JP2007020331A - Method for controlling inverter devices - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the effective value of composite current to prevent rise in IPM temperature and degradation in withstand voltages even when the two currents constituting the composite current are close to each other in frequency. <P>SOLUTION: A control method for inverter devices is such that a composite current is generated by adding together a current with a frequency of f<SB>1</SB>and a current with a frequency of f<SB>2</SB>. When the frequency of f<SB>1</SB>and the frequency of f<SB>2</SB>are close to each other, a compensating current with a frequency of (f<SB>1</SB>+f<SB>2</SB>)/2 is added to the composite current. Since the composite current oscillates at a frequecy of (f<SB>1</SB>+f<SB>2</SB>)/2 and further oscillates at a frequency of (f<SB>1</SB>-f<SB>2</SB>)/2, a problem arises when a compensating current with a frequency of (f<SB>1</SB>+f<SB>2</SB>)/2 is added so as to cancel out the oscillation with a frequency of (f<SB>1</SB>+f<SB>2</SB>)/2. When the polarity of the oscillation with a frequency of (f<SB>1</SB>-f<SB>2</SB>)/2 of the composite current is changed, the compensating current added to cancel out the oscillation is conversely added. To cope with this, the polarity of the compensating current with a frequency of (f<SB>1</SB>+f<SB>2</SB>)/2 is inverted each time the polarity of the oscillation with a frequency of (f<SB>1</SB>-f<SB>2</SB>)/2 is changed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for controlling an inverter device that is arranged between a battery that is a direct current power source and a rotating electrical machine that is driven by alternating current, and that performs mutual conversion between direct current and alternating current.

Conventionally, as an example of a rotating electrical machine configured at least from a stator and an outer rotor provided on the outside of the stator, a cylindrical stator is sandwiched, and an outer rotor and an inner rotor are disposed on the inner and outer circumferences. A rotating electrical machine having a multi-axis multilayer structure in which the outer rotor and the inner rotor can be independently controlled to rotate by flowing a composite current through the multiphase coil is known (see, for example, Patent Document 1).
JP 11-356100 A

In the rotating electrical machine having the multi-axis multilayer structure configured as described above, a composite current having two frequency components is used to drive the rotating electrical machine. However, in the conventional inverter device for driving the rotating electrical machine, the current having the frequency f ₁ and the frequency When a composite current in which the current of f ₂ is added is energized, a beat occurs when the values of f ₁ and f ₂ are close. The beat current has a short period of 2 / (f ₁ + f ₂ ) and a long period of 2 / (f ₁ −f ₂ ). If the period of 2 / (f ₁ −f ₂ ) is long, the time during which the current effective value is large is continued for a long time, so that the temperature of the intelligent power module (IPM) constituting the inverter device increases and the breakdown voltage decreases. There was a problem.

If the amplitude of the current at frequency f ₁ is I ₁ and the amplitude of the current at frequency f ₂ is I ₂ , the maximum amplitude of the composite current is I ₁ + I ₂ , and the surge voltage increases, causing the IPM to break down. There was a problem of being affected by function stoppage and deterioration.

  The present invention has been made in view of such problems, and an object of the present invention is to reduce the effective value of the composite current even when the frequencies of two currents constituting the composite current are close to each other. An object of the present invention is to provide a method for controlling an inverter device that can prevent the temperature from increasing and the breakdown voltage from decreasing, and the surge voltage from increasing to prevent the IPM from causing dielectric breakdown.

To achieve the above object, a first invention is a control method for inverter apparatus for generating a composite current combined addition of the current and the current of a frequency f ₂ frequency f _1, determined from the frequency f ₁ and frequency f _2, A compensation current having a frequency different from the frequency f ₁ and the frequency f ₂ is added to the composite current. The second invention is characterized in that in the first invention, the frequency of the compensation current is (f ₁ + f ₂ ) / 2, and in the third invention, in the first or second invention, the amplitude is the composite current, the frequency _(f 1 _-f 2) / 2 of each time the polarity of the vibration is changed but that oscillates at a frequency _(f 1 _-f 2) / 2 while oscillating at a frequency _{(f 1 + f 2) /} 2 The polarity of the compensation current is changed.

