JP6950409B2 - Drive device - Google Patents

Description

The present invention relates to a drive device, and more particularly to a drive device including a motor and an inverter.

Conventionally, as a drive device of this type, in a drive device including an electric motor and a power conversion device having an inverter circuit for driving the electric motor by switching a plurality of switching elements, the number of pulses of one electric cycle of the electric motor and the electric motor It has been proposed to generate pulse signals of a plurality of switching elements based on the voltage modulation factor and the voltage phase based on the torque command of the above to switch the plurality of switching elements (see, for example, Patent Document 1). .. In this drive device, the total power loss is reduced by generating a pulse signal so as to minimize the total power loss of the power converter and the electric motor based on the number of pulses, the modulation factor, and the voltage phase.

Japanese Unexamined Patent Publication No. 2013-162660

In such a drive device, the current supplied to the motor is rippled with the switching of the plurality of switching elements of the inverter, and the torque ripple of the motor is generated. When the frequency of the torque ripple of the motor is within the resonance region of the motor or the like, the vibration or noise of the motor generated by the torque ripple of the motor may be amplified.

The main object of the drive device of the present invention is to suppress the vibration and noise of the motor from being amplified by the torque ripple of the motor caused by the switching of a plurality of switching elements of the inverter.

The drive device of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The drive device of the present invention
With the motor
An inverter that drives the motor by switching a plurality of switching elements,
A PWM signal of the plurality of switching elements is generated based on the voltage modulation rate and voltage phase based on the torque command of the motor and the number of pulses per unit period of the electric angle of the motor, and the plurality of switching elements are generated. And the control device that switches
It is a drive device equipped with
The control device sets the number of pulses so that the frequency of the torque ripple of the motor generated by switching of the plurality of switching elements is outside the predetermined resonance region.
The gist is that.

In the drive device of the present invention, the number of pulses is set so that the frequency of torque ripple of the motor generated by switching of a plurality of switching elements is outside the predetermined resonance region. As a result, it is possible to suppress the amplification of the vibration and noise of the motor generated by the torque ripple of the motor. Here, examples of the "predetermined resonance region" include a region in which the torsional resonance of the stator of the motor occurs and a region in which the so-called annular zero-order resonance, which is the resonance of the radial expansion and contraction of the stator of the motor, occurs. .. "Frequency of torque ripple" means the frequency of the order of the main component of torque ripple.

In such a drive device of the present invention, the control device sets an efficiency pulse number at which the efficiency of the drive device is optimized, and an efficiency ripple which is a frequency of the torque ripple when the efficiency pulse number is set to the pulse number. When the frequency is outside the predetermined resonance region, the efficiency pulse number is set to the pulse number, and when the efficiency ripple frequency is within the predetermined resonance region, the torque ripple frequency is outside the predetermined resonance region. The number of resonance avoidance pulses that minimizes the decrease in efficiency of the drive device with respect to the case where the efficiency pulse number is set to the pulse number may be set and set to the resonance avoidance pulse number. In this way, in the former case, the efficiency of the drive device can be optimized, and in the latter case, the efficiency of the drive device can be improved to some extent, and the motor generated by the torque ripple of the motor can be used. It is possible to suppress the amplification of vibration and noise.

In the drive device of the present invention in which the number of resonance avoidance pulses is set to the number of pulses when the efficiency ripple frequency is within the predetermined resonance region, the control device is used when the efficiency ripple frequency is within the predetermined resonance region. On the side smaller than the number of efficiency pulses, the frequency of the torque ripple is outside the predetermined resonance region, and the decrease in efficiency of the drive device with respect to the case where the number of efficiency pulses is set to the number of pulses is minimized. The number of avoidance pulses may be set. In this way, an increase in inverter loss (switching loss) can be further suppressed.

Further, in the drive device of the present invention in which the number of resonance avoidance pulses is set to the number of pulses when the efficiency ripple frequency is within a predetermined resonance region, the control device is described when the rotation speed of the motor is equal to or less than a threshold value. The resonance avoidance pulse number may be set to the pulse number, and when the rotation number of the motor is larger than the threshold rotation number, the efficiency pulse number may be set to the pulse number. In this way, when the rotation speed of the motor is low, the vibration and noise of the motor generated by the torque ripple of the motor are suppressed, and when the rotation speed of the motor is high, the efficiency of the drive device is optimized. be able to.

