven by driving the drive motor 31. The current feedback control unit 64 and the two-phase / three-phase converter 67 constitute a voltage command value generation processing unit 91 (FIG. 1).
[0043]
By the way, when the running of the electric vehicle is completed and the ignition switch 18 is turned off, the supply of current from the battery 14 to the inverter 40 is cut off in conjunction therewith, and the driving of the drive motor 31 is stopped. At this time, the electric charge corresponding to the capacitance is accumulated in the capacitor 17, and the electric power of the drive motor control device 10 is turned off while the electric charge is accumulated in the capacitor 17, and the transistor Tr1 is turned off. When each of the drive signals SG1 sent to the transistors Tr6 to Tr6 transitions to an uncontrolled state transiently, the transistors Tr1 to Tr6 are turned on, a short-circuit current flows, and the durability of the drive motor control device 10 is reduced. is there.
[0044]
Therefore, a discharge control device is provided, and the capacitor 17 is discharged by the discharge control device.
[0045]
By the way, since the electric circuit constituting the drive motor 31 mainly has an inductance component composed of the stator coils 11 to 13, when a high frequency harmonic is sent to the drive motor 31, a high impedance is generated.
[0046]
Therefore, when the supply of the current from the battery 14 to the inverter 40 is interrupted, the pulse width conversion unit 68 sets the harmonics as pulse width modulation signals Su, Sv, Sw. For this purpose, switches Sw1 and Sw2 which are interlocked and switched between the current feedback control unit 64 and the two-phase / three-phase converter 67 are provided, and the harmonics as harmonic generation processing means are provided via the switches Sw1 and Sw2. A wave generator 69 is connected to the two-phase to three-phase converter 67. When the switches Sw1 and Sw2 are set to the first state, the current feedback control unit 64 and the two-phase to three-phase converter 67 are connected. When the switches Sw1 and Sw2 are set to the second state, harmonic generation occurs. The converter 69 and the two-phase to three-phase converter 67 are connected.
[0047]
In this case, first, a discharge control processing unit (not shown) of the drive motor control device 10 performs a discharge control process. When the ignition switch 18 is turned off, the switches Sw1 and Sw2 are set to the second state, and the harmonics The second shaft voltage command value generation processing means (not shown) of the harmonic generator 69 performs a second shaft voltage command value generation process, and outputs a predetermined harmonic as a shaft voltage command value. Va is generated and applied to the two-phase to three-phase converter 67.
[0048]
As shown in FIG. 7, the harmonic Va includes a high-frequency d-axis voltage Vdh and a high-frequency q-axis voltage Vqh. When the application of the harmonic Va to the two-phase to three-phase converter 67 is started, The amplitude is progressively increased and then made constant.
[0049]
At this time, if the voltage sensor 22 has not failed, the amplitude gradually decreases as the capacitor 17 discharges. Even if the voltage sensor 22 has failed, the d-axis actual voltage Vdr and the d-axis actual voltage Vqr are determined by determining the amplitude as the command amplitude based on the preset value as shown in FIG. Has a naturally small amplitude as shown in FIG.
[0050]
Next, the discharge control end determination processing means of the discharge control processing means performs discharge control end determination processing, determines whether or not the discharge of the capacitor 17 has been completed. When the discharge is completed, the discharge control processing means While setting Sw1 and Sw2 in the first state, an instruction is sent to the harmonic generator 69, and the harmonic generator 69 ends the application of the harmonic Va to the two-phase to three-phase converter 67. Accordingly, as shown in FIG. 7, the amplitudes of the d-axis voltage Vdh and the q-axis voltage Vqh are gradually reduced.
[0051]
As described above, since the harmonic Va is applied to the two-phase / three-phase converter 67, the harmonic is transmitted from the two-phase / three-phase converter 67 to the pulse width converter 68, and the voltage command value vu of each phase is applied. ^* , Vv ^* , Vw ^* And the harmonics are sent from the pulse width conversion unit 68 to the inverter 40 as the pulse width modulation signals Su, Sv, Sw of each phase, and the harmonics are added to the currents Iu, Iv, Iw of each phase generated by the inverter 40. Ingredients will be included. Therefore, high impedance is generated in the stator coils 11 to 13, and the currents Iu, Iv, Iw are consumed as Joule heat.
