JP2005033932A - Motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform proper treatment for torque generated by a motor, in the case of stopping the power supply to the motor. <P>SOLUTION: At drive stoppage (step S31) of a three-phase motor wherein a drive stop signal is inputted, this controller puts it in active short state ( an upper switching element: off, a lower switching element: on) (steps S3 and S4) in case that the rotational speed of a three-phase AC motor is not less than ωeth, and then, when the rotational speed drops to ωeth_1 or under, this puts it in all off state ( the upper switching element :off, the lower switching element :off)(step S6). In the case that the rotational speed at stoppage of the three-phase AC motor is not more than ωeth, this puts it in all off state(steps S3 and S4), and then, when the rotational speed comes to ωeth_u, this puts it in active state (steps S7 and S4). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a motor control device that controls, for example, a motor that is mounted on an electric vehicle or the like and generates a driving force of the electric vehicle.

  Conventionally, as a technique for controlling a three-phase AC motor, one described in Patent Document 1 below is known.

In this patent document 1, when it is detected that the three-phase terminal of the motor tries to generate an abnormally high voltage, all the switching elements of the upper arm of the inverter are turned off and all the switching elements of the lower arm are turned on. State. As a result, conventionally, the three-phase terminals of the motor are short-circuited to suppress the generation of a high voltage.
Japanese Patent Application Laid-Open No. 2002-101689

  Incidentally, in recent years, IPM (Interior Permanent-magnet) motors have been widely used for reasons such as efficiency. However, when the above-described conventional technology is applied to an IPM motor and the three-phase terminals of the IPM motor are short-circuited, the magnitude of torque differs greatly between the high rotation range and the low rotation range. Torque (brake torque) in a direction that prevents the rotation of the IPM motor is generated over the entire area.

  Here, when the three-phase terminal is short-circuited in the high rotation region, the torque is small, and the state is close to free run. However, when the three-phase terminal is short-circuited in the low rotation region, there is a characteristic that once the rotation speed approaches 0 from the high rotation region side, the magnitude of the torque suddenly increases.

  Due to these characteristics, when the three-phase terminal is short-circuited in the high rotation region of the IPM motor, the IPM motor does not change rapidly even if it is in a free-run state without a sudden change in the rotation speed. When the three-phase terminals are short-circuited in the region, there is a problem that a large brake torque is generated and a rapid deceleration of the rotational speed of the IPM motor occurs.

  Therefore, the present invention has been proposed in view of the above-described circumstances, and motor control that can perform appropriate processing on the torque generated by the AC motor when power supply to the AC motor is stopped. An object is to provide an apparatus.

  The present invention drives an upper switching element group connected to a positive terminal of a power source supplied to an AC motor and a lower switching element group connected to a negative terminal of the power source to apply an AC voltage to the AC motor. When the drive of the AC motor is stopped, the motor control device inputs a rotation speed signal indicating the rotation speed of the AC motor by the input means, and controls the upper switching element group and the lower switching element group by the control means. Then, the torque of the AC motor is controlled. At this time, in the control means, when the rotational speed of the AC motor input by the input means is equal to or higher than the first rotational speed, all of the switching element groups in either the upper switching element group or the lower switching element group are When the other switching element group is turned off and all the other switching element groups are shut off, and the rotational speed of the AC motor input by the input means is equal to or lower than the second rotational speed, the upper switching element group and the lower switching element group The above-mentioned problem is solved by putting all the switching element groups into a cut-off state.

  The present invention also includes an upper switching element group connected to a positive terminal of a power supply that is mounted on a vehicle and generates a driving force of the vehicle by generated torque, and is connected to a negative terminal of the power supply. The motor control device that drives the side switching element group and applies an AC voltage to the AC motor, and determines whether the vehicle is stopped by the input means when the vehicle is held in a stopped state. A signal is inputted and the upper switching element group and the lower switching element group are controlled by the control means to control the torque of the AC motor. At this time, when it is determined that the vehicle is in a stopped state based on the signal input by the input unit, the control unit conducts all of the switching element group of either the upper switching element group or the lower switching element group. The above-described problem is solved by setting the other switching element group to the cut-off state while setting the state.

  According to the motor control device of the present invention, when the rotation of the AC motor is stopped, the rotation speed of the AC motor changes, and the AC motor is greatly affected by the state of the upper switching element group and the lower switching element group. Even when torque is generated, the upper switching element group and the lower switching element group can be in an appropriate state according to the rotation speed, and the AC motor generates over the entire rotation speed of the AC motor. Since the torque is kept at a very small value, it is possible to appropriately process the torque generated by the AC motor.

  Further, according to another motor control device of the present invention, when the vehicle is stopped, the upper switching element group and the lower switching element group are set in an appropriate state so that the AC motor generates a brake torque. Since the vehicle can be held in a stopped state, an appropriate process can be performed on the torque generated by the motor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
The present invention is applied to, for example, a motor control device configured as shown in FIG.

[Configuration of motor controller]
This motor control device controls and drives the three-phase AC motor 1 to be controlled according to the rotational speed of the three-phase AC motor 1. In the three-phase AC motor 1, each current value supplied to the U phase, the V phase, and the W phase is controlled, whereby each current flowing through the internal coil is controlled to control the torque. In this example, the three-phase AC motor 1 is a permanent magnet synchronous motor, and includes an IPM (Interior Permanent-magnet) motor including a rotor having an internally embedded magnet structure and a stator having a concentrated winding structure. It is.