In the drive device of the present invention, the control device of the motor has a map in which the relationship between the rotation speed and torque command of the motor and the pulse number is predetermined so that the frequency of the torque ripple is outside the predetermined resonance region. The number of revolutions and the torque command may be applied to set the number of pulses. Further, the control device applies the rotation speed of the motor to a map in which the relationship between the rotation speed of the motor and the pulse number is predetermined so that the frequency of the torque ripple is outside the predetermined resonance region, and the pulse is applied. The number may be set. In these cases, the number of pulses can be set using the map.

It is a block diagram which shows the outline of the structure of the electric vehicle 20 which mounts the drive device as one Example of this invention. It is a flowchart which shows an example of the pulse number setting routine executed by an electronic control unit 50. It is explanatory drawing which shows an example of the relationship between the rotation speed Nm of a motor 32 and an efficiency ripple frequency fefri. It is explanatory drawing which shows an example of the relationship between the rotation speed Nm of a motor 32, and a ripple frequency. It is explanatory drawing which shows an example of the relationship between the rotation speed Nm of the motor 32 of a modification, and the ripple frequency. It is explanatory drawing which shows an example of the pulse number setting routine of the modification. It is explanatory drawing which shows an example of the relationship between the rotation speed Nm of the motor 32 of a modification, and the ripple frequency. It is explanatory drawing which shows an example of the pulse number setting routine of the modification.

Next, a mode for carrying out the present invention will be described with reference to examples.

FIG. 1 is a configuration diagram showing an outline of a configuration of an electric vehicle 20 equipped with a drive device as an embodiment of the present invention. As shown in the figure, the electric vehicle 20 of the embodiment includes a motor 32, an inverter 34, a battery 36 as a power storage device, and an electronic control unit 50. As the "driving device" of the embodiment, the motor 32, the inverter 34, and the electronic control unit 50 correspond to each other.

The motor 32 is configured as a synchronous generator motor, and includes a rotor in which a permanent magnet is embedded and a stator in which a three-phase coil is wound. The motor 32 is connected to a drive shaft 26 in which a rotor is connected to drive wheels 22a and 22b via a differential gear 24.

The inverter 34 is used to drive the motor 32 and is connected to the battery 36 via the power line 38. The inverter 34 has transistors T11 to T16 as six switching elements, and six diodes D11 to D16 connected in parallel to each of the six transistors T11 to T16. Two transistors T11 to T16 are arranged in pairs so as to be on the source side and the sink side with respect to the positive electrode side line and the negative electrode side line of the power line 38, respectively. Further, each of the three-phase coils (U-phase, V-phase, and W-phase coils) of the motor 32 is connected to each of the connection points between the transistors paired with the transistors T11 to T16. Therefore, when a voltage is applied to the inverter 34, the electronic control unit 50 adjusts the ratio of the on-time of the paired transistors T11 to T16, so that a rotating magnetic field is formed in the three-phase coil and the motor. 32 is rotationally driven.

The battery 36 is configured as, for example, a lithium ion secondary battery or a nickel hydrogen secondary battery, and is connected to the inverter 34 via the power line 38 as described above. A capacitor 39 is attached to the positive electrode side line and the negative electrode side line of the power line 38.

The electronic control unit 50 is configured as a microprocessor centered on a CPU 52, and includes a ROM 54 for storing a processing program, a RAM 56 for temporarily storing data, and an input / output port in addition to the CPU 52. Signals from various sensors are input to the electronic control unit 50 via input ports. As the signal input to the electronic control unit 50, for example, the rotation position θm from the rotation position detection sensor (for example, resolver) 32a that detects the rotation position of the rotor of the motor 32, and the phase current of each phase of the motor 32 are used. The phase currents Iu and Iv from the current sensors 32u and 32v to be detected can be mentioned. Further, the voltage Vb of the battery 36 from a voltage sensor (not shown) attached between the terminals of the battery 36, the current Ib of the battery 36 from the current sensor (not shown) attached to the output terminal of the battery 36, and the terminals of the capacitor 39. The voltage VH of the capacitor 39 (power line 38) from the voltage sensor 39a attached to the above can also be mentioned. Further, the ignition signal from the ignition switch 60 and the shift position SP from the shift position sensor 62 that detects the operation position of the shift lever 61 can also be mentioned. In addition, from the accelerator opening Acc from the accelerator pedal position sensor 64 that detects the amount of depression of the accelerator pedal 63, the brake pedal position BP from the brake pedal position sensor 66 that detects the amount of depression of the brake pedal 65, and the vehicle speed sensor 68. Vehicle speed V can also be mentioned. From the electronic control unit 50, a switching control signal or the like to the transistors T11 to T16 of the inverter 34 is output via the output port. The electronic control unit 50 calculates the electric angle θe and the rotation speed Nm of the motor 32 based on the rotation position θm of the rotor of the motor 32 from the rotation position detection sensor 32a.