[0052]
As a result, the actual voltage applied to the drive motor 31 on the dq axis model, that is, the dq axis actual voltage changes as shown in FIG. In this case, the amplitudes of the d-axis actual voltage Vdr and the q-axis actual voltage Vqr constituting the d-q-axis actual voltage increase as the amplitudes of the d-axis voltage Vdh and the q-axis voltage Vqh gradually increase, After that, it is attenuated as the capacitor 17 is discharged.
[0053]
Further, the actual current on the dq-axis model supplied to the drive motor 31, that is, the dq-axis actual current changes as shown in FIG. 9. The dq-axis actual current is represented by a d-axis actual current idr and a q-axis actual current iqr, and is calculated by three-phase to two-phase conversion of the detected currents iu, iv, iw by the three-phase to two-phase converter 61. These are the d-axis current id and the q-axis current iq.
[0054]
The amplitudes of the d-axis actual current idr and the q-axis actual current iqr increase as the amplitudes of the d-axis voltage Vdh and the q-axis voltage Vqh gradually increase, and thereafter, as the capacitor 17 is discharged. Attenuate.
[0055]
Further, the drive motor torque TM generated by the drive motor 31 changes as shown in FIG. The drive motor torque TM increases as the amplitudes of the d-axis voltage Vdh and the q-axis voltage Vqh gradually increase, and thereafter attenuates as the capacitor 17 is discharged.
[0056]
Then, the capacitor voltage changes as shown in FIG. 10 and becomes lower as time passes.
[0057]
As described above, since the harmonic Va is generated as the shaft voltage command value, the current Iu, Iv, Iw of each predetermined phase can be supplied to the drive motor 31. Therefore, the electric charge accumulated in the capacitor 17 can be consumed in the drive motor 31, and the capacitor 17 can be reliably discharged. In addition, since the drive motor torque TM generated by the drive motor 31 also includes harmonics and cancels the positive value and the negative value, the rotor of the drive motor 31 remains stationary due to inertia. Therefore, the drive motor 31 is not driven, and no rotation is generated by the drive motor 31.
[0058]
Further, since the harmonic Va is generated as the shaft voltage command value, the current Iu, Iv, Iw of each predetermined phase can be supplied to the drive motor 31 without performing the current feedback control processing. Therefore, even if an abnormality occurs in the current sensors 33 to 35, the capacitor 17 can be reliably discharged. Then, by virtually changing the magnetic pole position θ at a preset cycle, harmonics can be equivalently formed. For example, a fixed value or a virtual value is used as the magnetic pole position θ. Can be. As a result, even if an abnormality occurs in the resolver 43, the capacitor 17 can be reliably discharged.
[0059]
Next, the flowchart of FIG. 4 will be described.
Step S1 The application of the harmonic Va is started.
Step S2: Perform a discharge control end determination process.
Step S3: It is determined whether or not the discharging of the capacitor 17 has been completed. If the discharge of the capacitor 17 has been completed, the process proceeds to step S4, and if not completed, the process returns to step S2.
Step S4: The application of the harmonic Va is ended, and the process is ended.
[0060]
Next, the subroutine of the discharge control end determination process in step S2 in FIG. 4 will be described.
[0061]
First, the discharge control end determination processing means determines whether the voltage sensor 22 has failed, and if the voltage sensor 22 has failed, determines whether a predetermined time has elapsed. After the elapse, a flag for terminating the discharge of the capacitor 17, that is, a discharge control end flag is set.
[0062]
If the voltage sensor 22 has not failed, the discharge control termination determination processing means reads the inverter voltage Vin and determines whether or not the inverter voltage Vin is equal to or less than a predetermined threshold value Vth. If the inverter voltage Vin is equal to or lower than the threshold value Vth, it is determined that the discharge of the capacitor 17 has been completed, and a discharge control end flag is set.
[0063]
Next, the flowchart of FIG. 5 will be described.
Step S2-1: It is determined whether or not the voltage sensor 22 has failed. If the voltage sensor has failed, the process proceeds to step S2-3, and if not, the process proceeds to step S2-2.
Step S2-2: It is determined whether the inverter voltage Vin is equal to or lower than the threshold value Vth. When the inverter voltage Vin is equal to or lower than the threshold Vth, the process proceeds to step S2-4, and when the inverter voltage Vin is higher than the threshold Vth, the process returns.
Step S2-3: It is determined whether a predetermined time has elapsed. If the predetermined time has elapsed, the process proceeds to step S2-4, and if not, the process returns.
Step S2-4: Set the discharge control end flag and return.
[0064]
Next, an operation of the drive motor control device 10 after the application of the harmonic Va is started will be described.
