JP4529488B2 - Phase voltage command value correction method and motor control device using this phase voltage command value correction method - Google Patents

Description

  The present invention relates to a motor control device that converts a DC power source into AC power having a required frequency and voltage to control a motor at a variable speed, and more particularly to a motor control device that includes a correction circuit that corrects a phase voltage command value to be compared with a carrier wave. The present invention also relates to a phase voltage command correction method for correcting a phase voltage command value to be compared with a carrier wave in a control unit of a motor control device.

  A motor control device that controls a motor at a variable speed is generally composed of a converter unit that converts AC power, which is a commercial power source, into DC power, and a bridge configuration of a semiconductor switching element such as a transistor. The phase voltage command value is obtained from the inverter unit that converts to the AC power of the motor, various commands such as operation command and speed command, and various setting conditions such as acceleration / deceleration time and voltage / frequency pattern. In comparison, the control unit includes a control unit that calculates and outputs a pulse width modulation signal as a switching signal for on / off control of the semiconductor switching element that constitutes the inverter unit. Here, when the phase voltage command value exceeds the peak value of the carrier wave, the switching is fixed (saturated state), so the line voltage output from the inverter section has a distorted waveform. End up. Due to the distortion of the line voltage, phenomena such as a decrease in output current (output torque) and hunting of the output current occur. Therefore, it is necessary for the control unit to correct the phase voltage command value in consideration of the saturation state.

Japanese Patent Application Laid-Open No. H10-228688 discloses a technique in which distortion of the line voltage due to output voltage saturation is eliminated even when the AC voltage command value for controlling the voltage source inverter exceeds the peak value of the carrier wave. In Patent Literature 1, when the output voltage of the inverter is fixed to the voltage of the DC power source as a result of the one-phase AC voltage command value exceeding the peak value of the carrier wave, the output voltage of the inverter and the AC voltage command value are A control device for a voltage source inverter having a saturation correction circuit for adding a difference to another two-phase AC voltage command value is described.
Moreover, even if one phase voltage is saturated, there is one disclosed in Patent Document 2 as a multiphase inverter device that can output a voltage with less distortion as a line voltage. Patent Document 2 uses a carrier signal of a predetermined period and a control voltage signal of at least two phases as input signals to generate a switching control signal for a PWM inverter device over multiple phases, and controls the output voltage of the PWM inverter device In this case, a positive / negative reference value that is substantially equal to the amplitude of the carrier signal is provided, and when the control voltage signal of one phase of the control voltage signal exceeds the reference value over the positive and negative values, the excess DC component is added to the carrier signal. An adder that outputs a corrected carrier signal is provided, and the control voltage signal of one phase and the control voltage signal of the other phase are compared with the corrected carrier signal and created as a switching control signal of the PWM inverter device.

JP-A-7-143760 JP-A-6-30588

  In Patent Document 1, the difference between the inverter output voltage and the AC voltage command value when the output voltage of the inverter is fixed to the voltage of the DC power source as a result of the AC voltage command value of one phase exceeding the peak value of the carrier wave. Is added to the other two-phase AC voltage command value, so the other two-phase output line voltage becomes equal to the AC voltage command value, and good control performance is maintained by the distortion-free output line voltage. In addition, since the carrier signal for generating the switching control signal of the multi-phase inverter device is shifted by a necessary amount in real time as needed, the above-mentioned Patent Document 2 still has the possibility that one phase voltage is likely to be saturated. There is an effect that the output voltage (line voltage) of the inverter device with less distortion can be obtained by extraly drawing out the phase voltage of the other phase having a margin. However, there is no description about the effect on the phase that does not cause phase voltage saturation due to the neutral point potential transfer of the saturated phase voltage command, and the case where two or more phases are saturated at the same time. When point potential movement is performed, phenomena such as a decrease in output current (output torque) and output current hunting still cannot be solved, and it is difficult to drive at constant speed, and the speed reaches the target value in the low output torque region. There was a problem of not reaching.

  The present invention has been made to solve the above-described problems. The neutral phase potential shift of the saturated phase voltage command value affects the phase in which phase voltage saturation has not occurred. Two or more phases are saturated simultaneously. A phase voltage command value correction method that can reduce line voltage distortion by performing phase voltage command value correction that takes into account the saturation state of the phase voltage command value, etc., and this phase voltage command value correction An object of the present invention is to obtain a motor control device using the method.