In the electric vehicle 20 of the embodiment configured in this way, the electronic control unit 50 sets the required torque Td * of the drive shaft 26 based on the accelerator opening degree Acc and the vehicle speed V by a control routine (not shown), and sets the required torque Td *. The torque Td * is set to the torque command Tm * of the motor 32. Then, the switching control of the transistors T11 to T16 of the inverter 34 is performed so that the motor 32 is driven by the torque command Tm *.

Here, the control of the inverter 34 will be described. The electronic control unit 50 transmits the PWM signals of the transistors T11 to T16 based on the voltage modulation factor Rm, the voltage phase θp, and the number of pulses Np per unit period (in the embodiment, one period of the electric angle θe of the motor 32). It is generated and the transistors T11 to T16 are switched.

Specifically, it is as follows. First, the electronic control unit 50 uses the electric angle θe of the motor 32 to U, assuming that the sum of the phase currents Iu, Iv, and Iw of each phase (U phase, V phase, W phase) of the motor 32 is 0. Coordinate conversion (3-phase-2 phase conversion) is performed on the phase and V phase currents Iu and Iv to the d-axis and q-axis currents Id and Iq. Subsequently, the d-axis and q-axis current commands Id * and Iq * are set based on the torque command Tm * of the motor 32, and the d-axis and q-axis current commands Id * and Iq * and the currents Id and Iq are used. Set the d-axis and q-axis voltage commands Vd * and Vq *. Then, the voltage modulation factor Rm and the voltage phase θp are set using the set d-axis and q-axis voltage commands Vd * and Vq *. Here, the modulation factor Rm is the voltage command absolute value Vdq calculated as the square root of the sum of the square of the voltage command Vd * on the d-axis and the square of the voltage command Vq * on the q-axis of the capacitor 39 (power line 38). It can be obtained by dividing by the voltage VH of. The voltage phase θp can be obtained as an angle with respect to the q-axis of a vector having voltage commands Vd * and Vq * on the d-axis and q-axis as components. Next, the pulse number Np is set by the pulse number setting routine described later, a PWM signal of the transistors T11 to T16 is generated based on the voltage modulation factor Rm, the voltage phase θp, and the pulse number Np, and the transistors T11 to T16 are generated. Switching of transistors T11 to T16 is performed using the PWM signal of.

In the embodiment, the PWM signals of the transistors T11 to T16 are generated so that the harmonic component of the desired order is reduced and the total loss Lsum of the loss of the motor 32 and the loss of the inverter 34 is reduced. Hereinafter, a method of generating a PWM signal of the transistors T11 to T16 will be described. In the description of this generation method, the reference numerals for the motor 32, the inverter 34, and the transistors T11 to T16 are omitted.

When the angular speed of the rotor of the motor is "ω" and the time is "t", the PWM signal is generated so as to have half-wave symmetry represented by "f (ωt) = -f (ωt + π)". When the constraint condition is used, the PWM signal f (θe) when the electric angle of the motor is “θe” can be expressed by the equation (1) by using the Fourier series expansion. By using this constraint condition, it is possible to eliminate even-order harmonic components and simplify control. In equation (1), "n" is the order of the harmonic components, 1, 3, 5, 7, ... (Odd integer), and "M" is the transistor per half cycle of the electric angle θe of the motor. The number of switching times (excluding switching at the reference electric angle (for example, 0 °, 180 °, etc.)). The number of switching times M is "M = Np-1" when the number of pulses per cycle of the electric angle θe of the motor is "Np". Further, in the equation (1), "θe, m" is the m-th switching electric angle of the transistor, "an" is the Fourier cosine coefficient, "bn" is the Fourier sine coefficient, and "a0" is the direct current. It is an ingredient. From the Fourier cosine coefficient an and the Fourier sine coefficient bn of the equation (1), the amplitude Cn of the harmonic component of each order and the phase αn of the harmonic component of each order can be expressed by the equation (2).

