Specific implementation method
Example 1
Fig. 1 is the formation block diagram of control device that the alternating current motor of example of the present invention is shown.As shown in Figure 1, the control device that three-phase alternating-current motor is controlled to the speed of wanting possesses: the converter apparatus 2 that three-phase alternating current 1 is transformed into direct current, the smmothing capacitor 3 of the direct current output of level and smooth converter apparatus 2, with this smmothing capacitor 3 be arranged in parallel converter apparatus 2 outlet side, the direct current power of converter apparatus 2 is transformed to the DC-to-AC converter 4 of three-phase alternating current again, drive for example synchronous motor of permanent magnet motor etc. of threephase motor 5 with the interchange output of this DC-to-AC converter 4.
Control device as control three-phase alternating-current motor 5 usefulness, current detector 10a, 10b, the 10c of electric current that possesses each phase of the U, the V that detect three-phase alternating-current motor 5, W, and the position detector 11 that detects the rotor-position of three-phase alternating-current motor 5, carry out the feedback signal that time diffusion obtains spinner velocity with the output of 12 pairs of position detectors 11 of differentiator.To given electromotor velocity instruction, calculate from the feedback speed signal of differentiator 12 and the velocity deviation between the speed command by adder 13a, current command generator 14 makes the two-phase current command value by vector control according to from the velocity deviation of adder 13a and current rate signal.
On the other hand, the electric current of each phase of the three-phase alternating-current motor 5 that current detector 10a, 10b, 10c detect is transformed to digital signal through A/ D converter 15a, 15b, 15c, the output of A/D converter 15b, 15c be multiply by correction factor Kv, Kw with corrected Calculation device 21a, 21b, be used to carry out vector control, with the output of A/D converter 15a and via the A/D converter 15b of corrected Calculation device 21a, 21b, the output of 15c, make three-phase/two phase inversion with coordinate converter 16, transform on the control reference axis of signal of position detector 11.
Adder 13b, 13c calculate the two-phase current instruction of current command generator 14 outputs and from the deviation between the two-phase current feedback signal of coordinate converter 16, current controller 17a, 17b amplify this deviation and output.Then, the output of this current controller 17a, 17b is made two-phase/three phase inversion by coordinate converter 18, makes the three-phase voltage command signal.
In addition, possess current sensor gain coefficient calculator 22 and signaling switch 23, the former is according to carrying out mensuration, the calculating of correction factor Kv, the Kw of corrected Calculation device 21a, 21b from the current sensor gain coefficient revision directive of outside, and the latter will switch to the mensuration of correction factor of current detecting gain of current sensor gain coefficient calculator 22 outputs to the voltage instruction with pwm signal generator 19 with value according to the current sensor gain coefficient revision directive from the outside.In common running action, do not set the revision directive of current sensor gain coefficient, so signaling switch 23 will export pwm signal generator 19 from the voltage instruction of coordinate converter 18 to, carry out the vector control of three-phase alternating-current motor 5.
Voltage instruction via signaling switch 23 is input to pwm signal generator 19, be transformed into switching signal, and it is inputed to gate drive circuit 20 make drive signal, be used for the power semiconductor component in the duty ratio break-make switching DC-to-AC converter 4 of regulation, thus, export desired three-phase ac power to three-phase alternating-current motor 5.In above formation, the control device that chain-dotted line surrounds part often uses digital circuit that (all not shown) such as CPU, memory, logical circuits constitute and the software that has loaded this circuit to realize.
As adopt the control device of the three-phase alternating-current motor shown in Figure 1 of above-mentioned formation, then in each circuitry phase detected value of three-phase alternating-current motor with 1 phase (for example U phase) as the benchmark phase, only in reaching the winding of 1 phase in addition mutually, this benchmark flows through the direct current of regulation, the current detecting gain of obtaining the benchmark phase from each current detection value at this moment and other 1 mutually the ratio of current detecting gain.And, only make described benchmark and 1 mutually lead again flow through the direct current of regulation, obtain the current detecting gain of benchmark phase and 1 mutually the ratio of current detecting gain again from current detection value at this moment.When motor operation, than the correction factor of calculating current detection value, be multiplied by this coefficient and come correcting current to detect the imbalance of gain with the conversion gain of trying to achieve.
That is to say, in control device shown in Figure 1, increase:, carry out corrected Calculation device 21a, the 21b of current detection value correction the output that correction factor Kv, Kw multiply by A/D converter 15b, 15c; The mensuration of correction factor Kv, Kw, the current sensor gain coefficient calculator 22 of calculating are carried out in the current sensor gain coefficient revision directive that the correction factor that utilizes indicator current to detect gain is measured; And utilize current sensor gain coefficient instruction will switch to the signaling switch 23 of mensuration usefulness value of correction factor of the current detecting gain of current sensor gain coefficient calculator 22 outputs to voltage instruction with pwm signal generator 19.