  The motor control device according to the present invention has a bridge configuration of semiconductor switching elements, and converts an inverter unit that converts DC power into AC power having a predetermined frequency and voltage, various commands such as operation commands and speed commands, and acceleration / deceleration. A phase voltage command value is obtained from various setting conditions such as time, phase voltage command value / frequency pattern, etc., and the phase voltage command value is compared with a carrier wave to control on / off of the semiconductor switching elements constituting the inverter unit. And a control unit that calculates and outputs a pulse width modulation signal as a switching signal. The control unit is configured such that two of the three-phase voltage command values are saturated, or three-phase When one phase of the voltage command value is saturated and the difference between the maximum value and the minimum value of the three-phase phase voltage command values is larger than the DC voltage value of the DC power, Saturated amount of moving the point potential saturated two-phase is was a correction circuit for correcting to be equal.

  In the present invention, when two of the three-phase voltage command values are saturated, or one of the three-phase voltage command values is saturated, and the maximum and minimum values of the three-phase voltage command values When the difference between the two values is larger than the DC voltage value of the DC power, the saturated neutral point potential is moved and corrected so that the saturation amount of the saturated two phases becomes equal. A voltage can be obtained.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a motor control apparatus according to Embodiment 1 of the present invention.
In FIG. 1, a commercial power source 1 is converted into DC power by a converter unit 2, and this DC voltage is smoothed by a capacitor 3. The smoothed DC voltage at both ends of the capacitor 3 becomes the DC bus voltage Vdc. The inverter unit 4 has a bridge configuration of semiconductor switching elements such as transistors, converts DC power into AC power having a predetermined frequency and a predetermined voltage, and controls the motor 5 at a variable speed. Further, the control unit 6 obtains a phase voltage command value from various commands such as an operation command and a speed command and various setting conditions such as acceleration / deceleration time and voltage / frequency pattern, and compares the phase voltage command value with a carrier wave, It calculates and outputs a pulse width modulation signal as a switching signal for controlling on / off of the semiconductor switching elements constituting the inverter unit 4.
Further, in the control unit 6, the phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ) are calculated from various commands such as operation commands and speed commands and various setting conditions such as acceleration / deceleration time and voltage / frequency pattern by the arithmetic circuit 7. Output. The correction circuit 8 corrects the phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ) and outputs corrected phase voltage command values (Vu ^ref cmd, Vv ^ref cmd, Vw ^ref cmd). The modulation circuit 9 compares the phase voltage command values (Vu ^ref cmd, Vv ^ref cmd, Vw ^ref cmd) after correction and the carrier wave output from the carrier wave generator 10 to compare the semiconductor switching elements constituting the inverter unit 4 A pulse width modulation signal (Su, Sv, Sw) as a switching signal for ON / OFF control of the signal is calculated and output.

2A and 2B are diagrams showing the waveform of the phase voltage command value and the waveform of the line voltage. FIG. 2A shows the waveform of the phase voltage command value, and FIG. 2B shows the waveform of the line voltage. When the DC bus voltage is Vdc, the voltage that can be output by the inverter unit 4 is Vdc / 2, and the phase voltage command values Vu ^ref , Vv ^ref , Vw ^ref are clamped at the limit value Vlim (± Vdc / 2).
In FIG. 2A, when the phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ) indicated by the broken lines exceed the limit value ± Vdc / 2, the voltage saturation occurs, so that the output is clamped and actually output. is the phase voltage command values ^{Vu ref ', Vv ref',} Vw ref ' has a waveform indicated by the solid line, the command value as the waveform of the line voltage shown in FIG. 2 (b) a waveform indicated by a broken line However, the waveform that is actually output is such that the utilization factor of the line voltage decreases and the line voltage waveform is distorted, as in the waveform shown by the solid line.

FIG. 3 is a diagram showing the configuration of the correction circuit 8 in the motor control apparatus according to Embodiment 1 of the present invention. In FIG. 3, the correction amount calculation circuit 11 has a limit value ± Vdc / 2 based on the phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ) output from the calculation circuit 7 and the limiter 12 (12u, 12v, 12w). The clamped phase voltage command value (Vu ^ref ′, Vv ^ref ′, Vw ^ref ′) is input, and the correction amount δV and the correction amount K · δV are calculated. Further, the calculator 13 (13u, 13v, 13w) subtracts the correction amount K · δV from the phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ) to correct the corrected phase voltage command values (Vu ^ref cmd, Vv ^ref cmd, Vw ^ref cmd) is obtained and output to the modulation circuit 9.