It should be noted that the constraint condition that the PWM signal is generated so as to have not only half-wave symmetry but also odd symmetry represented by "f (ωt) = f (π-ωt)" may be used. By using this constraint condition, the cosine wave component of the harmonic can be eliminated. In this case, "n" is 1,5,7,11, ... (an odd integer excluding multiples of 3), and "M" is the transistor per quarter period of the electric angle θe of the motor. The number of switchings (excluding switching at the reference electric angle) becomes "M = (Np-1) / 2".

In the embodiment, as a method of generating the PWM signal, a method of reducing the sum of the harmonic components of each order is considered. Of the motor losses, the iron loss Wi can be expressed by equation (3) from Steinmetz's empirical formula. Here, in the equation (3), "Wh" is the hysteresis loss, "We" is the eddy current loss, "Kh" is the hysteresis loss coefficient, "Bm" is the magnetic flux density, and "fm". Is the rotational magnetic flux frequency of the motor, and "Ke" is the eddy current loss coefficient.

Focusing on the eddy current loss We, which has a large proportion of the total iron loss of the motor, and assuming that the phase potential of the motor is "Vm", generally, the value obtained by dividing the magnetic flux density Bm and the phase potential Vm of the motor by the rotational magnetic flux frequency fm (Vm). Since / fm) has a proportional relationship, the equation (4) can be derived. Then, in the equation (4), the hysteresis loss coefficient Ke (constant) is ignored, the rotational magnetic flux frequency fm of the order n is replaced with the order n, the phase potential of the motor of the order n is set to "Vmn", and the loss is reduced. Assuming that the maximum order to be considered is "N" (for example, 107th order), the sum of the harmonic components of each order can be expressed by the equation (5). In order to reduce the loss of the motor, the value of this equation (5) may be reduced. Since the motor phase potential Vmn of the order n means the amplitude Cn of the harmonic component of the order n, the value of the equation (6) may be reduced.

If the PWM signal f (θe) of the equation (1) is set so that the value of the equation (6) is reduced, the sum of the harmonic components of each order is reduced, and the loss of the motor is reduced. Preferably, the PWM signal f (θe) of the equation (1) is set so that the value of the equation (6) is minimized. In the embodiment, in the equation (1), a value of 0 is set for "a1" in order to set the one-dimensional fundamental wave phase to 0 °. In this way, the PWM signal of each transistor of the inverter can be generated.

Next, the operation of the electric vehicle 20 of the embodiment configured in this way, particularly the operation when setting the pulse number Np will be described. FIG. 2 is a flowchart showing an example of a pulse number setting routine executed by the electronic control unit 50. This routine is executed repeatedly.

When the pulse number setting routine of FIG. 2 is executed, the CPU 52 of the electronic control unit 50 first inputs the rotation speed Nm of the motor 32 and the torque command Tm * (step S100). Here, the rotation number Nm of the motor 32 is input calculated based on the rotation position θm of the rotor of the motor 32 from the rotation position detection sensor 32a. For the torque command Tm * of the motor 32, a value set by the above-mentioned control routine is input.

Subsequently, based on the input rotation speed Nm of the motor 32 and the torque command Tm *, the efficiency pulse number Npef at which the efficiency of the drive device becomes good (preferably optimal) is set (step S110). Here, in the embodiment, the efficiency pulse number Npef is stored in the ROM 54 as an efficiency pulse number setting map by predetermining the relationship between the rotation number Nm of the motor 32 and the torque command Tm * and the efficiency pulse number Npef. When the rotation number Nm of the motor 32 and the torque command Tm * are given, the corresponding efficiency pulse number Npef is derived and set from this map.