[0065]
First, the drive motor control device 10 determines whether or not the discharge control process is being performed. If the discharge control process is being performed, the drive motor control device 10 determines whether or not the voltage sensor 22 has failed. In this case, the preset voltage value is set to an applied voltage that becomes the d-axis voltage Vdh and the q-axis voltage Vqh. If the voltage sensor 22 has not failed, the drive motor control device 10 sets the inverter voltage Vin to the applied voltage.
[0066]
Subsequently, the drive motor control device 10 generates an applied voltage as a harmonic voltage command and sends it to the harmonic generator 69.
[0067]
Next, the flowchart of FIG. 6 will be described.
Step S11: It is determined whether or not the discharge control process is being performed. If the discharge control process has been performed, the process proceeds to step S13; otherwise, the process proceeds to step S12.
Step S12: A normal current control process is performed, and the process ends.
Step S13: It is determined whether the voltage sensor 22 has failed. If the voltage sensor 22 has failed, the process proceeds to step S15, and if not, the process proceeds to step S14.
Step S14: Make the inverter voltage Vin an applied voltage.
Step S15 A predetermined voltage value is set as an applied voltage.
Step S16: Generate a harmonic voltage command and end the process.
[0068]
Next, a second embodiment of the present invention will be described. In addition, about what has the same structure as 1st Embodiment, the description is abbreviate | omitted by attaching | subjecting the same code | symbol, The effect of the invention by having the same structure uses the effect of the same embodiment. .
[0069]
FIG. 12 is a block diagram of a discharge control device according to the second embodiment of the present invention.
[0070]
In this case, switches Sw11 to Sw13 that are interlocked and switched between a two-phase to three-phase converter 67 as a second conversion processing unit and a pulse width conversion unit 68 as a pulse width conversion processing unit are provided. A harmonic generator 69 as harmonic generation processing means is connected to the pulse width conversion unit 68 via the switches Sw11 to Sw13. When the switches Sw11 to Sw13 are placed in the first state, the two-phase / three-phase converter 67 and the pulse width converter 68 are connected. When the switches Sw11 to Sw13 are placed in the second state, harmonic generation occurs. The device 69 and the pulse width converter 68 are connected.
[0071]
Discharge control processing means (not shown) of the drive motor control device 10 (FIG. 2) performs discharge control processing. When the ignition switch 18 is turned off, the switches Sw11 to Sw13 are set to the second state, and harmonics are set. An instruction is sent to the generator 69, and the second phase voltage command value generation processing means (not shown) of the harmonic generator 69 performs a second phase voltage command value generation process, and generates a harmonic Va as a phase voltage command value. It is generated and applied to the pulse width converter 68.
[0072]
In this case, the harmonic Va includes high-frequency voltages Vuh, Vvh, and Vwh of each phase, and when the application of the harmonic Va to the pulse width conversion unit 68 is started, the amplitude is gradually increased. Be constant.
[0073]
Next, the discharge control termination determination processing unit of the discharge control processing unit performs a discharge control termination determination process, determines whether or not the discharge of the capacitor 17 is completed. When the discharge is completed, the discharge control processing unit switches the switch Sw11. Sw13 is set to the first state, an instruction is sent to the harmonic generator 69, and the application of the harmonic Va is ended. Accordingly, the amplitudes of the voltages Vuh, Vvh, Vwh of each phase are gradually reduced.
[0074]
As described above, the harmonic Va is applied as a phase voltage command value to the pulse width conversion unit 68, so that the harmonics are transmitted from the pulse width conversion unit 68 to the inverter 40 as the pulse width modulation signals Su, Sv, Sw of each phase. As a result, the currents Iu, Iv, Iw of each phase generated by the inverter 40 include harmonic components. Therefore, high impedance is generated in the stator coils 11 to 13, and the currents Iu, Iv, Iw are consumed as Joule heat.
[0075]
Also, a pulse pattern corresponding to the voltage Vuh, Vvh, Vwh of each phase is set in advance in the pulse width conversion unit 68, and the voltage Vuh, Vvh, Vwh of each phase is output by directly outputting the pattern. It can also be generated.
[0076]
It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.
[0077]
【The invention's effect】
As described above in detail, according to the present invention, in a discharge control device, an electric machine including a rotor and a stator, and a DC current is supplied from a DC power supply to generate an AC current, and And a capacitor disposed between the DC power supply and the inverter, a voltage command value generation processing means for generating a voltage command value for driving the electric machine, and a voltage command value. Pulse width conversion processing means for generating a pulse width modulation signal and supplying the pulse width modulation signal to the inverter.
