JP2005229676A - Two-phase modulation motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-phase modulation motor controller capable of realizing the good reduction of switching loss of an inverter. <P>SOLUTION: A two-phase modulation system switching judging means 87 of a two-phase modulation voltage command generating means 84 commands 2π/3 fixed system two-phase modulation capable of performing two-phase modulation surely in a region of torque and r.p.m. corresponding to those in a region where a phase voltage has a substantially small amplitude by substituting for a map prestoring input torque command trq* and motor r.p.m. Nmot, and employs π/3 fixed system having lower switching loss in other regions. Consequently, stabilized high efficiency motor drive is ensured over the entire operating region. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a two-phase modulation motor control device.

The demand for reducing losses is increasing in various fields against the background of environmental problems in recent years, and PMW inverters (hereinafter referred to as inverters) that operate three-phase AC motors are no exception.
The PWM control of a general three-phase AC motor is three-phase modulation. However, by utilizing the fact that the motor current is determined not by the phase voltage but by the inter-phase voltage, each phase voltage is set at predetermined intervals while securing the inter-phase voltage. 1987 is a two-phase modulation that can reduce the switching loss of the inverter by constantly turning on the switching element of the inverter and sequentially fixing the electrical angle π / 3 (60 degrees) to the high power level or the low power level for each phase. The explanation is given in pages 110, 111, 125, etc. of the book “Semiconductor Power Conversion Circuit” published by the Institute of Electrical Engineers of Japan in March, 2000. Hereinafter, the two-phase modulation method is referred to as a π / 3 fixed method or a fixed phase 60 degree switching method.

In addition, when the phase voltage is small when the phase voltage is small by sequentially fixing the electrical power 2π / 3 (120 degrees) to the high power level or low power level for each phase to reduce the switching loss of the inverter. The following Patent Document 1 proposes to stop and apply a three-phase voltage to the motor. Hereinafter, the two-phase modulation method is referred to as a 2π / 3 fixed method or a fixed phase 120 degree switching method.
Japanese Patent No. 2577738

  A traveling motor such as an electric vehicle or a hybrid vehicle needs to be operated in each of the four quadrants of the motor output two-dimensional coordinate space having torque and rotation speed as dimensional parameters, respectively. There is a problem that the loss is not sufficiently reduced, for example, in a high-speed, large-torque region.

  On the other hand, the stationary phase 60 degree switching method can synchronize the stationary period of the stationary phase and the vicinity of the positive and negative peaks of the phase current of the stationary phase, and has an advantage of a large switching loss reduction effect than the stationary phase 120 degree switching method. When the output voltage amplitude is small, there has been a problem that a good two-phase modulation operation becomes unsuccessful due to a wrong fixed phase switching timing.

  In addition, in the switching between the three-phase modulation driving and the 2π / 3-fixed two-phase modulation driving described above, the switching based on the amplitude determination of the three-phase voltage is an alternating current waveform in which the three-phase voltage fluctuates over time. As a result, the switching accuracy is reduced, and an appropriate loss reduction effect cannot be obtained.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a two-phase modulation method capable of satisfactorily reducing the switching loss of an inverter while suppressing a malfunction of switching a fixed phase.

  The two-phase modulation motor control system of the first invention is a two-phase modulation system in which each phase voltage of the three-phase voltage applied to the three-phase AC motor is fixed in order for each predetermined period, and the amplitude of the phase voltage is a predetermined threshold value. When the value is less than the value, the two-phase modulation method is interrupted and the three-phase voltage is output, and when the amplitude of the phase voltage is equal to or greater than a predetermined threshold, each phase voltage is fixed in order every π / 3 period. The π / 3 fixing method is employed.

  According to the present invention, when the amplitude of the three-phase voltage is large, the π / 3 fixing method is adopted instead of the conventional 2π / 3 fixing method, so that the switching loss of the inverter, particularly the switching of the inverter in the high torque power running high speed rotation region. By improving the loss reduction effect, the efficiency can be improved.

  The two-phase modulation motor control system of the second invention is a two-phase modulation system in which each phase voltage of the three-phase voltage applied to the three-phase AC motor is fixed in order every predetermined period, and the q-axis current of the three-phase AC motor When the coordinate point defined by iq and d-axis current id is within a predetermined region including the origin on the two-dimensional plane of the current determined by q-axis current iq and d-axis current id, the two-phase modulation method is The three-phase voltage is output after interruption, and two-phase modulation is employed when the coordinate point is outside the predetermined region.