When the efficiency pulse number Npef is set in this way, when the efficiency pulse number Npef is set to the pulse number Np based on the set efficiency pulse number Npef and the rotation number Nm of the motor 32 (using this pulse number Np, the inverter 34 The frequency of the main component of the torque ripple of the motor 32 generated by the switching of the transistors T11 to T16 of the inverter 34 of the inverter 34 (when the PWM signal of the pulses T11 to T16 is generated to switch the transistors T11 to T16) is estimated (the frequency of the main component of the torque ripple of the motor 32 is estimated. Step S120). When the transistors T11 to T16 of the inverter 34 are switched, the current supplied to the motor 32 is rippled along with the switching, and the torque ripple of the motor 32 is generated. The order of the main components of the torque ripple (hereinafter referred to as "ripple order") depends on the pulse number Np, and the frequency of the ripple order (hereinafter referred to as "ripple frequency") depends on the rotation speed Nm of the motor 32. do. Hereinafter, the ripple frequency when the efficiency pulse number Npef is set to the pulse number Np is referred to as "efficiency ripple frequency fefri".

In the embodiment, the efficiency ripple frequency fefri is stored in the ROM 54 as an efficiency ripple frequency estimation map by predetermining the relationship between the efficiency pulse number Npef and the rotation speed Nm of the motor 32 and the efficiency ripple frequency fefri, and the efficiency pulse number. Given the Npef and the rotation speed Nm of the motor 32, the corresponding efficiency ripple frequency fefri was derived from this map and estimated.

FIG. 3 is an explanatory diagram showing an example of the relationship between the rotation speed Nm of the motor 32 and the efficiency ripple frequency fefri. In the figure, the thick solid line shows this relationship. Further, in FIG. 3, for reference, the relationship between the rotation speed Nm of the motor 32 and the frequency of each order of the torque ripple of the motor 32 generated by the switching of the transistors T11 to T16 of the inverter 34 is shown in a fine solid line. Was also shown. In the figure, "6th order (Np1)" to "54th order (Np9)" indicate the relationship between the pulse number Np and the ripple order (order of the main component of torque ripple), and specifically, , It is shown that the ripple order when the value Np1 to the value Np9 is set to the pulse number Np is electric 6th order to electric 54th order. In FIG. 3, the efficiency pulse number Npef is a value Np8 in the region where the rotation number Nm of the motor 32 is equal to or less than the threshold Nm1, and is a value Np6 in the region where the rotation number Nm of the motor 32 is larger than the threshold Nm1 and is less than the threshold Nm2. The relationship between the rotation speed Nm of the motor 32 and the efficiency ripple frequency fefri when the rotation speed Nm of the motor 32 is larger than the threshold value Nm2 and the value is Np3 is shown.

When the efficiency ripple frequency fefri is estimated in this way, it is determined whether or not the estimated efficiency ripple frequency fefri is outside the torsional resonance region and the ring 0th-order resonance region (step S130). Here, the "twisting resonance region" is a region where the torsional resonance of the stator of the motor 32 occurs (for example, about 900 to 1100 Hz), and the "annular 0th-order resonance region" is the radial direction of the stator of the motor 32. This is a region (for example, about 4000 to 6000 Hz) where the so-called annular zero-order resonance, which is the resonance of expansion and contraction, occurs.

When it is determined in step S130 that the efficiency ripple frequency fefri is outside the twist resonance region and the ring 0th resonance region, the efficiency pulse number Npef is set to the pulse number Np (step S140), and this routine is terminated. In this case, the efficiency of the drive device can be made good (preferably optimal).

When it is determined in step S130 that the efficiency ripple frequency fefri is within the torsional resonance region or the ring 0th-order resonance region, the ripple frequency is outside the torsional resonance region and based on the rotation speed Nm of the motor 32 and the torque command Tm *. The resonance avoidance pulse number Npre is set (step S150) in which the amount of decrease in the efficiency of the drive device is small (preferably the minimum) when the efficiency pulse number Npef is set to the pulse number Np while being outside the annular 0th resonance region. ), Set the resonance avoidance pulse number Npre to the pulse number Np (step S160), and end this routine. Here, in the embodiment, the resonance avoidance pulse number Npre is stored in the ROM 54 as a map for setting the resonance avoidance pulse number by predetermining the relationship between the rotation number Nm of the motor 32 and the torque command Tm * and the resonance avoidance pulse number Npre. When the rotation speed Nm of the motor 32 is given, the corresponding resonance avoidance pulse number Npre is derived from this map and set. By setting the number of pulses Np (number of resonance avoidance pulses Npre) in this way, the efficiency of the drive device is improved to some extent (although it is lower than when the efficiency pulse number Npef is set to the pulse number Np), while being improved to some extent. It is possible to suppress the amplification of vibration and noise of the motor 32 generated by the torque ripple of the motor 32.