FIG. 4 is a diagram for explaining correction amount calculation processing in the correction amount calculation circuit 11 in the motor control apparatus according to Embodiment 1 of the present invention. FIG. 4A is an explanatory diagram for correcting the saturated two-phase phase voltage command values so that the saturation amounts are equal, and FIG. 4B is a correction so that the ratio of the phase voltage command values is the same as before the correction. It is explanatory drawing to do.
In FIG. 4A, white circles indicate phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ) before correction, black circles indicate phase voltage command values (Vu ^ref cmd, Vv ^ref cmd, Vw ^ref cmd) after correction, one point chain line is a virtual neutral point potential. Also, Vmax is the phase voltage command values ^{(Vu ref, Vv ref, Vw} ref) the maximum value of, Vmin is the phase voltage command values ^{(Vu ref, Vv ref, Vw} ref) the minimum value of, Vmax 'will correct the maximum value Vmax The phase voltage command value corrected by the amount δV, Vmin ′ is the phase voltage command value corrected by the minimum value Vmin by the correction amount δV, ΔVa is the saturation amount after correction on the Vmax side, and ΔVb is the saturation amount after correction on the Vmin side. is there. The limit value of the phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ) is ± Vdc / 2. Further, a and b are ratios of phase voltage command values before correction, and a1 and b1 are ratios of phase voltage command values after correction with a correction amount δV.
In FIG. 4B, the white circles are the phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ) before correction, and the black circles are the phase voltage command values (Vu ^ref cmd, Vv ^ref cmd, Vw ^ref cmd) after correction. ), one point chain line is a virtual neutral point potential. a2 and b2 are ratios of phase voltage command values after correction with a correction amount K · δV (where K is a coefficient that can be varied according to the purpose of the system).

The correction amount calculation process will be described with reference to FIG. If the phase voltage command value of two phases out of the three phase voltage command values (indicated by white circles in the figure) exceeds the limit value Vlim (= ± Vdc / 2), the phase voltage of the saturated two phases The correction amount δV is calculated so that the saturation values of the command values are equal. In FIG. 4 (a),
ΔVa = Vmax−Vlim−δV (1)
ΔVb = Vmin−Vlim + δV (2)
Here, assuming that ΔVa = ΔVb, the correction amount δV can be obtained by the following equation (3) from the equations (1) and (2).
Correction amount δV = {Vmax−Vlim + Vmin − (− Vlim)} / 2
= {Vmax + Vmin} / 2 (3)
Where Vmax = max {Vu ^ref , Vv ^ref , Vw ^ref },
Vmin = min {Vu ^ref , Vv ^ref , Vw ^ref }

Further, even after the phase voltage command value is corrected by the correction amount δV obtained by the equation (3), the maximum value Vmax ′ and the minimum value Vmin ′ of the phase voltage command value after correcting two saturated phases are the limit value Vlim. It exceeds (= ± Vdc / 2) and is clamped at the limit value Vlim. For this purpose, the ratio of the phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ) output from the arithmetic circuit 7 to the ratio of the corrected phase voltage command values (Vu ^ref cmd, Vv ^ref cmd, Vw ^ref cmd) Will change (a: b ≠ a1: b1), which increases the distortion factor of the line voltage.

In FIG. 4B, the ratio of the phase voltage command values (Vu ^ref cmd, Vv ^ref cmd, Vw ^ref cmd) after correction is the same as the ratio of the phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ) before correction. In this example (a: b = a2: b2), a new correction amount K · δV is obtained by multiplying the correction amount δV obtained by the equation (3) by a coefficient K. The coefficient K in this case is obtained by the following equation (4).
Coefficient K = Vdc / Vmax-min (4)
Here, Vdc is a DC bus voltage, and Vmax-min is a voltage difference (Vmax-min = Vmax−Vmin) between a maximum value and a minimum value of phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ).

At the time of two-phase saturation, the ratio of the phase voltage command after correction is made to be the same as the ratio of the phase voltage commands (Vu ^ref , Vv ^ref , Vw ^ref ) before correction (a: b = a2: b2). As a result, distortion of the line voltage can be reduced.