  The motor control device is supplied with a torque command Te * for controlling the torque of the three-phase AC motor 1 from the outside, performs various calculations for generating the torque of the torque command Te *, and performs the three-phase AC motor 1. To control the current supplied to the.

  When driving the three-phase AC motor 1 according to the torque command Te *, the motor control device detects the U-phase motor current iu and the V-phase motor current iv supplied to the three-phase AC motor 1 by the current sensor 2. To the three-phase / dq conversion unit 3. Further, the rotation angle θm of the three-phase AC motor 1 is detected by inputting the rotation angle of the three-phase AC motor 1 by the rotation angle sensor (PS) 4 and sent to the phase / speed calculation unit 5.

  The phase / speed calculation unit 5 calculates the rotation speed ωe of the three-phase AC motor 1 based on the rotation angle θm, calculates the voltage phase θe, and sends a signal indicating the rotation speed ωe to the torque control unit 7. A signal indicating the voltage phase θe is sent to the three-phase / dq converter 3.

  The three-phase / dq conversion unit 3 inputs the voltage phase θe of the dq coordinate system as viewed from the three-phase AC coordinate system, and also inputs the U-phase motor current iu and the V-phase motor current iv. The currents iu, iv, iw (= −iu−iv) are converted into the d-axis current value id and the q-axis current value iq, which are actual currents in the dq coordinate system that is the rotation orthogonal coordinate system, and are sent to the current control unit 6. .

  On the other hand, when the torque command Te * and the rotational speed (electricity) ωe of the three-phase AC motor 1 are given from the outside, the torque control unit 7 sets the d-axis current command id * and the target d-axis current value. A q-axis current command iq * of the q-axis current value iq is obtained and sent to the current control unit 6 and the non-interference control unit 8.

  The current control unit 6 is supplied with the voltage value Vdc indicating the voltage value of the power supply 13, the d-axis current command id * and the q-axis current command iq * from the torque control unit 7, and the d-axis current from the three-phase / dq conversion unit 3. When the value id and the q-axis current value iq are supplied, the d-axis voltage command value vd * for matching the d-axis current value id with the d-axis current command value id *, and the q-axis current value iq as the q-axis current command A q-axis voltage command value vq * for matching with the value iq * is calculated and sent to the adder 9.

  When the d-axis current command id * and the q-axis current command value iq * are sent from the torque control unit 7, the non-interference control unit 8 is a voltage component used to guarantee the interference term between the d-axis and the q-axis. The axis compensation voltage Vd_cmp and the q axis compensation voltage Vq_cmp are calculated.

  The d-axis compensation voltage Vd_cmp is added to the d-axis voltage command value vd * by the adder 9 and sent from the adder 9 to the dq / 3-phase converter 10 as the d-axis current command value vdo *. The compensation voltage Vq_cmp is added to the q-axis voltage command value vq * by the adder 9 and sent from the adder 9 to the dq / 3-phase converter 10 as the q-axis current command value vqo *.

  The dq / 3-phase conversion unit 10 is supplied with the d-axis current command value vdo * and the q-axis current command value vqo * from the adder 9, and is supplied with the voltage phase θe from the phase / speed calculation unit 5. Based on θe, the d-axis current command value vdo * and the q-axis current command value vqo * are converted into a U-phase voltage command value vu *, a V-phase voltage command value vv *, and a W-phase voltage command value vw * in a three-phase coordinate system. Convert. Then, the U-phase voltage command value vu *, the V-phase voltage command value vv *, and the W-phase voltage command value vw * are sent to the PWM generator 11.

  The PWM generator 11 generates PWM signals Vu, Vul, Vvu, Vvl, Vwu, and Vwl based on the U-phase voltage command value vu *, the V-phase voltage command value vv *, and the W-phase voltage command value vw *. Output to the power converter 12. This PWM signal is a signal for driving on and off the first transistor Tr1 to the second transistor Tr2 constituting the upper switching element group 22 of the power converter 12 described later.

  As shown in FIGS. 2 and 3, the power converter 12 has an upper switching element group 22 connected to the positive terminal of the power source 13 and a negative terminal of the power source 13 through a smoothing capacitor 21. And a lower switching element group 23 connected thereto. The power converter 12 includes a first transistor Tr1 and a second transistor Tr2 connected to the U phase of the three-phase AC motor 1, and a third transistor Tr3 and a fourth transistor connected to the V phase of the three-phase AC motor 1. The transistor Tr4 includes a fifth transistor Tr5 and a sixth transistor Tr6 connected to the W phase of the three-phase AC motor 1.

  In such a power converter 12, the PWM signal from the PWM generator 11 is supplied to the gate terminals of the first transistor Tr1 to the sixth transistor Tr6, whereby the first transistor Tr1 to the sixth transistor Tr6 are turned on and off. The state is controlled. Thereby, in the power converter 12, the first transistor Tr1 and the second transistor Tr2 generate AC power supplied from the 13 to the U phase of the three-phase AC motor 1, and the third transistor Tr3 and the fourth transistor Tr4 3 AC power supplied to the V phase of the phase AC motor 1 is generated, and AC power supplied to the W phase of the three-phase AC motor 1 is generated by the fifth transistor Tr5 and the sixth transistor Tr6.