FIG. 4 is an explanatory diagram showing an example of the relationship between the rotation speed Nm of the motor 32 and the ripple frequency. In the figure, the thick solid line shows this relationship. Further, in FIG. 4, for reference, the relationship between the rotation speed Nm of the motor 32 and the frequency of each order of the torque ripple of the motor 32 generated by the switching of the transistors T11 to T16 of the inverter 34 is shown in a fine solid line. The relationship between the rotation speed Nm of the motor 32 and the efficiency ripple frequency fefri is shown by the thick dotted line. In the case of FIG. 4, when the rotation speed Nm of the motor 32 is within the rotation speed regions R11 to R13 (the rotation speed region of the motor 32 in which the efficiency ripple frequency fefri is outside the torsional resonance region and the ring 0th resonance region), the efficiency is increased. The number of pulses Npef is set to the number of pulses Np. As a result, the efficiency of the drive device can be made good (preferably optimal). Further, when the rotation speed Nm of the motor 32 is within the rotation speed regions R21 to R24 (the rotation speed region of the motor 32 in which the efficiency ripple frequency fefri is within the torsional resonance region or the ring 0th resonance region), the number of resonance avoidance pulses. Set Npre to the number of pulses Np. Specifically, when the rotation speed Nm of the motor 32 is within the rotation speed regions R21, R22, R24, the pulse number Np (resonance avoidance pulse number Npre) is set on the side smaller than the efficiency pulse number Npf, and the motor 32 When the rotation speed Nm is within the rotation speed region R23, the pulse number Np (resonance avoidance pulse number Npre) is set on the side larger than the efficiency pulse number Npef. As a result, it is possible to suppress the vibration and noise of the motor 32 generated by the torque ripple of the motor 32 from being amplified while improving the efficiency of the drive device to some extent.

In the drive device mounted on the electric vehicle 20 of the above-described embodiment, the efficiency pulse number Npef at which the efficiency of the drive device is good (preferably optimum) is set, and the efficiency pulse number Npef is set to the pulse number Np. When the ripple frequency (efficiency ripple frequency fefri) at the time of setting is outside the twist resonance region and the ring 0th resonance region, the efficiency pulse number Npef is set to the pulse number Np and the transistors T11 to T16 of the inverter 34 are switched. To do. As a result, the efficiency of the drive device can be made good (preferably optimal). On the other hand, when the efficiency ripple frequency fefri is within the torsional resonance region or the ring 0th-order resonance region, the ripple frequency is outside the torsional resonance region and the ring 0th-order resonance region, and the efficiency pulse number Npef is set to the pulse number Np. The resonance avoidance pulse number Npre, in which the amount of decrease in the efficiency of the drive device is small (preferably the minimum) with respect to the setting, is set, and the resonance avoidance pulse number Npre is set to the pulse number Np, and the transistors T11 to T16 of the inverter 34 are set. To switch. As a result, the vibration and noise of the motor 32 generated by the torque ripple of the motor 32 are amplified while improving the efficiency of the drive device to some extent (although it is lower than the case where the efficiency pulse number Npef is set to the pulse number Np). It can be suppressed.

In the drive device mounted on the electric vehicle 20 of the embodiment, when the efficiency ripple frequency fefri is within the torsional resonance region or the annular 0th-order resonance region, the ripple frequency is outside the torsional resonance region and outside the annular 0th-order resonance region. The resonance avoidance pulse number Npre is set, and the resonance avoidance pulse number Npre is set to the number of pulses. It was set to Np. However, on the side smaller than the efficiency pulse number Npef, the ripple frequency is outside the twist resonance region and the ring 0th resonance region, and the amount of decrease in the efficiency of the drive device when the efficiency pulse number Npef is set to the pulse number Np. The resonance avoidance pulse number Npre2 may be set to be small, and the resonance avoidance pulse number Npre2 may be set to the pulse number Np. FIG. 5 shows an example of the relationship between the rotation speed Nm of the motor 32 and the ripple frequency in this case. When the number of pulses Np is increased, the number of switchings of the transistors T11 to T16 is increased, and the loss (switching loss) of the inverter 34 is increased. Therefore, by setting the number of pulses Np in this way, it is possible to suppress an increase in the loss of the inverter 34. Further, on the side larger than the efficiency pulse number Npef, the ripple frequency is outside the twist resonance region and the ring 0th resonance region, and the amount of decrease in the efficiency of the drive device when the efficiency pulse number Npef is set to the pulse number Np. The resonance avoidance pulse number Npre3 may be set to be small, and the resonance avoidance pulse number Npre3 may be set to the pulse number Np.