In the above ^description , the phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ) (indicated by white circles in the figure) output from the arithmetic circuit 7 are corrected with the correction amount δV or the correction amount K · δV, Although an example in which the phase voltage command values (Vu ^ref cmd, Vv ^ref cmd, Vw ^ref cmd) (shown by black circles in the figure) are described, the virtual neutral point potential is moved by the correction amount δV or the correction amount K · δV. You may do it.

FIG. 5 is a diagram for explaining the correction amount calculation processing at the time of one-phase saturation in the correction amount calculation circuit 11 in the motor control apparatus according to Embodiment 1 of the present invention. 5 (a) and 5 (b), when the saturation amount is used as the correction amount, FIG. 5 (c) is a case where the correction amount is calculated so that the saturation amounts of the two-phase phase voltage command values are equal. It is.
In FIG. 5, white circles are phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ) before correction, black circles are phase voltage command values (Vu ^ref cmd, Vv ^ref cmd, Vw ^ref cmd) after correction, and Vmax is a phase. The maximum voltage command value, Vmin, is the minimum phase voltage command value. Vmax-min is a voltage difference (Vmax-min = Vmax−Vmin) between the maximum value and the minimum value of the phase voltage command value. Further, a and b are phase voltage command ratios before correction, and a3 and b3 are phase voltage command ratios after correction.

When Vmax-min ≦ Vdc at the time of one-phase saturation, as shown in FIG. 5A, the saturation amount is used as the correction amount, and the correction amount δV is calculated by the following equation (5).
Correction amount δV = {Vu ^ref , Vv ^ref , Vw ^ref }
-{Vu ^ref ', Vv ^ref ', Vw ^ref '} (5)
Here, Vu ^ref , Vv ^ref and Vw ^ref are phase voltage command values, and Vu ^ref ′, Vv ^ref ′ and Vw ^ref ′ are phase voltage command values clamped by a limiter.

When Vmax-min> Vdc when one phase is saturated, if the saturation amount is used as the correction amount, the non-saturated phase has the limit value Vlim (= ± Vdc / 2) as shown in FIG. It will be over. Therefore, when Vmax-min> Vdc at the time of one-phase saturation, the saturation amount of the saturated two-phase phase voltage command value becomes equal using the above equation (3) at the time of two-phase saturation. Thus, the correction amount δV is calculated.
Correction amount δV = {Vmax + Vmin} / 2 (3)
Where Vmax = max {Vu ^ref , Vv ^ref , Vw ^ref },
Vmin = min {Vu ^ref , Vv ^ref , Vw ^ref }.

Furthermore, the ratio K of the phase voltage command values after correction is calculated using the coefficient K obtained by the above-described equation (4) at the time of two-phase saturation, and the phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref before correction). ) To obtain a new correction amount K · δV by multiplying the correction amount δV obtained by the equation (3) by the coefficient K.
When Vmax-min> Vdc at the time of one-phase saturation, the ratio of the phase voltage command values after correction is made to be the same as the ratio of the phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ) before correction. By doing so, the distortion of the line voltage can be reduced.

  FIG. 6 is a flowchart showing a correction process in the correction circuit 8 and the correction amount calculation circuit 11 in the motor control apparatus according to the first embodiment of the present invention.

The correction processing of the correction circuit 8 and the correction amount calculation circuit 11 will be described with reference to FIGS.
In step S1, the correction circuit 8 and the correction amount calculation circuit 11 receive the phase voltage command values (Vu ^ref , Vv ^ref , Vw ^ref ) output from the calculation circuit 7. In step S2, the correction amount calculation circuit 11 checks whether there is a phase that is voltage saturated with the three-phase phase voltage command value. If there is no voltage saturation, the correction amount δV = 0 is set in step S3.

When voltage saturation is detected in step S2, it is subsequently checked in step S4 whether only one phase is saturated (single-phase saturation) or two phases are saturated (two-phase saturation). .
If one-phase saturation is detected in step S4, then in step S5, the voltage difference (Vmax-min = Vmax-Vmin) between the maximum value and the minimum value of the phase voltage command value is compared with the DC bus voltage Vdc. To do. If it is determined in step S5 that Vmax-min ≦ Vdc, the process proceeds to step S6. If it is determined in step S5 that Vmax-min> Vdc, the process proceeds to step S7.
On the other hand, if two-phase saturation is detected in step S4, the process proceeds to step S7.

If it is determined in step S5 that Vmax-min ≦ Vdc, the correction amount δV is set to the above-described equation (5) in step S6 because the other phase voltage command value is not saturated even if the saturation amount is corrected. Calculate with.