  The power converter 12 is connected to a drive stop switching unit 14 that controls the drive stop of the first transistor Tr1 to the sixth transistor Tr6. Although not shown, the power converter 12 includes a state switching circuit that switches on / off states of the first transistor Tr1 to the sixth transistor Tr6 based on a signal from the drive stop switching unit 14.

  As will be described in detail later, the drive stop switching unit 14 normally sets the value of the drive stop signal f_stp to “0” and causes the power converter 12 to switch the power supply 13 on the basis of the PWM signal generated by the PWM generation unit 11. The DC voltage is converted into a three-phase AC voltage and applied to the three-phase AC motor 1. The drive stop switching unit 14 sets the value of the drive stop signal f_stp to “1” when the three-phase AC motor 1 is stopped from the state where the three-phase AC motor 1 is driven and rotated. And the operation of the power converter 12 is controlled.

[Operation of Drive Stop Switching Unit 14]
Next, the operation of the drive stop switching unit 14 in the motor control device described above will be described.

  The drive stop switching unit 14 is supplied with a voltage value Vdc from the voltage sensor 15, a rotation speed ωe from the phase / speed calculation unit 5, and a drive stop signal from an external controller (not shown). As will be described in detail later, the drive stop switching unit 14 generates a drive stop signal f_stp for driving or stopping the operation of the power converter 12 based on each input signal, and stops the operation of the power converter 12. A drive stop method selection signal f_fs for selecting and controlling the state at the time of generation is generated. Thereby, the drive stop switching unit 14 drives or stops the three-phase AC motor 1.

  When driving the power converter 12 based on the PWM signal to drive the three-phase AC motor 1, the drive stop switching unit 14 generates a drive stop signal f_stp having a value of “0” to generate the power converter 12. Send to. As a result, the power converter 12 sends the PWM signals Vuu, Vul, Vvu, Vvl, Vwu, Vwl from the PWM generator 11 to the first transistor Tr1 to the sixth transistor Tr6 and supplies the AC power to the three-phase AC motor 1. Supply.

  On the other hand, when stopping the power converter 12 and stopping the three-phase AC motor 1, the drive stop switching unit 14 generates a drive stop signal f_stp having a value “1” and sends it to the power converter 12. As a result, the power converter 12 sends the PWM signals Vuu, Vul, Vvu, Vvl, Vwu, Vwl from the PWM generation unit 11 to the first transistor Tr1 to the sixth transistor Tr6 to supply AC power to the three-phase AC motor 1. Stop supplying.

  Further, when stopping the three-phase AC motor 1, the drive stop switching unit 14 generates a drive stop method selection signal f_fs indicating a method of stopping the driving of the three-phase AC motor 1. At this time, based on the voltage value Vdc and the rotational speed ωe of the three-phase AC motor 1, the drive stop switching unit 14 shuts off (turns off) all the switching elements of the first transistor Tr1 to the sixth transistor Tr6 as shown in FIG. ) State, or all the switching elements of the upper switching element group 22 are turned off (off) and all the switching elements of the lower switching element group 23 are turned on (on) as shown in FIG. The active short state is determined. The drive stop switching unit 14 generates a drive stop method selection signal f_fs having a value of “0” when the power converter 12 is in the all-off state, and a value when the power converter 12 is in the active short state. Generates a drive stop method selection signal f_fs with “1”.

  Thereby, the drive stop switching part 14 controls the state of the power converter 12, as shown in FIG. The power converter 12 receives data for controlling the states of the upper switching element group 22 and the lower switching element group 23 as shown in FIG. 4 in a memory (not shown) according to a signal input from the drive stop switching unit 14. It shall be remembered.

  That is, when the value of the drive stop signal f_stp is “0”, the power converter 12 receives the PWM signals Vuu, Vul, Vvu, Vvl, Vwu, and Vwl from the PWM generator 11 from the first transistor Tr1 to the first transistor Tr1. The power is supplied to the six-transistor Tr6, and the DC power from the power source 13 is converted into AC power to supply power to the three-phase AC motor 1.

  On the other hand, when the value of the drive stop signal f_stp is “1” and the value of the drive stop method selection signal f_fs is “0”, the power converter 12 enters the all-off state as shown in FIG. Then, power supply to the three-phase AC motor 1 is stopped. In addition, when the value of the drive stop signal f_stp is “1” and the value of the drive stop method selection signal f_fs is “1”, the power converter 12 enters an active short state as shown in FIG. Then, power supply to the three-phase AC motor 1 is stopped.

"Determination process of drive stop method selection signal"
Next, a process when determining the drive stop method selection signal f_fs in the drive stop switching unit 14 that performs the above-described operation will be described.

  First, the condition regarding the rotational speed ωe when the drive stop method selection signal f_fs = 0 is set, that is, when the power converter 12 is set to the all-off state will be described.