The fourth invention is a control method for an inverter device that generates a composite current including a plurality of frequency f _k (k = 1, 2, 3...) Components, and the frequency (f _i + f _j ) / 2 ( i ≠ j), and at least one compensation current capable of reducing the effective value of the composite current is added to the composite current.

  According to a fifth invention, in any one of the first to fourth inventions, the amplitude, electrical angular frequency, and phase at which the effect of the compensation current is maximized are obtained by calculation, and the obtained amplitude, electrical angular frequency, and phase are obtained. Further, the sixth invention is characterized in that in any one of the first to fifth inventions, the temperature of the IPM is measured, and when the temperature exceeds a certain temperature, the compensation current is added. It is preferable to match.

According to the first invention, by adding together the compensation current having a frequency different from f ₁ and f ₂ so as to cancel the amplitude of the combined current obtained by adding the current of frequency f _{1 and} the current of frequency f ₂ , A state where the effective current value is large for a long time can be avoided. This prevents the IPM from becoming hot. Further, since the current amplitude is also reduced, the surge voltage is reduced, an inexpensive IPM having a low withstand voltage can be used, or the DC power supply voltage can be increased.

Further, since the composite current vibrates at the frequency (f ₁ + f ₂ ) / 2 when the frequency f ₁ and the frequency f ₂ are close, according to the second invention, the vibration of the frequency (f ₁ + f ₂ ) / 2 is caused. By adding a compensation current having a frequency (f ₁ + f ₂ ) / 2 so as to cancel out, a state where the current effective value is large for a long time can be avoided, and the IPM is prevented from becoming high temperature. Further, since the current amplitude is also reduced, the surge voltage is reduced, an inexpensive IPM having a low withstand voltage can be used, or the DC power supply voltage can be increased.

Further, when the frequency f ₁ is close to the frequency f ₂ , the composite current vibrates at the frequency (f ₁ −f ₂ ) / 2 while oscillating at the frequency (f ₁ + f ₂ ) / 2. Therefore, the frequency (f ₁ + f ₂ ) When a compensation current having a frequency (f ₁ + f ₂ ) / 2 is applied so as to cancel the vibration of ₂ ) / 2, it is canceled when the polarity of the vibration of the frequency (f ₁ -f ₂ ) / 2 of the composite current is changed. On the contrary, the compensation current added to is added. According to the third aspect of the invention, the polarity of the compensation current at the frequency (f ₁ + f ₂ ) / 2 is inverted every time the polarity of the vibration at the frequency (f ₁ -f ₂ ) / 2 is changed. The effective current value and current amplitude can be reduced.

According to the fourth aspect of the invention, by adding a compensation current of a frequency _{f 3} to the combined current consisting of the frequency _{f 1} and frequency _{f 2,} the frequency _{f 2} and the frequency _{f 3,} while the frequency _{f 3} and the frequency _{f 1} Even if a beat occurs, whether or not a reduction in the effective current value occurs is obtained by calculation. If a decrease in the effective current value occurs, the frequency (f ₂ + f) is used for the beat between f ₂ and f _{3. 3} ) / 2 compensation current of frequency (f ₃ + f ₁ ) / 2 is applied to the beat between f ₃ and f ₁ to avoid a state where the current effective value is large for a long time. Can do. This prevents the IPM from becoming hot. Further, since the current amplitude is also reduced, the surge voltage is reduced, an inexpensive IPM having a low withstand voltage can be used, or the DC power supply voltage can be increased.

  Further, according to the fifth aspect, since the optimum values of the amplitude, frequency, and phase of the compensation current to be applied are obtained by calculation based on information such as the amplitude, frequency, and phase of the composite current, the long-term current effective value is obtained. The effect of alleviating the large state and reducing the current peak can be maximized.

  Furthermore, when adding a compensation current to reduce the effective current value, calculating the optimum value of the amplitude of the compensation current or calculating the time to change the polarity of the compensation current will impose a burden on the control system. However, according to the sixth invention, the effective current value and the current amplitude can be reduced without always placing a burden on the control system by performing the effective current value reduction control only when the IPM temperature rises. .