  That is, in this two-phase modulation method, switching between the three-phase modulation and the two-phase modulation is performed using the amplitude of the phase voltage used in the first invention as a threshold value, instead of the q-axis current iq and the d-axis current id. When the absolute values of these are small (more precisely, the region where the amplitude of the three-phase voltage defined by the q-axis current iq and the d-axis current id is small), the three-phase voltages are output. Shifts to the two-phase modulation method when the absolute value of is large (more precisely, the region where the amplitude of the three-phase voltage defined by the q-axis current iq and the d-axis current id is large). The two-phase modulation method at this time may be a 2π / 3 fixed method or a π / 3 fixed method.

  In this way, the switching can be performed easily and accurately. More specifically, the amplitude of the phase voltage changes from moment to moment for each phase, and there is also an influence of a noise voltage superimposed on the phase voltage, which causes a problem of deterioration in determination accuracy. On the other hand, the q-axis current iq and the d-axis current id are substantially less compared with the amplitude of the phase voltage, and the fluctuation can be detected easily and stably, so that the accuracy in the switching is improved. That is why.

  A two-phase modulation motor control system according to a third aspect of the present invention is a two-phase modulation system in which each phase voltage of a three-phase voltage applied to a three-phase AC motor is fixed in order at predetermined intervals, and the torque and rotation of the three-phase AC motor. When the coordinate point determined by the number is within a predetermined region including the origin on the two-dimensional plane of the motor output determined by the torque and the number of rotations, the two-phase modulation method is interrupted and the three-phase voltage is output. However, when the coordinate point is outside the predetermined area, two-phase modulation is employed.

  That is, in this two-phase modulation system, instead of performing switching between three-phase modulation and two-phase modulation using the phase voltage amplitude used in the first invention as a threshold value, a map of torque and rotational speed (that is, A function that uses torque and rotation speed as variables, and outputs a three-phase voltage when their absolute values are small (exactly, the three-phase voltage amplitude defined by torque and rotation speed is small). When the absolute values thereof are large (more precisely, the region where the amplitude of the three-phase voltage defined by the torque and the rotational speed is large), the mode shifts to the two-phase modulation method. In this way, in addition to being able to perform the switching easily and accurately, the π / 3 fixed method that has a large effect of reducing the switching loss can be utilized to the maximum extent. More specifically, the amplitude of the phase voltage changes from moment to moment for each phase, and there is also an influence of a noise voltage superimposed on the phase voltage, which causes a problem of deterioration in determination accuracy. On the other hand, the torque and the rotational speed are essentially less changed than the amplitude of the phase voltage, and the fluctuation can be detected easily and stably, so that the accuracy in the switching is improved and π / 3 is fixed. The controllable range of the system can be expanded appropriately.

  In aspect 1 of the second or third aspect of the invention, π / 3-fixed two-phase modulation is employed in which each phase voltage is fixed in turn every π / 3 period when the coordinate point is outside the predetermined region. In this way, since the π / 3 fixed method is adopted instead of the 2π / 3 fixed method, the switching loss of the inverter can be further reduced as in the first invention.

  In aspect 2 which is a preferred aspect of the third invention, the two-dimensional plane of the motor output is constituted by a forward rotational force quadrant, a forward rotational regeneration quadrant, a reverse rotational force quadrant, and a reverse rotational regeneration quadrant, When the directions are equal, the threshold value (absolute value) for torque is set to be larger in the regenerative quadrant than the power quadrant, so that the phase voltage amplitude is substantially reduced in spite of the use of the torque and the rotational speed. Three-phase modulation drive can be performed when equal to or less than a predetermined threshold value.

  In the aspect 3, which is a preferred aspect of the third invention, the shape of the predetermined region is substantially rotationally symmetric in the forward rotational force quadrant and the reverse rotational force quadrant, and therefore in the forward rotational force quadrant and the reverse rotational force quadrant. Three-phase modulation driving can be performed when the amplitude of the phase voltage becomes equal to or less than a predetermined threshold value. In addition, the shape of the predetermined region can perform three-phase modulation driving when the amplitude of the phase voltage is equal to or less than a predetermined threshold value in the forward rotation regeneration quadrant and the reverse rotation regeneration quadrant.

  A two-phase modulation motor control system according to a fourth aspect of the present invention is a two-phase modulation system in which each phase voltage of a three-phase voltage applied to a three-phase AC motor is fixed in order at predetermined intervals, and the amplitude of the phase voltage is a predetermined threshold. When the phase voltage is less than the value, a 2π / 3 fixing method is used in which each phase voltage is fixed in turn every 2π / 3 period. When the amplitude of the phase voltage is equal to or greater than a predetermined threshold, each phase voltage is set to π / It is characterized by adopting a π / 3 fixing method that fixes in order every three periods. Normally, this two-phase modulation method adopts the π / 3 fixed method instead of the conventional 2π / 3 fixed method, thereby reducing the switching loss of the inverter, particularly the inverter switching loss in the high torque power running high-speed rotation region. Therefore, when the phase voltage amplitude is small and it is difficult to switch the fixed phase with high accuracy, the 2π / 3 fixed method with high switching accuracy is adopted. It can be carried out.