The drive stop switching unit 14 needs to stop the current supply to the three-phase AC motor 1 when the power converter 12 is set to the all-off state and the driving of the three-phase AC motor 1 is stopped. Therefore, as a condition that no current flows in the three-phase AC motor 1, the induced voltage by the magnet of the three-phase AC motor 1 is V _{p (0-p),} and the maximum voltage that can be output by the power converter 12 is V _{p_max} . Then, as shown in Equation 1 below,
_{Vp (0-p)} <= _{Vp_max} (Formula 1)
It is necessary to satisfy the condition. That is, when the induced voltage due to the magnetic flux of the magnet is equal to or less than the maximum voltage that can be output by the power converter 12, no current flows through the three-phase AC motor 1. Therefore, the generation of torque of the three-phase AC motor 1 is stopped by realizing this condition.

Here, the induced voltage (phase voltage amplitude) _{Vp (0-p)} due to the magnetic flux of the magnet depends on the rotational speed of the three-phase AC motor 1 as shown in FIG.
V _{p (0−p)} = (2/3) ^1/2 ω _e φ _dm (Formula 2)
It is expressed by Here, ω _e is the rotational speed (electrical angle) of the three-phase AC motor 1, and φ _dm is an induced voltage due to the magnetic flux of the three-phase AC motor 1.

Further, the maximum voltage V _{p_max} that can be output by the power converter 12 is as shown in Equation 3 below.
_{Vp_max} = (1/3) ^1/2 _Vdc (Formula 3)
It is expressed by Here, V _dc is a DC voltage value supplied to the power converter 12 and a value detected by the voltage sensor 15.

Therefore, using the induced voltage (phase voltage amplitude) V _{p (0-p)} due to the magnetic flux of the magnet expressed by Equation 2 and the maximum voltage V _{p_max} that can be output by the power converter 12 expressed by Equation 3, As shown in Equation 4 below, the above Equation 1 is
ω _e ≦ V _dc / {(2) ^1/2 φ _dm } (Formula 4)
It becomes. Therefore, when the rotational speed ωe of the three-phase AC motor 1 sent from the phase / speed calculation unit 5 satisfies the above equation 4, the drive stop switching unit 14 controls the power converter 12 to the all-off state. Torque generation of the three-phase AC motor 1 can be stopped.

For the convenience of the following description, the maximum rotational speed satisfying the above equation 4 is represented by ω _{e_ao} and expressed by the following equation 5. Such a rotational speed ω _{e — ao} is a rotational speed at which the induced voltage due to the magnetic flux of the three-phase AC motor 1 generates a voltage equal to the maximum voltage that can be output by the upper switching element unit 22 and the lower switching element unit 23.

ω _e — _ao = V _dc / {(2) ^1/2 φ _dm } (Formula 5)
Thus, the range of the rotational speed ωe that can stop the torque generation of the three-phase AC motor 1 when the power converter 12 is in the all-off state, that is, the all-off setting region of the rotational speed ωe is shown in FIG. Thus, 0 to _{ωe_ao} . Therefore, the drive stop switch 14, within the rotational speed ωe of _0~ω e_ao, value and outputs a drive stop method selection signal f_fs of "0" to the power converter 12, power converter 12 ol By setting the OFF state, the rotational operation of the three-phase AC motor 1 can be stopped while the torque generation of the three-phase AC motor 1 is suppressed.

  Next, the conditions regarding the rotational speed ωe when the drive stop method selection signal f_fs = 1 is set, that is, when the power converter 12 is brought into the active short state will be described.

  FIG. 7 shows the relationship between the rotational speed ωe and the torque of the three-phase AC motor 1 when the power converter 12 is in an active short state. According to FIG. 7, the torque of the three-phase AC motor 1 is close to 0 in the high rotation speed region where the rotation speed ωe of the three-phase AC motor 1 is high. On the other hand, when the rotational speed ωe of the three-phase AC motor 1 when the power converter 12 is in the active short state approaches 0, the torque of the three-phase AC motor 1 increases and the torque of the three-phase AC motor 1 increases. When the rotational speed ωe is the rotational speed ωe_m, a brake torque that is a negative torque is generated.

Torque T _e in the case of this manner the power converter 12 to activate the short state, as shown in Equation 6 below,
T _e = p {−R (φ _dm ² ) / (L _d ² ) · (1 / ω _e )} (Formula 6)
It becomes. Here, p in the above formula 6 is a pole pairs of the three-phase AC motor 1, R is a phase winding resistance value of the three-phase AC motor 1, L _d is inductance.

Further, when stopping the three-phase AC motor 1 and assuming that the maximum allowable value of the brake torque generated in the three-phase AC motor 1 is _{Te_b} , as shown in Equation 7 below,
T _e ≦ T _{e — b} (Formula 7)
Next, the torque T _e represented by the formula 6, by less than the maximum allowable value T _{E_b} braking torque, driving the 3-phase AC motor 1 without generating excessive torque to the three-phase AC motor 1 Can be stopped.