In common running action, do not set the revision directive of current sensor gain coefficient, so signaling switch 23 exports the voltage instruction of coordinate converter 18 outputs to pwm signal generator 19, carry out the vector control of threephase motor 5.At this moment, with corrected Calculation device 21a, 21b correction factor Kv, Kw be multiply by the output of A/D converter 15b, 15c in the control device shown in Figure 1, correction is carried out vector control with respect to the imbalance of the gain of the current detecting of the V of benchmark phase U phase, W phase and A/D conversion with revised current value.In the common running action of not setting the revision directive of current sensor gain coefficient, it is certain that correction factor Kv, kw keep.By above-mentioned revised current detection value is made value after three-phase/two phase inversion by coordinate converter 16, come Control current as feedback signal, just can eliminate the poor of conversion gain that the current detector of each phase produces, not have the imbalance of electric current, can reduce torque pulsation.
Action when the correction factor that carries out the current detecting gain is measured below is described.
At first discuss and exchange motor 5 is crossed the relation of digital signal value Xu, Xv, Xw and current transformation gain A v, the Aw of the electric current of each phase at a certain transient flow.Neutral point not with general three-phase alternating-current motor that the outside connects in each electric current I u, Iv, Iw mutually the relation of formula (1) is arranged.
Iu+Iv+Iw=0 ……(1)
Current value to each phase carries out digital conversion, just produce above-mentioned like that because of the error that detects, conversion causes, for example the digital conversion gain with the U phase is a benchmark, if with respect to Kv, the Iw of the correction factor of the current transformation gain of the V of U phase, W phase, the relation of formula (2) is arranged between the signal value after the digital conversion then
Xu+Kv·Xv+Kw·Xw=0 ……(2)
Thus, certain has the relation (1 expression is 1 signal regularly, the signal of 2 expression timings 2) as shown in the formula (3-1), (3-2) in a flash between the digital signal value of each phase current of (regularly 1) and another moment (regularly 2).
Xu1+Kv·Xv1+Kw·Xw1=0 ……(3-1)
Xu2+Kv·Xv2+Kw·Xw2=0 ……(3-2)
Because of unknown number is 2 of Kv, Kw, connection is separated two formulas and can be tried to achieve Kv, Kw among following formula (3-1), (3-2).At this moment, there is no need during owing to mensuration to make the electric current of a certain phase is zero, so there is no need the voltage instruction of pwm signal generator 19 is done inching.
Below explanation is asked the correction factor Kv of current transformation gain, the concrete grammar of Kw from formula (3-1), (3-2).
Arrangement formula (3-1), (3-2) and with matrix notation suc as formula (4).
[mathematical expression 1]
Deformation type (4) gets formula (5)
As with formula (5), then can (Xu1, Xv1 be Xw1) with (Xu2, Xv2 Xw2) try to achieve correction factor Kv, the Kw of current transformation gain from the digital signal value of each phase current of 2 groups of 2 timings.The contrary determinant on formula (5) the right is specifically represented by formula (6).
[mathematical expression 3]
Here, if the error that size is certain because mensuration noise etc. is sneaked under the situation of each digital signal value, from asking the computational accuracy of Kv, Kw to have in mind with formula (5), then as can be known when the electric current that flows through the U phase is identical, the denominator on formula (6) the right influence of mistake more is just more little.This show use electric current flow through U and V mutually between and state (regularly 1) that W flows through electric current mutually hardly and electric current flow through between U and the W phase and the V phase flows through under the situation of 2 groups of digital signal values of state (timing 2) of electric current hardly, the correction factor Kv that above-mentioned current transformation gains, the computational accuracy of Kw uprise.
The action of the current sensor gain coefficient calculator 22 in the controller for ac motor of the flowchart text example 1 of the present invention that following reference is shown in Figure 2 when the correction factor of asking the current transformation gain.
At first, at first step 40, the input of 22 pairs of pwm signal generators 19 of current sensor gain coefficient calculator provides voltage setting value, makes the direct current of showing regulation greatly flow through U phase and V winding mutually, does not almost have electric current to flow through the W phase winding simultaneously.For example, give identical mutually to U and V and the voltage instruction of opposite in sign is given and 0 voltage instruction mutually to W with size.Then in the 2nd step 41, current detector 10a, 10b, 10c detect and flow through U phase, V phase, the W electric current of each winding mutually, A/ D converter 15a, 15b, 15c carry out digital conversion to it, and its digital signal value is stored as Xu1 (U phase), Xv1 (V phase), Xw1 (W phase) respectively.