In the drive device mounted on the electric vehicle 20 of the embodiment, the electronic control unit 50 is assumed to execute the pulse number setting routine of FIG. However, the electronic control unit 50 may execute the pulse number setting routine shown in FIG. The pulse number setting routine of FIG. 6 is the same as the pulse number setting routine of FIG. 2 except that the process of step S135 is added. Therefore, the same process is assigned the same step number, and detailed description thereof will be omitted. In the pulse number setting routine of FIG. 6, the CPU 52 of the electronic control unit 50 sets the rotation speed Nm of the motor 32 to the threshold Nmref when the efficiency ripple frequency fefri is within the twist resonance region or the annulus 0th resonance region in step S130. (Step S135). Then, when the rotation speed Nm of the motor 32 is equal to or less than the threshold value Nmref, the resonance avoidance pulse number Npre is set and the resonance avoidance pulse number Npre is set to the pulse number Np (steps S150 and S160), and this routine is terminated. .. On the other hand, when the rotation speed Nm of the motor 32 is larger than the threshold value Nmref, the pulse number Npef is set to the pulse number Np (step S140), and this routine is terminated. FIG. 7 shows an example of the relationship between the rotation speed Nm of the motor 32 and the ripple frequency in this case. When the rotation speed Nm of the motor 32 is small (vehicle speed V is low), the driver can easily feel the vibration and noise of the motor 32 due to reasons such as low background noise such as road noise, and the rotation speed Nm of the motor 32 is large. When (the vehicle speed V is high), it is considered that the driver is unlikely to feel the vibration or noise of the motor 32 due to a large background noise or the like. Therefore, by setting the pulse number Np in this way, when the rotation speed Nm of the motor 32 is small, the vibration and noise of the motor 32 generated by the torque ripple of the motor 32 are suppressed, and the rotation of the motor 32 is suppressed. When the number Nm is large, the efficiency of the drive device can be made good (preferably optimal).

In the drive device mounted on the electric vehicle 20 of the embodiment, the efficiency pulse number Npef is set based on the rotation speed Nm of the motor 32 and the torque command Tm *, and the efficiency ripple frequency fefri is within the torsional resonance region or the ring 0th order. When it is within the resonance region, the resonance avoidance pulse number Npre is set based on the rotation speed Nm of the motor 32 and the torque command Tm *. However, when the efficiency pulse number Npef is set based only on the rotation speed Nm of the motor 32 and the efficiency ripple frequency fefri is in the torsional resonance region or the ring 0th resonance region, it is based only on the rotation speed Nm of the motor 32. The resonance avoidance pulse number Npre may be set. In this case, the efficiency pulse number Npef is given the rotation number Nm of the motor 32 by predetermining the relationship between the rotation number Nm of the motor 32 and the efficiency pulse number Npef and storing it in the ROM 54 as a map for setting the efficiency pulse number. And, the corresponding efficiency pulse number Npef may be derived from this map and set. Further, the resonance avoidance pulse number Npre is stored in the ROM 54 as a map for setting the resonance avoidance pulse number by predetermining the relationship between the rotation number Nm of the motor 32 and the resonance avoidance pulse number Npre, and the rotation number Nm of the motor 32 is calculated. Given, the corresponding resonance avoidance pulse number Npre may be derived and set from this map.