That is, when the torque T _e expressed by Equation 6 is introduced into Equation 7, the rotational speed ω _e is expressed by Equation 8 below:
ω _e ≧ p {−R (φ _dm ² ) / (L _d ² ) · (1 / T _{e — b} )} (Formula 8)
It becomes. That is, if the minimum rotational speed of the three-phase AC motor 1 that satisfies the above equation 8 is ω _{e_as} , the equation 8 is
ω _{e — as} ≧ p {−R (φ _dm ² ) / (L _d ² ) · (1 / T _{e — b} )} (Formula 9)
It is expressed as shown in

As a result, when the power converter 12 is brought into the active short state from the state where the three-phase AC motor 1 is rotationally driven, the three-phase AC motor 1 is stopped while suppressing the torque generation of the three-phase AC motor 1. The range of the rotation speed _ωe that can be generated, that is, the active short setting region of the rotation speed _ωe is _{equal to} or greater than ω _{e_as} as shown in FIG. Accordingly, the drive stop switching unit 14 outputs the drive stop method selection signal f_fs having a value of “1” to the power converter 12 in the range where the rotational speed _ωe is _{equal to} or higher than ω _{e_as} , and the power converter 12 is in the active short state. Thus, the rotational operation of the three-phase AC motor 1 can be stopped while the torque generation of the three-phase AC motor 1 is suppressed.

  Next, switching operation between the all-off state and the active short state by the drive stop switching unit 14 will be described.

  Here, as shown in FIG. 6, in the range where the rotational speed ωe is represented by the following formula 10, the power converter 12 is in an all-off state or active from the state where the three-phase AC motor 1 is rotationally driven. Even in any of the short states, the rotational operation of the three-phase AC motor 1 can be stopped while the torque generation of the three-phase AC motor 1 is suppressed.

ω _{e_as} ≦ ω _e ≦ ω _{e_ao} (Equation 10)
In contrast, in the drive stop switch 14, and the rotation speed omega _{E_as,} power conversion in the case where the rotational speed ωe which the rotation speed ωeth intermediate value calculated by the phase-velocity calculation unit 5 and the rotation speed omega _{E_ao} high When the rotational speed ωe calculated by the phase / speed calculator 5 is lower than the rotational speed ωeth, the power converter 12 is set to the all-off state.

  As described above, the drive stop switching unit 14 switches the state of the power converter 12 based on the rotational speed ωeth, and then changes the rotational speed ωe of the three-phase AC motor 1 and the DC voltage value supplied to the power converter 12. Based on this, the switching operation is performed between the active short state and the all-off state. That is, in the drive stop switching unit 14, after the active short state or the all-off state is once set, a high torque is applied to the three-phase AC motor 1 by changing the rotation speed or the DC voltage value of the three-phase AC motor 1. The operation | movement which switches the state of the power converter 12 is performed so that it may not generate | occur | produce.

On the other hand, the drive stop switching unit 14 maintains the active short state by setting in advance a rotational speed ωeth_l between _{ωe_as} and ωeth as the rotational speed ωe for switching from the active short state to the all-off state. Set the active short holding area. Further, the drive stop switching unit 14 _presets a rotational speed ωeth_u between _{ωe_ao} and ωeth as the rotational speed ωe for switching from the all-off state to the active short state, thereby maintaining the all-off state. Set the holding area.

  As a result, the drive stop switching unit 14 temporarily changes the state of the power converter 12 to the active short state, and then the rotational speed ωe decreases and exceeds the rotational speed ωeth_l as shown in FIG. If it goes outside, it will be in an all-off state. Further, in the drive stop switching unit 14, after the power converter 12 is once set in the all-off state, as shown in FIG. 6, the rotational speed ωe increases and exceeds the rotational speed ωeth_u, so as to be outside the all-off holding region. When it becomes, it will be in active short state.

  In the drive stop switching unit 14 that performs such an operation, as shown in FIG. 8, first, when a drive stop signal is input from the outside (step S <b> 1), the rotational speed ωe and the phase / speed calculation unit 5 are input. The voltage value Vdc is input from the voltage sensor 15 (step S2), and it is determined whether or not the rotational speed ωe is equal to or lower than the rotational speed ωeth (step S3).

  When the drive stop switching unit 14 determines that the rotational speed ωe is equal to or lower than the rotational speed ωeth, the drive stop signal f_stp and the drive stop method selection signal f_fs both having the value “1” are sent to the power converter 12. Output. Thereby, in the drive stop switching part 14, the power converter 12 is made into an active short state (step S4).

  On the other hand, when the drive stop switching unit 14 determines that the rotation speed ωe is not equal to or less than the rotation speed ωeth, the drive stop signal f_stp having the value “1” and the drive stop method selection signal f_fs having the value “0” are used as the power. Output to the converter 12. Thereby, in the drive stop switching part 14, the power converter 12 is made into an all-off state (step S5).

  After setting the power converter 12 in the active short state, the drive stop switching unit 14 monitors the rotation speed ωe from the phase / speed calculation unit 5 by periodically inputting the rotation speed ωe, for example, and the rotation speed ωe_l_ It is determined whether it is below (step S6). When the drive stop switching unit 14 determines that the rotational speed ωe is not equal to or lower than the rotational speed ωeth_l, the process returns to step S4 to continue the active short state, and when the rotational speed ωe is determined to be equal to or lower than the rotational speed ωeth_l. Returning the processing to step S5, the power converter 12 is switched to the all-off state.