Then, in the 3rd step 42, current U is made with the winding of W phase flow through the certain direct current identical with the 1st step.Then in the 4th step 43, with the 2nd step similarly detect flow through U mutually, V phase, the W electric current of each winding mutually, carry out digital conversion, its digital signal value is stored as Xu2 (U phase), Xv2 (V phase), Xw2 (W phase) respectively.
At last, calculating in the 5th step 44 of correction factor, obtain V phase and correction factor Kv, the Kw of W respectively with respect to the U phase according to above-mentioned formula (5) with each digital signal value Xu1, Xv1, Xw1 and Xu2, Xv2, each value of Xw2.
After obtaining Kv, Kw by above action, the coefficient update that will be set in corrected Calculation device 21a, 21b is the new coefficient that calculates, and finishes the mensuration action of the correction factor of current detecting gain.
When using current detector, make before using and flow through the alternating current of decay in time, remove the demagnetization action of the magnetic hysteresis of current detector internal magnetic circuit, and then the detection output under electric current 0 state after the storage demagnetization action, as the offset of current detecting, generally is to deduct value behind the offset the detected value during from actual measurement as current detection value with this value.For these actions, though record in the example of the present invention, by implementing these actions, the precision that can improve the correction factor of current detecting and current detecting gain among the present invention is self-evident before the correction factor of measuring the current detecting gain.And handling current detection value by suitable low pass filter, can to reduce The noise be self-evident.
Again, mainly be to make electric current flow through two-phase in the three-phase of alternating current motor when asking the correction factor of current transformation gain in the above-mentioned example, yet owing to formula (5) is all set up regardless of the size of each phase current, so also can try to achieve the correction factor that current transformation gains under the "on" position arbitrarily certainly.Again, in above-mentioned example, measure current detection value, try to achieve the correction factor of current transformation gain, yet the electric current that flows through needs not to be direct current, uses measuring clog-free low-frequency ac electric current also harmless with flowing through direct current.Again, be to make to carry out the correction factor that the current transformation gain is once tried to achieve in processing shown in Figure 2 in the above-mentioned example, if yet repeatedly carry out the action of Fig. 2, calculate the mean value of correction factor of a plurality of current transformations gain of gained, the correction factor that then can obtain more current with high accuracy conversion gain is self-evident.
Thereby, according to above-mentioned example 1, because current sensor gain coefficient calculator 22 is when asking the correction factor of a certain phase, except that this reaches the current detection value of benchmark phase mutually, also the current detection value with another phase calculates, there is no need when therefore correction factor is measured to make the electric current of arbitrary phase is zero, there is no need the inching voltage instruction.
Again, illustrated with position detector vector control AC motor in the above-mentioned example, carried out the situation of speed control, yet for the vector control of the induction motor of speed detector and without the no sensor vector control of speed control position detector etc., same effect is also arranged certainly, and to speed control from outer control mode (Position Control, torque control etc.) also certainly effectively.Again, scope of the present invention is not limited to carry out the vector control mode of current feedback, but applicable to calculating the control mode of voltage instruction with detected electric current, and have same effect.
Example 2
Below explanation utilizes the action of the example 2 of control device algorithm, of the present invention alternating current motor different with above-mentioned example 1.Fig. 3 illustrates the flow chart of the action of the current sensor gain coefficient calculator 22 when asking the correction factor of current transformation gain in the control device of alternating current motor of example 2 of the present invention.
In the example 2, the action of step 41~43 is also identical with example 1, and digital signal value Xu1, Xv1, Xw1 and Xu2, Xv2, the Xw2 of 2 times amperometric determination are stored.In the 5th step 45, obtain V phase and correction factor Kv, the Kw of W respectively, but this algorithm is different with example 1 with respect to the U phase.
In the 5th step 45 in example 2, utilize repeated calculation to obtain correction factor Kv, Kw.At first, in the step 46 as calculating initial value configuration part, the counter n that sets repeated calculation is 0, and initial value Kv (o), the Kw (o) of correction factor Kv (n), the Kw (n) of set-up and calculated process are 0 simultaneously.
Then, carry out the calculating of correction factor as the step 47 of calculating part.At first, calculate the correction factor Kv (n) of V phase, with last time calculate the Kw (n) that tries to achieve, also the digital signal value Xw1 with the W phase calculates.When for the first time being n=0 owing to there is not last time calculated value, so be 1 at the initial value Kw (o) that calculates initial value configuration part 46 setting correction factor Kw (n).Then similarly calculate the correction factor Kw (n) of W phase, at this moment with the adjacent Kv (n) that tries to achieve before it, also the digital signal value Xv2 with the V phase calculates.