In the drive device mounted on the electric vehicle 20 of the embodiment, the electronic control unit 50 is assumed to execute the pulse number setting routine of FIG. However, the electronic control unit 50 may execute the pulse number setting routine shown in FIG. In the pulse number setting routine of FIG. 8, the CPU 52 of the electronic control unit 50 inputs the rotation speed Nm of the motor 32 and the torque command Tm * (step S200), and inputs the rotation speed Nm of the motor 32 and the torque command Tm *. The pulse number Np is set using the pulse number setting map (step S210), and this routine is terminated. Here, in the pulse number setting map, the relationship between the rotation speed Nm of the motor 32 and the torque command Tm * and the pulse number Np is predetermined so that the ripple frequency is outside the torsional resonance region and outside the 0th-order annular resonance region. The map is defined so that the relationship between the rotation speed Nm of the motor 32 and the ripple frequency is the same as the thick solid line in FIG. 4 for each value of the torque command Tm *. Specifically, in the pulse number setting map, the rotation number Nm of the motor 32 is a rotation number region in which the efficiency ripple frequency fefri is outside the twist resonance region and the ring 0th resonance region (in the case of FIG. 4, the rotation number). Within the regions R11 to R13), the efficiency pulse number Npef is set as the pulse number Np, and the rotation speed Nm of the motor 32 is the rotation speed at which the efficiency ripple frequency fefri is within the twist resonance region or the annular 0th order resonance region. When it is in the region (in the case of FIG. 4, the rotation frequency regions R21 to R24), the resonance avoidance pulse number Npre is set as the pulse number Np. Even in this case, the same effect as in the embodiment can be obtained. As the pulse number setting map, the relationship between the rotation number Nm of the motor 32 and the pulse number Np is used instead of the map that defines the relationship between the rotation number Nm of the motor 32 and the torque command Tm * and the pulse number Np. A defined map may be used.

In the drive device mounted on the electric vehicle 20 of the embodiment, a torsional resonance region and a ring 0th-order resonance region are used as resonance regions. However, as the resonance region, only one of the torsional resonance region and the 0th-order annular resonance region may be used, or one or both of the torsional resonance region and the 0th-order annular resonance region may be used. Alternatively, or in addition to both the torsional resonance region and the 0th-order annular resonance region, the resonance region of the entire drive device, the resonance region of the entire electric vehicle 20, and the like may be used.

In the embodiment, the drive device is mounted on the electric vehicle 20 including the motor 32. However, it may be in the form of a drive device mounted on a hybrid vehicle including an engine in addition to the motor 32, or may be in the form of a drive device mounted on a moving body such as a vehicle, a ship, or an aircraft other than the automobile. It may be in the form of a drive device mounted on non-moving equipment such as construction equipment.

The correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem will be described. In the embodiment, the motor 32 corresponds to the "motor", the inverter 34 corresponds to the "inverter", and the electronic control unit 50 corresponds to the "control device".

Regarding the correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem, the invention described in the column of means for solving the problem in the examples is carried out. Since it is an example for specifically explaining the form for solving the problem, the elements of the invention described in the column of means for solving the problem are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be performed based on the description in the column, and the examples are the inventions described in the column of means for solving the problem. It is just a concrete example.

Although the embodiments for carrying out the present invention have been described above with reference to examples, the present invention is not limited to these examples, and various embodiments are used without departing from the gist of the present invention. Of course, it can be done.

The present invention can be used in the driving device manufacturing industry and the like.

20 electric vehicle, 22a, 22b drive wheel, 24 differential gear, 26 drive shaft, 32 motor, 32a rotation position detection sensor, 32u, 32v current sensor, 34 inverter, 36 battery, 38 power line, 39 condenser, 39a voltage sensor, 50 Electronic control unit, 52 CPU, 54 ROM, 56 RAM, 60 Ignition switch, 61 Shift lever, 62 Shift position sensor, 63 Accelerator pedal, 64 Accelerator pedal position sensor, 65 Brake pedal, 66 Brake pedal position sensor, 68 Vehicle speed sensor , D11 to D16 diodes, T11 to T16 transistors.

Claims (1)

With the motor
An inverter that drives the motor by switching a plurality of switching elements,
A PWM signal of the plurality of switching elements is generated based on the voltage modulation rate and voltage phase based on the torque command of the motor and the number of pulses per unit period of the electric angle of the motor, and the plurality of switching elements are generated. And the control device that switches
It is a drive device equipped with
The control device is
Set the number of efficiency pulses that optimizes the efficiency of the drive,
When the efficiency ripple frequency, which is the frequency of the torque ripple of the motor generated by switching of the plurality of switching elements when the efficiency pulse number is set to the pulse number, is outside the predetermined resonance region, the efficiency pulse number To the number of pulses
When the efficiency ripple frequency is within the predetermined resonance region, the frequency of the torque ripple is outside the predetermined resonance region and the decrease in efficiency of the drive device is minimized with respect to the case where the efficiency pulse number is set to the pulse number. The number of resonance avoidance pulses is set to the number of pulses.
Drive device.

Images