  On the other hand, the drive stop switching unit 14 monitors the power converter 12 by, for example, periodically inputting the rotation speed ωe from the phase / speed calculation unit 5 after setting the power converter 12 to the all-off state. Is greater than or equal to the rotational speed ωeth_u (step S7).

  Then, when it is determined that the rotational speed ωe is equal to or higher than the rotational speed ωeth_u, the drive stop switching unit 14 returns the process to step S4 and switches the power converter 12 to the active short state. On the other hand, if the drive stop switching unit 14 determines that the rotational speed ωe is not equal to or higher than the rotational speed ωeth_u, the rotational speed ωe is “0” in step S8 and the three-phase AC motor 1 is stopped. If the three-phase AC motor 1 has stopped, the process is terminated. If the three-phase AC motor 1 has not stopped, the process returns to step S5 to continue the all-off state.

[Effect of the first embodiment]
As described above in detail, according to the motor control device according to the first embodiment to which the present invention is applied, when the rotation of the three-phase AC motor 1 is stopped, the rotation speed of the three-phase AC motor 1 is rotated. When the speed ωe_as or higher, the power converter 12 is in the active short state, and when the rotational speed of the three-phase AC motor 1 is lower than the rotational speed ωe_ao, the power converter 12 is in the all-off state. The brake torque generated in the three-phase AC motor 1 can be kept at a very small value over the entire rotation speed of the three-phase AC motor 1.

  Therefore, according to this motor control device, for example, when mounted as a motor drive system for an electric vehicle, even if driving of the three-phase AC motor 1 is stopped during high-speed traveling, the three-phase AC motor 1 It is possible to stop the traveling of the vehicle by stopping the three-phase AC motor 1 without generating a large brake torque in a free-run state in which substantially no torque is generated.

  Therefore, according to this motor control device, when the power supply to the three-phase AC motor 1 is stopped, it is possible to appropriately process the torque generated by the three-phase AC motor 1.

  That is, according to this motor control device, when the rotational speed of the three-phase AC motor 1 is a rotational speed ωe1 higher than the rotational speed ωeth, as shown in FIG. When the phase AC motor 1 is stopped (FIG. 9 (a)), the power converter 12 is brought into an active short state, so that only the d-axis current in the negative direction is generated in the three-phase AC motor 1 (FIG. 9 ( c)) The rotational speed of the three-phase AC motor 1 can be reduced with a very small motor torque (FIGS. 9B and 9A).

  Further, according to this motor control device, when the power converter 12 is brought into the active short state, the rotational speed is decreased from the rotational speed ωe1, and the rotational speed of the three-phase AC motor 1 becomes the rotational speed ωeth_l. Even after switching from the active short state to the all-off state at, it is possible to prevent the motor torque from being generated in the low rotational speed region of the three-phase AC motor 1 (FIG. 9A, ( b)).

  On the other hand, FIG. 10 shows simulation results of motor rotation speed (a), motor torque (b), and motor current (c) when the power converter 12 is held in the active short state, and FIG. 11 shows the power converter. The simulation result of motor rotational speed (a), motor torque (b), and motor current (c) when 12 is kept in the all-off state is shown.

  According to FIG. 10, when the rotation speed of the motor is in the high rotation speed region, the simulation result shown in FIG. 9 is obtained, but when the rotation speed of the motor decreases to become the rotation speed ωe_as (FIG. 10 (a)), When the brake torque Te_b is larger than the motor torque in FIG. 9 (FIG. 10B), and when the rotational speed of the motor further decreases to near “0” (FIG. 10A), the motor torque is also applied to FIG. As shown, the brake torque (-Te1) is further increased (FIG. 10B).

  Further, according to FIG. 11, a large brake torque (−Te1) is generated when the power converter 12 is in the all-off state, and the large brake torque continues to be generated until the time when the rotational speed of the motor decreases to ωe_ao. (FIG. 11A).

  Further, according to this motor control device, when the three-phase AC motor 1 is stopped, the power converter 12 is brought into an active short state, and when the rotational speed ωe decreases to the rotational speed ωeth_l, the power converter 12 is brought into an all-off state. Since the switching is performed, it is possible to prevent a large brake torque from being generated in a low rotation region where the rotation speed of the three-phase AC motor 1 is reduced.

  Further, according to this motor control device, when the three-phase AC motor 1 is stopped, the power converter 12 is set to the all-off state, and when the rotational speed ωe becomes the rotational speed ωeth_u, the power converter 12 is set to the active short state. Since the switching is performed, it is possible to prevent a large brake torque from being generated even when the rotational speed of the three-phase AC motor 1 is increased.

  Furthermore, according to this motor control device, since the rotational speed of the three-phase AC motor 1 that switches from the active short state to the all-off state is the rotational speed ωeth_l, the magnetic flux of the three-phase AC motor 1 is converted into the power converter 12. Therefore, it is possible to prevent the brake torque from being generated in the three-phase AC motor 1 due to the fact that it cannot be output.

  Furthermore, according to this motor control device, since the rotational speed of the three-phase AC motor 1 that switches from the all-off state to the active short state is the rotational speed ωeth_u, the torque that is allowed when the three-phase AC motor 1 is stopped is exceeded. Can be prevented.