  A two-phase modulation motor control system according to a fifth aspect of the present invention is the two-phase modulation system in which each phase voltage of the three-phase voltage applied to the three-phase AC motor is fixed in order every predetermined period. When the coordinate point determined by iq and d-axis current id is within a predetermined region including the origin on the two-dimensional plane of the current determined by q-axis current iq and d-axis current id, each phase voltage is 2π / A two-phase modulation method that fixes in order every three periods is adopted, and a π / 3 fixing method that fixes each phase voltage in order every π / 3 period when the coordinate point is outside the predetermined region is adopted. .

  If it does in this way, while having the same effect as the 4th invention, the above-mentioned change can be performed simply and accurately. More specifically, the amplitude of the phase voltage changes from moment to moment for each phase, and there is also an influence of a noise voltage superimposed on the phase voltage, which causes a problem of deterioration in determination accuracy. On the other hand, the q-axis current iq and the d-axis current id are substantially less compared with the amplitude of the phase voltage, and the fluctuation can be detected easily and stably, so that the accuracy in the switching is improved. That is why. The predetermined area is preferably an area corresponding to an area where the amplitude of the phase voltage is equal to or lower than a predetermined level.

  A two-phase modulation motor control system according to a sixth aspect of the present invention is the two-phase modulation system in which each phase voltage of the three-phase voltage applied to the three-phase AC motor is fixed in order for each predetermined period. The torque and rotation of the three-phase AC motor When the coordinate point determined by the number is within a predetermined region including the origin on the two-dimensional plane of the motor output determined by the torque and the number of rotations, each phase voltage is fixed in order every 2π / 3 period 2 A phase modulation method is employed, and a π / 3 fixed method is employed in which each phase voltage is fixed in turn every π / 3 period when the coordinate point is outside the predetermined region.

  In this way, the same effects as those of the third invention can be obtained, and the above switching can be performed easily and accurately, and the π / 3 fixed method having a large effect of reducing the switching loss can be utilized to the maximum extent. Can do. More specifically, the amplitude of the phase voltage changes from moment to moment for each phase, and there is also an influence of a noise voltage superimposed on the phase voltage, which causes a problem of deterioration in determination accuracy. On the other hand, the torque and the rotational speed are essentially less changed than the amplitude of the phase voltage, and the fluctuation can be detected easily and stably, so that the accuracy in the switching is improved and π / 3 is fixed. The controllable range of the system can be expanded appropriately. The predetermined area is preferably an area corresponding to an area where the amplitude of the phase voltage is equal to or lower than a predetermined level.

  In aspect 1 of the sixth aspect of the invention, the two-dimensional plane of the motor output is constituted by a forward rotational force quadrant, a forward rotational regeneration quadrant, a reverse rotational force quadrant, and a reverse rotational regeneration quadrant, and the magnitude and direction of the rotational speed are equal. In addition, the threshold value (absolute value) for the torque is set to be larger in the regenerative quadrant than the power running quadrant, so that the phase voltage amplitude is substantially equal even though the torque and the rotational speed are used. When the value is less than or equal to the value, 2π / 3 fixed type two-phase modulation driving can be performed.

  In aspect 2 which is a preferred aspect of the sixth invention, the shape of the predetermined region is substantially rotationally symmetric in the forward rotational force quadrant and the reverse rotational force quadrant, and therefore, in the forward rotational force quadrant and the reverse rotational force quadrant When the amplitude of the phase voltage becomes equal to or less than a predetermined threshold value, 2π / 3 fixed type two-phase modulation drive can be performed. The shape of the predetermined region is 2π / 3 fixed type two-phase modulation drive when the amplitude of the phase voltage is equal to or less than a predetermined threshold value in the forward rotation regeneration quadrant and the reverse rotation regeneration quadrant. Can do.

  In a preferred aspect of the fifth or sixth invention, the 2π / 3 fixing method fixes the upper arm element off of a pair of the upper arm element and the lower arm element that outputs the phase voltage to be fixed, This is carried out with the lower arm element fixed on. In this way, even when the upper arm element is composed of an NMOS transistor, IGBT, or the like, like the lower arm element of the inverter, a bootstrap circuit (described later) that supplies a power supply voltage to the driver circuit that drives the upper arm element. There is no problem in operation.

  In a preferred aspect of the fifth or sixth invention, immediately after starting the inverter that outputs the three-phase voltage to the three-phase AC motor, all upper arm elements are turned off and all lower arm elements are turned on. In this way, even when the upper arm element is composed of an NMOS transistor, IGBT, or the like, like the lower arm element of the inverter, a bootstrap circuit (described later) that supplies a power supply voltage to the driver circuit that drives the upper arm element. There is no problem in operation.