As the step 48 of control part repeatedly, calculate last time poor Kv (n+1)-Kv (n), Kw (the n+1)-Kw (n) with the correction factor of current calculating, then make calculating part 47 actions as this difference once more greater than the appearance value e that permitted of regulation, as less than being permitted just end calculating of appearance value e.Correction factor Kv (n+1), the Kw (n+1) that will finish in step 49 calculating as coefficient settings portion preserved as last correction factor Kv, Kw at last.
Thereby, in the calculating of this example 2,, therefore have the intuitively intelligible feature of computation structure, and correction factor Kv, Kw just approached originally at 1 o'clock, because convergence is fast, so be expected to reduce amount of calculation owing to do not carry out contrary determinant and do not calculate with calculating.
Again, above-mentioned situation finishes to calculate with correction factor Kv, Kw convergence state in the scope of being permitted appearance value e of regulation, but requiring calculation times repeatedly for the claimed accuracy that obtains correction factor Kv, Kw is predefined occasion, also can simultaneously increase counter n, one side makes n0 time the stipulated number n0 that only stipulates as step 47 action of calculating part repeatedly, can make the algorithm simplification.
Example 3
The method that DC-to-AC converter is carried out the action different with common running when the correction factor of asking the current transformation gain more than has been described in the explanation, yet inverter also can similarly be tried to achieve the correction factor of current transformation gain when turning round usually.Fig. 4 illustrates in the common synchronous motor control relation under d shaft current o control situation commonly used, rotor electrical angle and each phase current, as seen from the figure, regularly near 1 near (60 ° of the electrical angles) U flow through electric current mutually with V and W does not almost have electric current mutually, near (120 ° of the electrical angles) U flows through electric current mutually with W and the V phase does not almost have electric current near timing 2.As these are regularly carried out amperometric determination, then the inverter in turning round usually also may be tried to achieve the correction factor of current transformation gain.
Fig. 5 is the formation block diagram of the controller for ac motor of example 3 of the present invention.The digital signal value that current sensor gain corrected Calculation portion 22 obtains according to A/ D converter 15a, 15b, 15c in the example 3 shown in Figure 5 and the rotor-position signal of position detector 11 are calculated correction factor Kv, Kw.
Fig. 6 illustrates the flow chart of the action of current sensor gain corrected Calculation portion 22.The following action that example 3 of the present invention is described according to this figure.There is the part of duplicate numbers to have same function with Fig. 1, Fig. 2 among two figure.
In the example 3 of the present invention, inverter continues common running when asking the correction factor of current transformation gain.When asking the correction factor of current transformation gain, current sensor gain corrected Calculation portion 22 at first monitors rotor-position signal in the 1st step 50, wait for regularly 1 the state that arrives, when rotor arrives when being equivalent to regularly 1 electrical angle, detect each phase current in the 2nd step 41, and store it.
Then, wait for regularly 2 the state that arrives, when rotor arrival is equivalent to the electrical angle of timing 2, detects each phase current and store it in the 4th step 43 in the 3rd step 51.In the end the 5th step is calculated correction factor Kv, Kw.Calculating the finish time, the correction factor that is set in error correction calculator 21a, 21b is updated to the correction factor of new calculating.
More than in the explanation, get the timing that detects each phase current and be 60 ° of electrical angles with 120 ° two, yet same timing also can appear at 240 ° with 300 °, and the latter's timing effect is also identical.Use formula (5) is calculated correction factor Kv, Kw, also sets up beyond above-mentioned specific timing from the principle, therefore under the not too important situation of computational accuracy, also can carry out current detecting with the timing beyond above-mentioned.
Again, calculating according to the gain of the current transformation in the running of example 3 correction factor, the amplitude of each phase current is big more, and the frequency of electric current is low more, the current value that is used to calculate is just big more and stable, thereby it is self-evident improving the computational accuracy this point, therefore do not calculate, upgrade the current transformation gain correction factor irrelevant with operating condition, but at above-mentioned big electric current, when driving, low frequency carries out the calculating of correction factor, upgrade, when not having such operating condition, make the calculating that stops correction factor, method for updating can be carried out the renewal of suitable current transformation gain correction factor.
Again, in the above-mentioned example 3, current sensor gain corrected Calculation portion monitors rotor-position signal and judges the timing of amperometric determination, yet replaces rotor-position to judge that mensuration is regularly also harmless naturally with the Control Shaft phase place of vector control, can obtain same effect.
Thereby, according to example 3, since make current sensor gain coefficient calculator 22 according to the control electrical angle phase place of the regulation of DC-to-AC converter carry out correction factor mensuration, calculate, upgrade, make when the correction factor of asking certain 1 phase, except that reaching the current detection value of benchmark phase mutually, this also calculates, even therefore also can obtain the correction factor of current transformation gain the inverter in the common running with other current detection value of 1 phase.