  Before explaining the control method of the inverter device of the present invention, a rotating electric machine having a multi-shaft multilayer structure having two rotors inside and outside driven by the inverter device according to the present invention will be described first. FIG. 1 is an overall view of a hybrid drive unit to which a multi-axis multilayer motor as an example of a rotating electrical machine to be driven by an inverter device is applied. In FIG. 1, E is an engine, M is a multi-shaft multilayer motor, G is a Ravigneaux type planetary gear train, D is a drive output mechanism, 1 is a motor cover, 2 is a motor case, 3 is a gear housing, 4 is a front cover is there.

  The engine E is a main power source of the hybrid drive unit, and the engine output shaft 5 and the second ring gear R2 of the Ravigneaux type planetary gear train G are connected via a rotation fluctuation absorbing damper 6 and a multi-plate clutch 7. ing.

  The multi-axis multilayer motor M is a sub-power source having two motor generator functions although it is one motor in appearance. This multi-shaft multilayer motor M is fixed to the motor case 2 and has a stator S as a fixed armature wound with a coil, an inner rotor IR disposed inside the stator S and embedded with permanent magnets, and the stator The outer rotor OR, which is disposed outside the S and has a permanent magnet embedded therein, is arranged in three layers on the same axis. A first motor hollow shaft 8 fixed to the inner rotor IR is connected to a first sun gear S1 of a Ravigneaux type planetary gear train G, and a second motor shaft 9 fixed to the outer rotor OR is a Ravigneaux type planetary gear. It is connected to the second sun gear S2 of the row G.

  The Ravigneaux-type compound planetary gear train G is a planetary gear mechanism having a continuously variable transmission function that changes the gear ratio steplessly by controlling two motor rotation speeds. The Ravigneaux type planetary gear train G includes a common carrier C that supports the first pinion P1 and the second pinion P2 that mesh with each other, a first sun gear S1 that meshes with the first pinion P1, and a second sun gear that meshes with the second pinion P2. It has five rotational elements of S2, a first ring gear R1 that meshes with the first pinion P1, and a second ring gear R2 that meshes with the second pinion P2. A multi-plate brake 10 is interposed between the first ring gear R1 and the gear housing 3. An output gear 11 is connected to the common carrier C.

  The drive output mechanism D includes an output gear 11, a first counter gear 12, a second counter gear 13, a drive gear 14, a differential 15, and drive shafts 16 and 16. The output rotation and output torque from the output gear 11 pass through the first counter gear 12, the second counter gear 13, the drive gear 14, and the differential 15, and are transmitted from the drive shafts 16 and 16 to the drive wheels (not shown). The

  That is, the hybrid drive unit connects the second ring gear R2 and the engine output shaft 5, connects the first sun gear S1 and the first motor hollow shaft 8, and connects the second sun gear S2 and the second motor shaft 9 to each other. And the output gear 11 is connected to the common carrier C.

The present invention relates to a method of controlling an inverter device for driving a rotating electrical machine having a multi-axis multilayer structure including two rotors inside and outside. In an inverter device for driving a rotating electrical machine, when a composite current obtained by adding a current of a frequency f _{1 and} a current of a frequency f ₂ is energized, a beat occurs when the values of the frequencies f ₁ and f ₂ are close to each other. Although the time when the current effective value is large continues for a long time, the present invention has a frequency different from f ₁ and f ₂ so as to cancel the amplitude of the composite current even when the frequencies of the two currents constituting the composite current are close. The effective value of the composite current is reduced by adding the compensation current. With this configuration, the present invention can prevent the temperature of the IPM from increasing and the breakdown voltage from decreasing, and the surge voltage from increasing to prevent the IPM from causing dielectric breakdown or the like.

Hereinafter, the control method of the inverter apparatus of this invention is demonstrated in detail. FIG. 2 is a control system diagram of a motor having a multi-axis multilayer structure. Here, an example in which the inner rotor is driven with a six-phase current and the outer rotor is driven with a three-phase current will be described. The phase current value of the motor 33 detected by the current sensor 32 is separated into the inner part of the frequency f _{1 and} the outer part of the frequency f ₂ by the phase current separating means 27, and the inner six-phase current value is 6φ → dq axis. The conversion means 25 converts it into a dq-axis current value, and the outer three-phase current value is converted into a dq-axis current value at 3φ → dq-axis conversion means 26.