  In a preferred aspect of the fifth or sixth invention, when the inverter that outputs the three-phase voltage to the three-phase AC motor is stopped, all the upper arm elements are turned off and all the lower arm elements are turned on to enter a standby state. To do. In this way, even when the upper arm element is composed of an NMOS transistor, IGBT, or the like, like the lower arm element of the inverter, a bootstrap circuit (described later) that supplies a power supply voltage to the driver circuit that drives the upper arm element. There is no problem in operation.

  In a preferred aspect of the fifth or sixth invention, when it is detected that an inverter that outputs the two-phase modulated three-phase voltage to the three-phase AC motor is abnormal, all upper arm elements are turned on, All the lower arm elements are turned off and the drive is prohibited. In this way, even when the upper arm element is composed of an NMOS transistor, IGBT, or the like, like the lower arm element of the inverter, a bootstrap circuit (described later) that supplies a power supply voltage to the driver circuit that drives the upper arm element. Since the built-in capacitor is not charged, there is no problem.

  The bootstrap circuit includes a power supply circuit that supplies a power supply voltage to the driver circuit for driving the lower arm element, and a capacitor that supplies the power supply voltage to the driver circuit for driving the upper arm element through a diode. It means a circuit in which the lower power supply terminal of the driver circuit for driving the arm element is connected to the connection point between the upper arm element and the lower arm element.

  Furthermore, if the above-described two-phase modulation motor control method is applied to an automobile travel motor, excellent safety can be realized in addition to a large loss reduction effect.

  Preferred embodiments of the invention are illustrated by the following examples. Of course, the present invention is not limited by the following examples, and it is a matter of course that all embodiments embodying the idea of the present invention fall within the scope of the present invention.

Preferred embodiments of a motor device using the motor control device of the present invention will be described below with reference to the drawings.
(overall structure)
The configuration of this motor device is shown in FIG. 1 which is a block diagram. Reference numeral 1 denotes a DC power source, 2 denotes a driving device, 3 denotes a three-phase synchronous motor, 4 and 5 denote two current sensors for detecting a phase current, and 6 denotes a motor rotation position detecting means for detecting a motor rotation angle. The drive device 2 converts the DC power supplied from the DC power source 1 by PWM control of the switching elements into three-phase AC power and supplies the three-phase synchronous motor 3 to each other, and the switching elements of the inverter 7 are intermittently connected. And a control circuit 8 for controlling. The inverter 7 has a total of 6 element units in which IGBTs and flywheel diodes are connected in parallel. Each IGBT is classified into an upper arm element on the high potential side and a lower arm element on the low potential side. Of course, MOS transistors may be used as switching elements instead of IGBTs. Since the configuration and operation of this type of three-phase inverter are well known, further explanation is omitted.

The motor rotation position detecting means can be omitted by calculating the electrical angle θ (phase) based on the phase current or the like.
(Basic configuration and operation of the control circuit 8)
The configuration and basic operation of the control circuit 8 will be described with reference to FIG. FIG. 2 is a block circuit diagram showing a functional configuration of the control circuit 8.

  The control circuit 8 includes a motor rotation number calculation means 81, a dq-axis current generation means 82, a three-phase voltage command generation means 83, a two-phase modulation voltage command generation means 84, a PWM signal generation means 85, and a switching gate driver 86.

  The motor rotation number calculation means 81 calculates the motor rotation number Nmot based on the rotation angle θ input from the motor rotation position detection means 6 and outputs it to the dq axis current generation means 82. The dq-axis current generating means 82 uses a d-axis current id * and a q-axis current iq * as currents to flow to the motor 3 from the torque command trq * indicating the magnitude and direction of the input torque and the motor rotation speed Nmot. A certain dq axis current command is calculated. The three-phase voltage command generation means 83 calculates a d-axis current id and a q-axis current iq which are actual dq-axis currents obtained by converting the detected actual currents Iv and Iw by dq-axis, and current deviation Δid for each coordinate axis. , Δiq, and the three-phase voltage commands U *, V *, W * that should converge the calculated current deviations Δid, Δiq to 0 are obtained by PI calculation and output to the two-phase modulation voltage command generating means 84.

  The two-phase modulation voltage command generation means 84 forms a two-phase modulation voltage command U **, V **, W ** based on the input three-phase voltage command U *, V *, W * to generate a PWM signal. The PWM signal generation means 85 generates three-phase PWM voltages VU, VV, VW corresponding to the input two-phase modulation voltage commands U **, V **, W **.