  Furthermore, according to this motor control device, the rotational speed at which the active short state is switched to the all-off state is set to a rotational speed ωeth_l higher than the rotational speed ωe_as, and the rotational speed at which the all-off state is switched to the active short state is greater than the rotational speed ωe_ao. Since the low rotation speed ωeth_u is set, the switching timing between the active short state and the all-off state can be set to a timing at which the motor torque is not increased. Therefore, according to this motor control device, no matter how the rotational speed of the three-phase AC motor 1 changes after the power supply to the three-phase AC motor 1 is stopped, Torque can be kept at a small value.

[Second Embodiment]
Next, a motor control device according to the second embodiment will be described. In addition, about the part similar to the above-mentioned 1st Embodiment, the detailed description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  As shown in FIG. 12, the motor control device according to the second embodiment includes a power converter 12 ′ and a drive stop switching unit 14 ′ that operate differently from the first embodiment.

  That is, the motor control device according to the second embodiment is mounted on an electric vehicle that travels by the driving force of the three-phase AC motor 1, and the drive stop switching unit 14 ′ has a vehicle in an activated state or a stopped state. An ignition signal IGN indicating the state of the IGN switch, which is a signal indicating whether the vehicle is in a stationary state, and a side brake signal indicating the state of the side brake that holds the vehicle in a stopped state are input. Then, the drive stop switching unit 14 ′ generates a drive control signal f_BRK that controls the state of the power converter 12 ′ based on the ignition signal IGN and the side brake signal, and outputs the drive control signal f_BRK to the power converter 12 ′.

  Thereby, the drive stop switching unit 14 'controls the state of the power converter 12' as shown in FIG. The power converter 12 ′ includes data for controlling the states of the upper switching element unit 22 and the lower switching element unit 23 as shown in FIG. 13 in accordance with the drive control signal input from the drive stop switching unit 14 ′. It is assumed that it is stored in a memory that does not.

  Specifically, the drive stop switching unit 14 ′ receives an ignition signal IGN indicating that the IGN switch is in an off state, or receives a side brake signal indicating that the side brake is operating. Generates a drive control signal f_BRK that puts the power converter 12 ′ into an active short state, and outputs it to the power converter 12 ′. As a result, the power converter 12 'enters an active short state as shown in FIG.

  On the other hand, the drive stop switching unit 14 ′ receives an ignition signal IGN indicating that the IGN switch is in an OFF state, or a case where a side brake signal indicating a state where the side brake is operating is input. In this case, the power converter 12 ′ supplies the PWM signals Vuu, Vul, Vvu, Vvl, Vwu, and Vwl from the PWM generator 11 to the first transistor Tr1 to the sixth transistor Tr6, and the direct current from the power supply 13 is supplied. The power is converted into AC power, and power is supplied to the three-phase AC motor 1.

  Here, when the vehicle is stopped, the rotational speed of the traveling three-phase AC motor 1 is zero. On the other hand, the motor torque when the rotational speed of the three-phase AC motor 1 is near 0 is as shown in FIG. 7 showing the relationship between the torque and the rotational speed when the power converter 12 ′ is in the active short state. When the rotational speed of the three-phase AC motor 1 increases in the positive direction, it suddenly increases in the negative direction. Conversely, when the rotational speed of the three-phase AC motor 1 increases in the negative direction, it suddenly increases in the positive direction.

  Therefore, the three-phase AC motor 1 is in a stable state when the rotational speed, in other words, the vehicle speed is zero. That is, when the three-phase AC motor 1 is in the active short state, the vehicle is in a state where the brake is applied.

[Effects of Second Embodiment]
As described above in detail, according to the motor control device of the second embodiment, when it is determined that the vehicle is in a stopped state, the vehicle is braked only by setting the power converter 12 ′ to the active short state. Can be applied. Therefore, according to this motor control device, the vehicle can be held in a stopped state only by performing simple control on the power converter 12 ′, and energy saving without using the power of the power source 13 can be realized.

  Therefore, according to this motor control device, when the power supply to the three-phase AC motor 1 is stopped, it is possible to appropriately process the torque generated by the three-phase AC motor 1.

  The above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and various modifications can be made depending on the design and the like as long as the technical idea according to the present invention is not deviated from this embodiment. Of course, it is possible to change.

  That is, in the second embodiment, the case where the power converter 12 ′ is actively set in the active short state has been described. However, the power converter 12 ′ may be passively set in the active short state. In this case, the motor control device uses the first transistor Tr1, the third transistor Tr3, and the fifth transistor Tr5 that are in a shielded state (off state) when no signal is applied, and is in a conductive state when no signal is applied. It is necessary to use the second transistor Tr2, the fourth transistor Tr4, and the sixth transistor Tr6 that are turned on. By using such a power converter 12 ', it is possible to set the active short state even when the power supply for controlling the power converter 12' is also stopped.