  When the inner dq axis current target value is given, the inner PI control means 21 performs current PI control so that the actual dq axis current value from the 6φ → dq axis conversion means 25 approaches the inner dq axis current target value, The inner dq axis voltage command value is calculated. When the outer dq-axis current target value is given, outer PI control means 22 performs current PI control so that the actual dq-axis current value approaches the outer dq-axis current target value, and calculates the outer dq-axis voltage command value. . Further, the compensation current calculation means 19 inputs the inner 6-phase current value and the outer 3-phase current value from the phase current separation means 27, and determines whether or not to generate a compensation current for reducing the effective value of the composite current. If it is determined that a compensation current is to be generated, a compensation dq axis voltage command value is calculated.

  The inner dq axis voltage command value calculated by the inner PI control means 21 is converted into an inner six-phase voltage command value by the dq axis → 6φ conversion means 23, and the outer dq axis voltage command value calculated by the outer PI control means is The compensation dq axis voltage command value converted by the dq axis → 3φ conversion means 24 into the outer three-phase voltage command value and calculated by the compensation current calculation means 19 is the compensation phase voltage command value by the dq axis → phase voltage conversion means 20. Is converted to

The adding means 28 adds the inner 6-phase voltage command value, the outer 3-phase voltage command value, and the compensation phase voltage command value, and the duty generation means 29 generates the duty of each phase. The gate signal generation unit 30 generates a PWM signal for controlling the P side and the N side of the inverter device 31 from the pulse generated by the duty generation unit 29 and drives the inverter device 31. From the inverter device 31 comprises a motor 33, the current at which the current of the current and the frequency _{f 2} frequency _{f 1} is added together, determined from the frequency _{f 1} and frequency _{f 2,} a frequency different from the frequency _{f 1} and frequency _{f 2} A composite current in which the compensation current is added is applied.

図３は、うなりを生じた場合の複合電流の一例を示しており、Ｉ_１＝Ｉ_２＝１００〔Ａ〕、ω_１＝２２、ω_２＝２０の場合の複合電流を示している。横軸は周期〔ｓ〕、縦軸は電流振幅〔Ａ〕である。 Next, the fact that the effective value of the composite current can be reduced will be described using mathematical expressions.
A composite current formed by adding the current having the amplitude I ₁ and the angular velocity ω _{1 and} the current having the amplitude I ₂ and the angular velocity ω ₂ is expressed by the following equation (1).

FIG. 3 shows an example of the composite current when the beat occurs, and shows the composite current when I ₁ = I ₂ = 100 [A], ω ₁ = 22, and ω ₂ = 20. The horizontal axis is the period [s], and the vertical axis is the current amplitude [A].

From the equation (1) and FIG. 3, it can be seen that the composite current oscillates at an angular velocity (ω ₁ −ω ₂ ) / 2 and a cos at an angular velocity (ω ₁ + ω ₂ ) / 2. . Here, in order to reduce the current amplitude, the current 3 having the angular velocity (ω ₁ + ω ₂ ) / 2 and the amplitude I ₃ is added to or subtracted from the equation (1) as a compensation current. That is, when the value of cos in the first term on the right side of the equation (1) is positive, the current 3 is decreased, and when the value is negative, the current 3 is added.

Therefore, when one period of vibration having an angular velocity (ω ₁ −ω ₂ ) / 2 is T, the value of cos is 0 ≦ t ≦ (1/4) T and (3/4) T ≦ t ≦ T. Since it is positive, the current 3 is subtracted from the equation (1). As a result, Expression (2) is obtained.

In (1/4) T ≦ t ≦ (3/4) T, since the value of cos is negative, the current 3 is added to the equation (1). As a result, Equation (3) is obtained.

Next, criteria for determining whether or not to apply the current 3 will be described. FIG. 4 is a flowchart for determining whether or not to apply the current 3. First, to calculate the current effective value I _a in the case of adding the current 3, the current effective value I _b for the absence of added current 3. Next, compare the current effective value I _a and the current effective value I _b, when towards the current effective value I _b is greater than the current effective value I _a is the switching time of the acceleration of the current 3, the respective feeder lines After calculating the phase of the flowing current 3, the current 3 is adjusted. When the current effective value I _a is the current effective value I _b above, nothing added.