These three-phase PWM voltages VU, VV, and VW are respectively amplified by the switching gate driver 86 to obtain six gate voltages UU, UL, VU, VL, WU, and WL. It is output individually to the gate electrode. Since the basic configuration and operation of the control circuit 8 are already well known as a two-phase modulation motor control device, further explanation is omitted.
(Description of two-phase modulation voltage command generation means 84)
Next, the two-phase modulation voltage command generating means 84 that characterizes the present invention will be described below with reference to FIG. The two-phase modulation voltage command generation unit 84 includes a two-phase modulation system switching determination unit 87, a fixed phase determination unit 88, and a voltage command calculation unit 89.

  The two-phase modulation method switching determining means 87 determines the two-phase modulation method to be adopted at present by substituting the input torque command trq * and the motor rotation speed Nmot into a map stored in advance. The details of the two-phase modulation system switching determination means 87 will be described later.

  The fixed phase determination means 88 is a phase to be fixed based on the three-phase voltage commands U *, V * and W * by the fixed phase determination suitable for the two-phase modulation method determined by the two-phase modulation method switching determination means 87. And the timing. Details of the stationary phase determination means 88 will be described later.

  The voltage command calculation means 89 fixes the phase voltage command to be fixed among the three-phase voltage commands U *, V *, W * to a predetermined potential level determined by the current two-phase modulation method, and the remaining two Change the phase voltage command to maintain the interphase voltage.

  Thereby, the two-phase modulation voltage command generation means 84 converts the input three-phase voltage commands U *, V *, W * into two-phase modulation voltage commands U **, V **, W **. 3 shows the waveforms of the three-phase voltage commands U *, V *, and W *, FIG. 4 shows the two-phase modulation waveform of the 2π / 3 fixed method, and FIG. 6 shows the two-phase modulation waveform of the π / 3 fixed method. Shown in FIG. 4 shows a system in which the upper arm element of the stationary phase is always turned on in order to fix the stationary phase, that is, the phase voltage command to be fixed to the highest potential (upper arm fixing system), and FIG. A method of always turning on the lower arm element of the stationary phase in order to fix the phase voltage command to be fixed at the lowest potential (lower arm fixing method) is shown. As the 2π / 3 fixing method to be adopted in this embodiment, the lower arm fixing method is adopted. However, the upper arm fixing method may be adopted or may be adopted alternately.

In the 2π / 3 fixing method of this embodiment, the reason why the lower arm fixing method is adopted is that if the lower arm element of the inverter is turned on and the upper arm element is turned off, the upper arm element driving driver circuit 100 is changed. This is because even if the power supply circuit is constituted by a bootstrap circuit as shown in FIG. 7, it is possible to prevent a voltage drop of the power supply, thereby realizing cost reduction. That is, when the lower arm element 101 is turned on, the potential at the connection point between the lower arm element 101 and the upper arm element 102 is lowered, so that the power supply circuit for driving the upper arm element driving driver circuit 100 for driving the upper arm element 102 is used. This is because the capacitor 103 is charged through the diode D by the voltage VN of the power supply 104 for the lower arm element driving driver circuit.
(Description of the two-phase modulation system switching determination means 87)
The two-phase modulation system switching determination means 87 switches between a 2π / 3-fixed 2-phase modulation system and a π / 3-fixed 2-phase modulation system under operating conditions. In this embodiment, the torque command trq * and the motor rotation speed Nmot that are input are substituted into the map shown in FIG. 8 that is stored in advance to switch between the 2π / 3 fixed method and the π / 3 fixed method. FIG. 8 shows the operating range on the two-dimensional plane of the motor output with the torque command as the vertical axis and the rotational speed as the horizontal axis. The region including the origin is the region operating in the 2π / 3 fixed system, and the region outside it is The area | region which drive | operates by (pi) / 3 fixed system is shown. In FIG. 8, the region of the 2π / 3 fixed method in the second and fourth quadrants that are regenerative quadrants is set larger than the region of the 2π / 3 fixed method in the first and third quadrants that are powering quadrants. This is because the phase voltage command tends to be smaller in the regenerative quadrant even if the torque has the same absolute value as in the power quadrant.

The operation of the two-phase modulation system switching determination means 87 is shown as a flowchart in FIG. Of course, the two-phase modulation system switching determination means 87 can be executed by hardware processing instead of such software operation.
(Description of stationary phase determination means 88)
The stationary phase determination means 88 fixes the phase voltage command according to the current fixing method selected from the 2π / 3 fixing method and the π / 3 fixing method. As shown in Fig. 4, the upper arm fixed 2π / 3 fixed method fixes the maximum phase voltage command to 1 (Duty 100%) among the three-phase voltage commands U *, V *, and W *. The remaining two phase voltage commands are shifted so that the interphase voltage becomes a sine wave. As shown in FIG. 5, the lower arm 2π / 3 fixing method fixes the minimum phase voltage command to 0 (Duty 0%) among the three-phase voltage commands U *, V *, W *. The remaining two phase voltage commands are shifted so that the interphase voltage becomes a sine wave. As shown in FIG. 6, in the π / 3 fixed method, a phase voltage command of one phase having a different polarity among the three phase voltage commands U *, V *, and W * is set to 1 (Duty 100%) or 0. Fix to (Duty 0%) and shift the remaining two-phase voltage commands. For example, when U *> 0 and V *, W * <0, U * is fixed to 1 (Duty 100%), and V * and W * are shifted so as to maintain the interphase voltage with U *. When U * <0 and V *, W *> 0, U * is fixed at 0 (Duty 0%), and V * and W * are shifted so as to maintain the interphase voltage with U *. V * and W * are similarly performed.