If it is detected that two-phase saturation is detected in step S4, or if it is determined that Vmax-min> Vdc in step S5 in the case of one-phase saturation, the correction amount δV is calculated by the above equation (3) in step S7. To do.
Correction amount δV = {Vmax + Vmin} / 2 (3)
Where Vmax = max {Vu ^ref , Vv ^ref , Vw ^ref },
Vmin = min {Vu ^ref , Vv ^ref , Vw ^ref }.

  In step S8, the correction amount δV calculated in step S3, step S6 or step S7 is input and multiplied by a coefficient K according to the purpose of the system to obtain a final correction amount K · δV.

In step S9, the correction circuit 8 corrects the phase voltage commands Vu ^ref , Vv ^ref , Vw ^ref by the following equation (6) using the final correction amount K · δV calculated by the correction amount calculation circuit 11. If the phase voltage command value is Vuvw ^ref and the corrected phase voltage command value corrected using the final correction amount K · δV is Vuvw ^ref cmd,
Vuvw ^ref cmd = Vuvw ^ref −K · δV (6)

FIG. 7 shows a case where the phase voltage command values Vu ^ref , Vv ^ref , Vw ^ref are clamped by the limiter 12 (12u, 12v, 12w) with the limit value Vlim (± Vdc / 2), and the maximum amplitude value is obtained. It is a figure which shows the experimental result at the time of giving the phase voltage command value of 200V, (a) is a waveform of a phase voltage command value and a neutral point potential, (b) is a waveform of a line voltage, (c) is a line it is a diagram showing a F F T analysis between voltage. In FIG. 7 (a), (b) , that before the waveform shown by the broken line correction, waveform indicated by the solid line shows those after correction of clamping with the limit value Vlim. Further, one point chain line is a virtual neutral point potential.
As shown in FIG. 7 (c), the characteristics when the phase voltage command value is clamped by the limit value Vlim have a low harmonic component and a low distortion rate, but also a low fundamental wave component. It will be lower.

FIG. 8 shows a case where a process of correcting the saturation exceeding the limit value Vlim (± Vdc / 2) of the phase voltage command values Vu ^ref , Vv ^ref , Vw ^ref (for example, Patent Document 1 or Patent Document 2) is performed. FIG. 5 is a diagram showing experimental results when a phase voltage command value having a maximum amplitude value of 200 V is given, where (a) shows the waveform of the phase voltage command value and neutral point potential, and (b) shows the waveform of the line voltage. is a diagram showing a F F T analysis (c) is the line voltage. FIG. 8 (a), the (b), the waveform shown by broken lines those before correction, the waveform shown by the solid line shows those after the correction. Further, one point chain line is a virtual neutral point potential.
As shown in FIG. 8 (c), the characteristic when processing for correcting the saturation exceeding the limit value Vlim (± Vdc / 2) of the phase voltage command value has a large fundamental wave component, so the line voltage is effective. Although the value is high, the distortion rate becomes high because there are many harmonic components.

FIG. 9 shows a case where correction processing is performed in the correction circuit 8 and the correction amount calculation circuit 11 in the motor control device according to the first embodiment of the present invention, and an experiment when a phase voltage command having a maximum amplitude value of 200 V is given. shows the results, (a) shows the waveform of the phase voltage command value, (b) is a diagram showing the waveform of the line voltage, the F F T analysis (c) is the line voltage. FIG. 9 (a), the (b), the waveform shown by broken lines those before correction, the waveform shown by the solid line shows those after the correction. Further, one point chain line is a virtual neutral point potential.
As shown in FIG. 9C, the characteristic when the phase voltage command value is corrected according to the first embodiment described above is such that the harmonic component is suppressed while the fundamental component is kept at a high value. ing.

FIG. 10 is a graph comparing the corrected characteristics shown in FIGS. 7, 8, and 9. FIG. 10 (a) shows the distortion rate, and FIG. 10 (b) shows the line voltage effective value.
Type a is the characteristics when the phase voltage command value shown in FIG. 7 is clamped by the limit value Vlim, and type b is the saturation that exceeds the limit value Vlim (± Vdc / 2) of the phase voltage command value shown in FIG. The characteristic when the process of correcting the phase voltage is performed, and type c is the characteristic when the process of correcting the phase voltage command value is performed according to the first embodiment shown in FIG.