[0078]
When the supply of current from the DC power supply to the inverter is interrupted, the pulse width conversion processing means uses a predetermined harmonic as a pulse width modulation signal.
[0079]
In this case, when the supply of the current from the DC power supply to the inverter is interrupted, a predetermined harmonic is converted into a pulse width modulation signal, so that an AC current can be supplied to the electric machine.
[0080]
Therefore, the electric charge accumulated in the capacitor can be consumed in the electric machine, and the capacitor can be reliably discharged.
[0081]
In addition, since the drive motor torque generated by the electric machine also includes a predetermined harmonic, the rotor of the electric machine remains stationary due to inertia. Therefore, the electric machine is not driven, and no rotation is generated by the electric machine.
[0082]
Further, since the predetermined harmonic is a pulse width modulation signal, an alternating current can be supplied to the electric machine without performing the current feedback control process. Therefore, even if an abnormality occurs in the current sensor, the magnetic pole position detection unit, or the like, the capacitor can be reliably discharged.
[Brief description of the drawings]
FIG. 1 is a functional block diagram of a discharge control device according to a first embodiment of the present invention.
FIG. 2 is a conceptual diagram of a vehicle drive device according to the first embodiment of the present invention.
FIG. 3 is a block diagram of a discharge control device according to the first embodiment of the present invention.
FIG. 4 is a main flowchart showing an operation of the discharge control device according to the first embodiment of the present invention.
FIG. 5 is a diagram illustrating a subroutine of a discharge control end determination process according to the first embodiment of the present invention.
FIG. 6 is a flowchart illustrating an operation of the drive motor control device according to the first embodiment of the present invention.
FIG. 7 is a waveform chart of dq-axis voltages according to the first embodiment of the present invention.
FIG. 8 is a waveform diagram of dq-axis actual voltages when the voltage sensor according to the first embodiment of the present invention fails.
FIG. 9 is a waveform diagram of a dq-axis actual current when a dq-axis actual voltage is generated in the first embodiment of the present invention.
FIG. 10 is a waveform diagram of a drive motor torque according to the first embodiment of the present invention.
FIG. 11 is a waveform diagram of a capacitor voltage according to the first embodiment of the present invention.
FIG. 12 is a block diagram of a discharge control device according to a second embodiment of the present invention.
[Explanation of symbols]
10 Drive motor control device
14 Battery
17 Capacitor
31 Drive motor
40 inverter
64 Current feedback control unit
67 Two-phase three-phase converter
68 pulse width converter
69 Harmonic generator
91 Voltage command value generation processing means

Claims (7)

An electric machine having a rotor and a stator, a DC current supplied from a DC power supply, an inverter for generating an AC current and supplying the electric machine, and a capacitor disposed between the DC power supply and the inverter Voltage command value generation processing means for generating a voltage command value for driving the electric machine, and pulse width conversion processing means for generating a pulse width modulation signal based on the voltage command value and supplying the pulse width modulation signal to the inverter. And a pulse width conversion processing unit, wherein when the supply of current from the DC power supply to the inverter is interrupted, a predetermined harmonic is used as a pulse width modulation signal. 2. The discharge control device according to claim 1, further comprising a current feedback control processing unit that generates a shaft voltage command value based on a current deviation between a current supplied to the electric machine and a current command value. 3. 3. The discharge control device according to claim 1, further comprising: a shaft voltage command value generation processing unit configured to generate a predetermined harmonic as a shaft voltage command value when supply of current from the DC power supply to the inverter is interrupted. 4. The discharge control device according to claim 2, further comprising a conversion processing unit configured to convert the shaft voltage command value into a phase voltage command value. 5. A phase voltage command value generation processing means for generating a predetermined harmonic as a phase voltage command value of each phase of the coil when supply of current from the DC power supply to the inverter is interrupted. Discharge control device. A DC current is received from a DC power supply, an AC current is generated and supplied to the electric machine, a voltage command value for driving the electric machine is generated, and a pulse width modulation signal is generated based on the voltage command value. And supplying a predetermined harmonic to the pulse width modulation signal when the supply of current from the DC power supply to the inverter is interrupted. The computer functions as voltage command value generation processing means for generating a voltage command value for driving the electric machine, and pulse width conversion processing means for generating a pulse width modulation signal based on the voltage command value and supplying the signal to the inverter. The pulse width conversion processing means uses a predetermined harmonic as a pulse width modulation signal when the supply of current from the DC power supply to the inverter is interrupted.

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