According to this embodiment, since the two-phase modulation can be performed with less switching frequency and smaller switching loss than the three-phase modulation in the entire operation region, the inverter efficiency can be improved. In addition, the 2π / 3 fixed method that can reliably perform the two-phase modulation in the region where the amplitude of the phase voltage indicated by the map of the torque and the rotational speed is small and the implementation of the π / 3 fixed method is difficult is adopted. Since the π / 3 fixed method with small switching loss is adopted in the other operating areas, the switching can be performed stably and accurately, and the π / 3 fixed method having the large effect of reducing the switching loss is used to the maximum. be able to.
(Modification 1)
When the inverter is stopped, it is preferable to turn on all three lower arm elements of the inverter and turn off all three upper arm elements as shown in FIG. In this manner, in the bootstrap circuit shown in FIG. 7 described above, the capacitor 103 for driving the upper arm element driving driver circuit 100 that drives the upper arm element 102 when all the lower arm elements 101 are turned on becomes lower. The battery can be rapidly charged by the voltage VN of the power supply 104 for the arm element driving driver circuit, and the next inverter can be driven at an early stage.
(Modification 2)
Immediately after starting the inverter, it is preferable that all three lower arm elements of the inverter are turned on and all three upper arm elements are turned off for a predetermined time for charging the capacitor 103 as shown in FIG. In this manner, in the bootstrap circuit shown in FIG. 7 described above, the capacitor 103 for driving the upper arm element driving driver circuit 100 that drives the upper arm element 102 when all the lower arm elements 101 are turned on becomes lower. The battery can be rapidly charged by the voltage VN of the power supply 104 for the arm element driving driver circuit, and the next inverter can be driven at an early stage. The same is true immediately after startup.
(Modification 3)
In addition, as shown in FIG. 12, when an inverter or motor abnormality is detected by any means, all lower arm elements 101 are turned off and all upper arm elements 102 are turned off in the bootstrap circuit shown in FIG. It is preferable to turn it off. In this way, the upper arm element 102 of the inverter cannot be turned on by discharging the capacitor 103 of the bootstrap circuit, that is, the upper arm element driving power source, and the safety of prohibiting the operation of the inverter is further ensured.

  A preferred embodiment of a motor apparatus using the motor control apparatus of the present invention will be described below with reference to FIG.

  In the first embodiment, the 2π / 3 fixed method and the π / 3 fixed method are switched based on the map of the torque and the rotational speed, but the amplitudes of the three-phase voltage commands U *, V *, and W * are changed as in the past. You may switch based on. That is, if the amplitude of a predetermined one phase of the three-phase voltage commands U *, V *, W * exceeds a predetermined threshold value, the π / 3 fixed method may be used, and if not, the 2π / 3 fixed method may be used. Of course, in order to reduce the influence of noise or the like, the amplitude of the effective value of the phase voltage command or the amplitude of the low frequency component of the phase voltage command may be employed as the amplitude of the phase voltage command.

  According to this embodiment, since the two-phase modulation can be performed with less switching frequency and smaller switching loss than the three-phase modulation in the entire operation region, the inverter efficiency can be improved.

  A preferred embodiment of a motor apparatus using the motor control apparatus of the present invention will be described below with reference to FIG.

  In the first embodiment, the 2π / 3 fixed method and the π / 3 fixed method are switched based on the map of the torque and the rotational speed. Instead, the q-axis current command output from the dq-axis current generating unit 82 is used. The value Iq * and the d-axis current value Id * may be substituted into the map for switching. For example, on the two-dimensional plane of the current having the q-axis current command value Iq * as the vertical axis and the d-axis current command value Id * as the horizontal axis, the q-axis command value at which the amplitude of the phase voltage command is less than a predetermined threshold value A region including the two-dimensional coordinate point of the current Iq * and the d-axis current id may be a region adopting the 2π / 3 fixing method, and the other operation region may be the π / 3 fixing method. Of course, a map indicating these areas may be determined in advance and stored.