FIG. 11 is a graph comparing the corrected characteristics shown in FIGS. 7, 8 and 9 with the vertical axis representing the line voltage effective value and the horizontal axis representing the distortion rate. In FIG.
Region A is a region where the distortion rate is low and the line voltage effective value is high,
Region B is a region where the distortion rate is high and the line voltage effective value is high,
Region C has a low distortion rate and a low line voltage effective value,
Region D is a region with a high distortion rate and a low line voltage effective value.

It is desirable to control the distortion factor and effective value of the line voltage output from the motor control device so as to be in the region A. In the first embodiment described above, saturation of the saturated two-phase phase voltage command value is performed. Correct the ratio of phase voltage command values after correction as an example of correcting the amounts to be equal, and the final correction amount K · δV (where K is a coefficient that can be varied according to the purpose of the system) In order to make it the same as the ratio of the previous phase voltage command value, the coefficient K is expressed by equation (4) (coefficient K = Vdc / Vmax-min, where Vdc is the DC bus voltage and Vmax-min is the phase voltage command value. This is the voltage difference between the maximum and minimum values.)
By changing the coefficient K, characteristics according to the purpose of the system (distortion rate, ratio of effective value of line voltage) can be obtained.

  As described above, in the phase voltage command correction method of the present invention and the motor control device using this phase voltage command correction method, a line voltage having a small distortion rate and a high effective value can be obtained. It is suitable for applications that drive the motor stably in a constant output region.

It is a figure which shows the structure of the motor control apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the waveform of a phase voltage command, and the waveform of a line voltage. It is a figure which shows the structure of the correction circuit 8 in the motor control apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the correction amount calculation process in the correction amount calculation circuit 11 in the motor control apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the correction amount calculation process at the time of 1 phase saturation in the correction amount calculation circuit 11 in the motor control apparatus which concerns on Embodiment 1 of this invention. 3 is a flowchart showing correction processing in a correction circuit 8 and a correction amount calculation circuit 11 in the motor control apparatus according to Embodiment 1 of the present invention. The phase voltage command values Vu ^ref , Vv ^ref , Vw ^ref are clamped at the limit value Vlim (± Vdc / 2) by the limiter 12 (12u, 12v, 12w), and the phase voltage having the maximum amplitude value of 200V It is a figure which shows the experimental result at the time of giving command value. This is the case when processing for correcting the saturation exceeding the limit value Vlim (± Vdc / 2) of the phase voltage command values Vu ^ref , Vv ^ref , Vw ^ref (for example, Patent Document 1 or Patent Document 2) It is a figure which shows the experimental result at the time of giving the phase voltage command value of amplitude value 200V. The figure which shows the experimental result at the time of giving the correction process in the correction circuit 8 and the correction amount calculation circuit 11 in the motor control apparatus which concerns on Embodiment 1 of this invention, and giving the phase voltage command of the maximum amplitude value 200V It is. FIG. 10 is a diagram comparing the corrected characteristics shown in FIGS. 7, 8, and 9. It is the figure which compared the characteristic after correction | amendment shown in FIG.7, FIG8 and FIG.9 by making a vertical axis | shaft an effective voltage between lines and a horizontal axis | shaft into a distortion factor.

DESCRIPTION OF SYMBOLS 1 Commercial power supply, 2 Converter part, 3 Capacitor, 4 Inverter part, 5 Motor, 6 Control part, 7 Arithmetic circuit, 8 Correction circuit, 9 Modulation circuit, 10 Carrier wave generator, 11 Correction amount calculation circuit, 12 (12u, 12v 12w) Limiter, Vdc DC bus voltage, Vu ^ref , Vv ^ref , Vw ^ref phase voltage command value, Vu ^ref cmd, Vv ^ref cmd, Vw ^ref cmd Corrected phase voltage command value, Vlim limit value, Vu ^ref ', Vv ^ref ', Vw ^ref ' Clamped phase voltage command value, δV correction amount, K factor, Vu ^ref cmd, Vv ^ref cmd, Vw ^ref cmd Corrected phase voltage command value, Vmax maximum value of phase voltage command value, Vmin phase Minimum value of voltage command value, phase voltage command value obtained by correcting Vmax 'Vmax with correction amount δV, phase voltage command value obtained by correcting Vmin' Vmin with correction amount δV, ΔVa Saturation amount after correction, ΔVb Saturation amount after correction on Vmin side, a, b Ratio of phase voltage command value before correction, a1, b1 Ratio of phase voltage command value after correction with correction amount δV, a2, b2 correction Ratio of phase voltage command value after correction with quantity K · δV, a3, b3 Ratio of phase voltage command value after correction with correction quantity δV, Vmax-min Voltage between maximum value and minimum value of phase voltage command value Difference (Vmax−min = Vmax−Vmin), Su, Sv, Sw Pulse width modulation signal.