As an example, the square of the current effective value when the current 3 is applied is calculated in the section of (1/4) T ≦ t ≦ (3/4) T.

The effective current value when the current 3 is not applied is expressed as follows.

式（６）で求められる値が正ならば、電流３を加えることで電流実効値が減少することになる。 Therefore, the amount of decrease in the effective current value due to the addition of the current 3 is calculated by subtracting the equation (4) from the equation (5) to obtain the square root. The square of the decrease is calculated as follows.

If the value obtained by the equation (6) is positive, the current effective value is reduced by adding the current 3.

Next, how to determine the amplitude of the current 3 that maximizes the effective value reduction amount will be described. When the amplitude I ₁ , the angular frequency ω ₁ , the amplitude I _{2 of the} current ₂ , and the angular frequency ω ₂ are substituted into the equation (6) and the values are positive, the equation (6) is converted into the amplitude I _{3 of the} current _3. Differentiate with respect to. By determining the amplitude I ₃ when taking the maximum value, the amplitude I ₃ to the maximum effective value reduction amount obtained.

Especially in the case of ω ₁ ≈ω ₂ , the equation (6) is approximated to the equation (7).

となる。 Differentiating with respect to the amplitude I _{3 by} setting the right side of the equation (7) to 0,

It becomes.

となる。 Therefore, when the amplitude I ₃ when taking the extreme value is obtained,

It becomes.

Next, consider the case where a plurality of currents are added to the composite current. When the current 3 is added to the composite current composed of the current 1 and the current 2, the following equation (10) is obtained, and there is a difference between the current 2 and the current 3 and between the current 3 and the current 1.

Therefore, as shown in Equation (11), the current amplitude is I ₄ , the angular frequency is the average of ω ₂ and ω ₃ (ω ₃ = (ω ₁ + ω ₂ ) / 2), and the current amplitude is I _5. By adding the current 5 whose angular frequency is the average of ω ₃ and ω ₁ as the compensation current, it may be possible to avoid a state where the effective current value is large for a long time and to reduce the current peak.

  Comparing the amplitudes of the third and fourth terms on the right side of equation (10), and the fifth and sixth terms, the third and fifth terms are larger. Therefore, control is performed so as to reduce the third and fifth terms. Specifically, the current 4 and the current 5 are reduced when the cos values of the third and fifth terms are positive, and are added when negative. The effective current value is calculated and compared for when only current 3 is adjusted and when current 4 and current 5 are adjusted. If the effective current value is reduced by adjusting the currents 4 and 5, the currents 4 and 5 are adjusted. Thereby, the effect of control can be further enhanced as compared with the case where only the current 3 is applied.

  Next, as an example, the phase of the current 3 when the composite current composed of the 6-phase current and the 3-phase current shown in Table 1 is applied to the multiphase coil of the rotating electrical machine will be described. Table 1 shows the phase difference between the currents flowing through the power supply lines when the phase of the current flowing through the power supply line U1 is 0 °.

Formula (1) shows a case where there is no phase difference between the 6-phase current and the 3-phase current. However, since there is a phase difference except for the feeder line U1, the phase difference is also considered. If the phase difference of the six-phase current is α and the phase difference of the three-phase current is β based on the feeder line U1, Equation (1) becomes Equation (12).

である。給電線Ｕ１のように位相差が０の場合、９０°から２７０°までは電流３を加え、０°から９０°と２７０°から３６０°の間は電流３を減じる。給電線Ｖ１の場合は、式（１３）のように給電線Ｕ１の場合より３０°進んでいるから、６０°から２４０°までは電流３を加え、０°から６０°と２４０°から３６０°までの間は電流３を減じる。他の給電線に流す電流３の加減も同様に行う。 Whether to add or reduce the current 3 is determined based on whether the value of cos in the first term of the equation (12) is positive or negative. For example, in the case of the feeder line V1, the parenthesis of cos in the first term of Equation (12) is

It is. When the phase difference is 0 as in the feeder line U1, the current 3 is added from 90 ° to 270 °, and the current 3 is reduced between 0 ° to 90 ° and 270 ° to 360 °. In the case of the power supply line V1, the current 3 is applied from 60 ° to 240 °, and the current 3 is applied from 60 ° to 240 °, as shown in Expression (13), and 0 ° to 60 ° and 240 ° to 360 °. Until then, the current 3 is reduced. The amount of current 3 flowing through the other power supply lines is adjusted in the same manner.