  According to this embodiment, since the two-phase modulation can be performed with less switching frequency and smaller switching loss than the three-phase modulation in the entire operation region, the inverter efficiency can be improved. In addition, two-phase modulation can be reliably performed in a region where the amplitude of the phase voltage indicated by the map of the q-axis current command value Iq * and the d-axis current value Id * is small and it is difficult to implement the π / 3 fixing method. Since the 2π / 3 fixing method is adopted and the π / 3 fixing method with small switching loss is adopted in other operation regions, switching can be performed stably and accurately.

  A preferred embodiment of a motor apparatus using the motor control apparatus of the present invention will be described below with reference to FIG.

  In the first and third embodiments, the 2π / 3 fixed method and the π / 3 fixed method are switched. Alternatively, the π / 3 fixed method and the three-phase modulation may be switched. However, the switching is performed using a map indicating the π / 3 fixed region and the three-phase modulation region indicated by the torque and the rotational speed employed in the first embodiment, or the q-axis current command value Iq * and d employed in the third embodiment. This should be performed using a map indicating the π / 3 fixed region and the three-phase modulation region indicated by the axial current command value Id *. In the case of three-phase modulation, the fixed phase determination unit 88 does not perform the fixed phase, and the voltage command calculation unit 89 outputs the input three-phase voltage commands U *, V *, and W * as they are.

  That is, the region where the amplitude of the phase voltage indicated by the torque and the rotational speed is small, or the region where the amplitude of the phase voltage indicated by the q-axis current command value Iq * and the d-axis current command value Id * is small is Unlike the amplitude itself, it is not a sine wave function, so there is little temporal variation, and it is possible to specify three-phase modulation in an operating region where the phase voltage amplitude is small with high accuracy.

It is a block circuit diagram which shows the whole structure of the apparatus of an Example. It is a block circuit diagram which shows the detailed structure of the two-phase modulation voltage command generation means of FIG. It is a wave form diagram of 3 phase voltage command U *, V *, W *. It is a waveform diagram of a two-phase modulation voltage fixed at 2π / 3 by the upper arm. FIG. 6 is a waveform diagram of a two-phase modulation voltage fixed at 2π / 3 by the lower arm. FIG. 6 is a waveform diagram of a two-phase modulation voltage fixed at π / 3. It is a circuit diagram which shows an example of the bootstrap circuit for an upper arm element drive of an inverter. It is a figure which shows the area | region of (pi) / 3 fixed system and 2 (pi) / 3 fixed system. It is a flowchart which shows the function of a two-phase modulation system switch determination means. It is a flowchart which shows the process which makes a lower arm all the ON state and an upper arm all OFF state immediately after an inverter stop. It is a flowchart which shows the process which makes a lower arm all the ON state and an upper arm all OFF state immediately after inverter starting. It is a flowchart which shows the process which makes an upper arm all on state and a lower arm all off state at the time of abnormality detection.

Explanation of symbols

1 DC power supply 2 Motor drive device 3 Motor (3-phase synchronous motor)
4 Current sensor 5 Current sensor 6 Motor rotation position detection means 7 Inverter 8 Control circuit 81 Motor rotation speed calculation means 82 Axis current generation means 83 Phase voltage command generation means 84 Phase modulation voltage command generation means 85 Signal generation means 86 Switching gate driver 87 Phase modulation system switching determination means 88 Fixed phase determination means 89 Voltage command calculation means 100 Upper arm element driver circuit 101 Lower arm element 102 Upper arm element 103 Capacitor 104 Lower arm element driver circuit power supply

Claims (16)