It is a block diagram which shows the structure of the motor control apparatus which concerns on 1st Embodiment to which this invention is applied. It is a circuit diagram for demonstrating a state when a power converter is set to an active short state. It is a circuit diagram for demonstrating a state when a power converter is set to an all-off state. It is a figure for demonstrating the state of the power converter with respect to the drive stop signal f_stp input into a drive stop switching part, and the drive stop method selection signal f_fs. It is a figure for demonstrating the relationship between the rotational speed of a three-phase alternating current motor, and the induced voltage (phase voltage amplitude) by the magnet of a three-phase alternating current motor. It is a figure which shows the active short possible area | region and all-off possible area | region, active short setting area | region, all-off setting area | region, active short holding area | region, and all-off holding | maintenance area | region with respect to the rotational speed of a three-phase alternating current motor. It is a figure which shows the relationship between the rotational speed of the three-phase alternating current motor at the time of making an electric power converter into an active short state, and the torque which a three-phase alternating current motor generate | occur | produces. In the motor control apparatus which concerns on 1st Embodiment, it is a flowchart which shows the process sequence when controlling the state of a power converter by a drive stop switching part. It is a figure which shows the result of having simulated the operation | movement at the time of switching a power converter from an active short state to an all-off state when stopping rotation of a three-phase AC motor.

  (A) It is a figure which shows the time change of a motor rotational speed.

  (B) It is a figure which shows the time change of a motor torque.

(C) It is a figure which shows the time change of q-axis current and d-axis current.
It is a figure which shows the result of having simulated the operation | movement at the time of hold | maintaining a power converter in an active short state, when stopping rotation of a three-phase alternating current motor.

  (A) It is a figure which shows the time change of the motor rotational speed after carrying out an active short state of a power converter.

  (B) It is a figure which shows the time change of the motor torque after carrying out an active short state of a power converter.

(C) It is a figure which shows the time change of the q-axis current and d-axis current after making an electric power converter into an active short-circuit state.
It is a figure which shows the result of having simulated the operation | movement at the time of hold | maintaining a power converter to an all-off state when stopping rotation of a three-phase alternating current motor.

  (A) It is a figure which shows the time change of the motor rotational speed after making an electric power converter an all-off state.

  (B) It is a figure which shows the time change of the motor torque after making an electric power converter into an all-off state.

(C) It is a figure which shows the time change of the q-axis current and d-axis current after making an all-off state of a power converter.
It is a block diagram which shows the structure of the motor control apparatus which concerns on 2nd Embodiment to which this invention is applied. It is a figure for demonstrating the state of the power converter with respect to the drive control signal f_BRK input into a drive stop switching part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 3 phase alternating current motor 2 Current sensor 3 3 phase / dq conversion part 4 Rotation angle sensor 5 Phase / speed calculation part 6 Current control part 7 Torque control part 8 Non-interference control part 9 Adder 10 dq / 3 phase conversion part 11 PWM Generation unit 12 Power converter 13 Power supply 14 Drive stop switching unit 15 Voltage sensor 21 Smoothing capacitor 22 Upper switching element unit 23 Lower switching element unit

Claims (6)

Motor control for driving an upper switching element group connected to a positive terminal of a power supply to be supplied to an AC motor and a lower switching element group connected to a negative terminal of the power supply to apply an AC voltage to the AC motor In the device
Input means for inputting a rotational speed signal indicating the rotational speed of the AC motor;
When stopping the driving of the AC motor, if the rotational speed of the AC motor input by the input means is equal to or higher than the first rotational speed, either the upper switching element group or the lower switching element group When all of one switching element group is turned on and all of the other switching element group is turned off, and the rotational speed of the AC motor input by the input means is equal to or lower than a second rotational speed, A motor control apparatus comprising: an upper switching element group; and a control unit that shuts off all the switching element groups of the lower switching element group. The control means sets all of the switching elements in either the upper switching element group or the lower switching element group in a conducting state and shuts off all the other switching element groups, and then turns on the AC motor. The switching device group of the said upper side switching element group and the said lower side switching element group will be made into a cutoff state when the rotational speed of this becomes below 3rd rotational speed. Motor control device. When the rotational speed of the AC motor is equal to or higher than a fourth rotational speed after all the switching element groups of the upper switching element group and the lower switching element group are cut off, 2. The motor according to claim 1, wherein all of the switching elements of either the upper switching element group or the lower switching element group are turned on and all of the other switching element groups are turned off. Control device. The first rotation speed is set to be equal to or lower than a rotation speed at which an induced voltage due to a magnetic flux of the AC motor generates a voltage equal to a maximum voltage that can be output by the upper switching element group and the lower switching element group,
The second rotation speed is the state in which all of the switching elements of either the upper switching element group or the lower switching element group are in a conductive state and all of the other switching element groups are in a cut-off state. The motor control device according to claim 1, wherein the magnitude of the brake torque of the AC motor is set to be equal to or higher than a rotational speed exceeding an allowable value. 5. The motor control device according to claim 3, wherein the third rotation speed and the fourth rotation speed are equal to or lower than the first rotation speed and equal to or higher than the second rotation speed. 6. An upper switching element group connected to a positive terminal of a power supply that is mounted on a vehicle and that supplies an AC motor that generates a driving force of the vehicle by generated torque, and a lower switching element group connected to a negative terminal of the power supply In a motor control device that applies an AC voltage to the AC motor,
Input means for inputting a signal for determining whether or not the vehicle is stopped;
When it is determined that the vehicle is in a stopped state based on a signal input by the input means, all of the switching elements in either the upper switching element group or the lower switching element group are made conductive. And a control means for shutting off all of the other switching element group.

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