となる。したがって、給電線Ｕ１に加える電流３より９０°位相の遅れた電流３を加える。 Next, the phase difference between the 6-phase current, the 3-phase current and the current 3 constituting the composite current will be considered. The parenthesis of sin in the first term of Expression (12) is, for example, the case of the feeder line V1

It becomes. Therefore, the current 3 delayed by 90 ° from the current 3 applied to the feeder line U1 is added.

  If the sum of the phase currents does not become zero when adding the current 3 that is the compensation current, the neutral point of each phase cannot be connected. Therefore, it is necessary to use an inverter circuit in which the neutral point is separated as shown in FIG. 6 instead of a normal inverter circuit to which the neutral point is connected as shown in FIG.

  It is also possible to measure the temperature of the intelligent power module (IPM) that constitutes the inverter device and adjust the compensation current when the temperature exceeds a certain temperature. When a compensation current is added to reduce the effective current value, it may be considered that the control system is burdened if the optimum value of the applied current amplitude or the time for changing the phase by 180 ° is calculated. Therefore, the effective current value can be reduced without constantly burdening the control system by performing the effective current value reduction control only when the temperature of the IPM rises. Here, the intelligent power module means that the switching element is reduced in size and loss, modularized to accommodate multiple elements in one package, and intelligent including the base (gate) drive circuit and protection functions, This is a switching circuit designed for

It is a figure which shows an example of the rotary electric machine used as the drive object of an inverter apparatus. It is a control system diagram of a motor having a multi-axis multilayer structure. It is a figure which shows an example of the composite current at the time of producing a beat. It is a flowchart which judges whether a compensation current is applied. It is a figure which shows the normal inverter circuit to which the neutral point was connected. It is a figure which shows the inverter circuit where the neutral point is not connected in order to flow a compensation current.

Explanation of symbols

19 Compensation current calculation means 20 dq axis → phase voltage conversion means 21 inner PI control means 22 outer PI control means 23 dq axis → 6φ conversion means 24 dq axis → 3φ conversion means 25 6φ → dq axis conversion means 26 3φ → dq axis conversion Means 27 Phase current separation means 28 Addition means 29 Duty generation means 30 Gate signal generation means 31 Inverter device 32 Current sensor 33 Motor

Claims (6)

The control method of an inverter apparatus for generating a composite current added together with current and current frequency f ₂ frequency f _1, determined from the frequency f ₁ and frequency f _2, compensation having a frequency different from the frequency f ₁ and frequency f ₂ A method for controlling an inverter device, comprising adding a current to the composite current. 2. The method of controlling an inverter device according to claim 1, wherein the frequency of the compensation current is (f ₁ + f ₂ ) / 2. Each time the polarity of vibration of the composite current oscillating at the frequency (f ₁ -f ₂ ) / 2 while the amplitude oscillates at the frequency (f ₁ + f ₂ ) / 2 changes at the frequency (f ₁ -f ₂ ) / 2. 3. The method of controlling an inverter device according to claim 1, wherein the polarity of the compensation current is changed. In the control method of the inverter device that generates a composite current including a plurality of frequency f _k (k = 1, 2, 3...) Components, the inverter device has a frequency (f _i + f _j ) / 2 (i ≠ j), A method for controlling an inverter device, comprising adding one or more compensation currents capable of reducing an effective value of the composite current to the composite current.   5. The amplitude, electrical angular frequency, and phase at which the effect of the compensation current is maximized are obtained by calculation, and the compensation current of the obtained amplitude, electrical angular frequency, and phase is added to the composite current. The control method of the inverter apparatus in any one of. 6. The method of controlling an inverter device according to claim 1, wherein the temperature of the intelligent power module is measured, and when the temperature exceeds a certain temperature, the compensation current is added to the composite current.

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