Claims (6)

It consists of a bridge structure of semiconductor switching elements, and converts inverter power that converts DC power into AC power with a predetermined frequency and voltage, and various commands such as operation commands and speed commands, acceleration / deceleration times, and voltage / frequency patterns. The phase voltage command value is obtained from the set conditions, the phase voltage command value is compared with the carrier wave, and a pulse width modulation signal is calculated and output as a switching signal for controlling on / off of the semiconductor switching element constituting the inverter unit. A motor control device including:
The controller is
If two of the three phase voltage command values are saturated from the limit value ,
Or, when one of the three phase voltage command values is saturated from the limit value , and the difference between the maximum and minimum values of the three phase voltage command values is larger than the DC bus voltage value of the DC power In addition,
Phase voltage command values of two phases in Rukoto moves the virtual neutral point potential without changing the ratio of the phase voltage command value and the corrected phase voltage command values before correction, the saturation amount from the limit value becomes equal A motor control device comprising a correction circuit that corrects the error as described above . It consists of a bridge structure of semiconductor switching elements, and converts inverter power that converts DC power into AC power with a predetermined frequency and voltage, and various commands such as operation commands and speed commands, acceleration / deceleration times, and voltage / frequency patterns. The phase voltage command value is obtained from the set conditions, the phase voltage command value is compared with the carrier wave, and a pulse width modulation signal is calculated and output as a switching signal for controlling on / off of the semiconductor switching element constituting the inverter unit. A motor control device including:
The controller is
If two of the three phase voltage command values are saturated from the limit value,
Or, when one of the three phase voltage command values is saturated from the limit value, and the difference between the maximum and minimum values of the three phase voltage command values is larger than the DC bus voltage value of the DC power In addition,
By obtaining 1/2 of the sum of the maximum value and minimum value of the three-phase phase voltage command values as a correction amount, and subtracting the correction amount from the three-phase phase voltage command value, the two-phase phase voltage command value becomes A motor control device comprising a correction circuit for correcting the saturation amount from the limit value to be equal. A phase voltage command value input step;
A step of confirming that there is no phase that is saturated in the input three-phase voltage command value;
When there is voltage saturation in the input phase voltage command value of the three phases, it is confirmed whether only one phase is saturated or two phases are saturated;
When there is no voltage saturation in the input three-phase phase voltage command value, the phase voltage command value is not corrected ,
When only one phase is saturated, correct the phase voltage command value of the saturated phase using the voltage saturation as the correction amount,
When the two phases are saturated, a step of correcting each of the three-phase phase voltage command values with a half of the sum of the maximum value and the minimum value of the phase voltage command values as a correction amount;
A phase voltage command correction method comprising: A phase voltage command value input step;
A step of confirming that there is no phase that is saturated in the input three-phase voltage command value;
When there is voltage saturation in the input phase voltage command value of the three phases, it is confirmed whether only one phase is saturated or two phases are saturated;
When only one phase is saturated, comparing the voltage difference between the maximum and minimum phase voltage command values with the DC bus voltage;
When there is no voltage saturation in the input three-phase phase voltage command value, the phase voltage command value is not corrected,
If only one phase is saturated, and when the difference between the maximum value and the minimum value of the phase voltage command value is less than the DC bus voltage, the phase voltage command phase saturated voltage saturates in the correction amount Correct the value,
Phase voltage command value when two phases are saturated or when only one phase is saturated and the voltage difference between the maximum and minimum phase voltage command values exceeds the DC bus voltage Correcting each of the three-phase voltage command values, with 1/2 of the sum of the maximum value and the minimum value as a correction amount,
A phase voltage command correction method comprising: The two-phase phase voltage command value is corrected so that the saturation amount from the limit value becomes equal without changing the ratio between the phase voltage command value before correction and the phase voltage command value after correction. The motor control device according to 2 The two-phase phase voltage command value is corrected so that the saturation amount from the limit value becomes equal without changing the ratio between the phase voltage command value before correction and the phase voltage command value after correction. 5. The phase voltage command correction method according to 3 or 4 .

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