In the two-phase modulation method in which each phase voltage of the three-phase voltage applied to the three-phase AC motor is fixed in order for each predetermined period,
When the amplitude of the phase voltage is less than a predetermined threshold, the two-phase modulation method is interrupted to output the three-phase voltage,
A two-phase modulation method, which employs a π / 3 fixing method in which each phase voltage is fixed in turn every electrical angle π / 3 period when the amplitude of the phase voltage is a predetermined threshold value or more. In the two-phase modulation method in which each phase voltage of the three-phase voltage applied to the three-phase AC motor is fixed in order for each predetermined period,
The coordinate point defined by the q-axis current iq and the d-axis current id of the three-phase AC motor is within a predetermined region including the origin on the two-dimensional plane of the current determined by the q-axis current iq and the d-axis current id. The two-phase modulation method, wherein the two-phase modulation method is interrupted in some cases to output the three-phase voltage, and the two-phase modulation is adopted when the coordinate point is outside the predetermined region. In the two-phase modulation method in which each phase voltage of the three-phase voltage applied to the three-phase AC motor is fixed in order for each predetermined period,
When the coordinate point determined by the torque and the rotational speed of the three-phase AC motor is within a predetermined region including the origin on the two-dimensional plane of the motor output determined by the torque and the rotational speed, the two-phase modulation method is used. The two-phase modulation method is characterized by adopting two-phase modulation when the three-phase voltage is interrupted and the coordinate point is outside the predetermined region. The two-phase modulation system according to claim 2 or 3,
A two-phase modulation method that employs π / 3-fixed two-phase modulation that fixes each phase voltage in turn every electrical angle π / 3 period when the coordinate point is outside the predetermined region. The two-phase modulation system according to claim 3,
The two-dimensional plane of the motor output is composed of a forward rotational force quadrant, a forward rotational regeneration quadrant, a reverse rotational force quadrant, and a reverse rotational regeneration quadrant.
The two-phase modulation method, wherein the threshold value (absolute value) for torque is set larger in the regenerative quadrant than in the powering quadrant when the magnitude and direction of the rotational speed are equal. The two-phase modulation system according to claim 3,
The two-phase modulation is characterized in that the shape of the predetermined region is substantially rotationally symmetric in the forward rotational force quadrant and the reverse rotational force quadrant, and is substantially rotationally symmetric in the forward rotational regeneration quadrant and the reverse rotational quadrant. method. In the two-phase modulation method in which each phase voltage of the three-phase voltage applied to the three-phase AC motor is fixed in order for each predetermined period,
When the amplitude of the phase voltage is less than a predetermined threshold, a 2π / 3 fixing method is adopted in which each phase voltage is fixed in order every electrical angle 2π / 3 period,
A two-phase modulation method, which employs a π / 3 fixing method in which each phase voltage is fixed in turn every electrical angle π / 3 period when the amplitude of the phase voltage is a predetermined threshold value or more. In the two-phase modulation method in which each phase voltage of the three-phase voltage applied to the three-phase AC motor is fixed in order for each predetermined period,
The coordinate point defined by the q-axis current iq and the d-axis current id of the three-phase AC motor is within a predetermined region including the origin on the two-dimensional plane of the current determined by the q-axis current iq and the d-axis current id. In some cases, a two-phase modulation method is used in which each phase voltage is fixed in order every electrical angle 2π / 3 period. When the coordinate point is outside the predetermined region, each phase voltage is electrical angle every π / 3 period. A two-phase modulation method characterized by adopting a π / 3 fixing method in which the signals are fixed in order. In the two-phase modulation method in which each phase voltage of the three-phase voltage applied to the three-phase AC motor is fixed in order for each predetermined period,
When the coordinate point determined by the torque and the rotational speed of the three-phase AC motor is within a predetermined region including the origin on the two-dimensional plane of the motor output determined by the torque and the rotational speed, Employs a two-phase modulation method that fixes in order every 2π / 3 period, and fixes each phase voltage in order every electrical angle π / 3 period when the coordinate point is outside the predetermined region. A two-phase modulation method characterized by adopting a method. The two-phase modulation system according to claim 9,
The two-dimensional plane of the motor output is composed of a forward rotational force quadrant, a forward rotational regeneration quadrant, a reverse rotational force quadrant, and a reverse rotational regeneration quadrant.
The two-phase modulation method, wherein the threshold value (absolute value) for torque is set larger in the regenerative quadrant than in the powering quadrant when the magnitude and direction of the rotational speed are equal. The two-phase modulation system according to claim 9,
The shape of the predetermined region is substantially rotationally symmetric in the forward rotation force quadrant and the reverse rotational force quadrant, and the shape of the predetermined region is substantially rotationally symmetric in the forward rotation regeneration quadrant and the reverse rotation regeneration quadrant. A two-phase modulation system characterized by The two-phase modulation system according to any one of claims 7 to 11,
The upper arm element of the inverter is driven by a bootstrap circuit,
The 2π / 3 fixing method is performed by fixing the upper arm element off of the pair of the upper arm element and the lower arm element that outputs the fixed phase voltage and fixing the lower arm element on. Two-phase modulation method. The two-phase modulation method according to any one of claims 7 to 12,
The upper arm element of the inverter is driven by a bootstrap circuit,
A two-phase modulation method, wherein immediately after starting an inverter that outputs the three-phase voltage to the three-phase AC motor, all upper arm elements are turned off and all lower arm elements are turned on. The two-phase modulation system according to any one of claims 7 to 13,
The upper arm element of the inverter is driven by a bootstrap circuit,
2. A two-phase modulation system characterized in that when the inverter that outputs the three-phase voltage to the three-phase AC motor is stopped, all upper arm elements are turned off and all lower arm elements are turned on to enter a standby state. The two-phase modulation method according to any one of claims 7 to 14,
The upper arm element of the inverter is driven by a bootstrap circuit,
When it is detected that the inverter that outputs the two-phase modulated three-phase voltage to the three-phase AC motor is abnormal, all the upper arm elements are turned on and all the lower arm elements are turned off. A two-phase modulation method that is in a prohibited state. The two-phase modulation system according to any one of claims 1 to 15,
The three-phase AC motor is a traveling motor for automobiles, and is a two-phase modulation method.

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