JP2006166596A - Method of controlling power converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of controlling a small-sized and low-loss power converter which improves the output torque in a high-revolution range similar to the voltage change by a DC/DC converter, and does not require such large capacity as a coil, without being accompanied with such loss as a DC/DC converter for transmission of power between a power source and a motor. <P>SOLUTION: This is a method of controlling a power converter (40) which is connected with a plurality of DC power sources (10a and 10b) and generates drive voltage by generating and synthesizing pulses from each output voltage of these DC power sources and drives an AC motor (20). This includes an active voltage command generating step which generates an active voltage command being the motor voltage components of the same phase as a motor current, a reactive voltage command generating step of generating the reactive voltage command being the motor voltage component other than it, a voltage distributing step of distributing the above active voltage command and the above reactive voltage command into each voltage command each corresponding to the plurality of DC power sources, and a step of controlling the above power converter to generate each output voltage pulse, based on each voltage command stated above. According to this constitution, not only the distribution of the active power of the motor but also the distribution of reactive power can be controlled by distributing the active voltage and the reactive voltage of the motor voltage into voltage commands corresponding to the plurality of power sources, and generating voltage pulses thereby driving the motor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a method for controlling a power converter that drives an AC motor.

Conventionally, in an AC motor drive system, a configuration in which a DC voltage applied to an inverter is made variable by a DC / DC converter is known. For example, Japanese Patent Laid-Open No. 2003-116280 shown in FIG. It is disclosed in the configuration etc. In a drive system including a DC / DC converter, all the electric power that moves between the power source and the motor passes through the DC / DC converter, so that a loss occurs in the semiconductor switch and the coil. In a drive system including a DC / DC converter, all of the electric power that moves between the power source and the motor passes through the DC / DC converter, so that loss occurs in the semiconductor switch and the coil. The size increases.
JP 2003-116280 (paragraphs 0005-0006, FIG. 1)

  Therefore, the present invention aims to improve the output torque in the high rotation range as well as the variable voltage by the DC / DC converter, and the power transfer between the power source and the motor is accompanied by a loss like a DC / DC converter. In addition, the present invention provides a method for controlling a small-sized and low-loss power converter that does not require a large volume like a coil.

In order to solve the above-described problems, a method for controlling a power conversion device according to the first invention includes:
A method for controlling a power converter that is connected to a plurality of DC power supplies, generates a drive voltage by generating and synthesizing pulses from the output voltages of each of these DC power supplies, and drives an AC motor,
An effective voltage command value generation step for generating an effective voltage command value that is a motor voltage component in phase with the motor current;
A reactive voltage command value generation step for generating a reactive voltage command value that is other motor voltage component;
A voltage distribution step of distributing the effective voltage command value and the reactive voltage command value to each voltage command value corresponding to each of a plurality of DC power sources;
Controlling the power converter to generate each output voltage pulse based on each voltage command value; and
It is characterized by including.

The control method of the power converter according to the second invention is
The voltage command value generation step includes
Extracting the effective voltage command value from the motor voltage command value and the motor current phase,
The reactive voltage command value generation step includes
The reactive voltage command value is extracted from the motor voltage command value and the motor current phase.
It is characterized by that.

Furthermore, the control method of the power converter according to the third invention is
Furthermore, the step of obtaining the phase of the motor current from the phase of the command value of the motor current,
It is characterized by including.

Furthermore, the control method of the power conversion device according to the fourth invention is:
The reactive voltage command value generation step includes
Obtaining the reactive voltage command value by subtracting the effective voltage command value from the motor voltage command value;
It is characterized by that.

Furthermore, the control method of the power converter according to the fifth invention is:
And a step of calculating a dq-axis voltage command value for controlling the dq-axis current from the dq-axis current command value and the dq-axis current in the dq coordinate,
The effective voltage command value generation step includes
The effective voltage command value is extracted from the dq axis current command value and the dq axis voltage command value,
The reactive voltage command value generation step includes
The reactive voltage command is extracted from the dq axis current command value and the dq axis voltage command value.
It is characterized by that.

Furthermore, the control method of the power conversion device according to the sixth invention is:
The voltage distribution step comprises:
Multiplying the effective voltage command value by the active power distribution command value corresponding to each of the plurality of DC power sources to obtain a distributed effective voltage command;
Multiplying the reactive voltage command value corresponding to each of the plurality of DC power supplies by the reactive voltage command value to obtain a post-distributed reactive voltage command;
Obtaining each voltage command value corresponding to each of the plurality of DC power sources from the sum of the distributed effective voltage command value and the distributed reactive voltage command value, respectively.
It is characterized by that.

Furthermore, the control method of the power conversion device according to the seventh invention is:
Further, each voltage command value corresponding to each of the plurality of DC power supplies is obtained by normalizing each voltage command value by the voltage value of the DC power supply, and each voltage command Outputting each correction modulation rate command value by adding or subtracting an offset amount corresponding to the magnitude of the value;
It is characterized by including.

Furthermore, the control method of the power converter according to the eighth invention is:
Further, one of the plurality of DC power supplies is a capacitor, and the reactive voltage command value is a voltage command value corresponding to the power stored in the capacitor,
It is characterized by including.
As described above, the solving means of the present invention has been described as a method. However, the present invention can also be realized as a device, a program, and a storage medium recording the program, and the scope of the present invention. It should be understood that these are also included.

  According to the first aspect of the invention, the effective voltage and the invalid voltage of the motor voltage are distributed to voltage commands corresponding to a plurality of power supplies, and the motor is driven by generating voltage pulses. In addition, the distribution of reactive power can be controlled. This makes it possible to control a plurality of power sources as a power source that circulates only reactive power or a power source that supplies only active power. Since the power source that circulates only reactive power does not supply active power, its capacity may be small. By charging the voltage to a high voltage and using the voltage, the motor current is controlled so as to suppress the induced voltage of the motor, and the active power is supplied to the motor by driving from another power source. It is possible to improve the output torque of the motor in the high rotation range. In addition, in the prior art, boosting can be performed by using the reactive power that has passed through the switch group and returned to the power source, so that loss in the switch group can be reduced.

According to the second aspect of the invention, the effective voltage command and the reactive voltage command are extracted from the motor current phase and the motor voltage command value. Can be extracted. According to the third aspect of the invention, since the motor current phase is obtained from the motor current command value, the motor current phase can be obtained without being affected by noise or the like included in the detected value of the actual motor current. . According to the invention of claim 4,
Since the invalid voltage command is obtained by subtracting the valid voltage command value from the motor voltage command value, the calculation can be simplified. According to the fifth aspect of the invention, since the effective voltage command and the reactive voltage command are calculated in the dq coordinate, in the motor control system that performs the vector control in the dq coordinate, the calculation amount is the calculation amount in the three-phase AC Compared with less.

  According to the sixth aspect, by distributing the effective voltage and the reactive voltage according to the power source, it becomes possible to distribute the active power and reactive power supply sources for driving the motor according to the power source. Thus, the current control of the motor and the power control of the power source are performed at the same time, and the voltage control when the secondary battery is provided as the power source can be realized without newly providing another conversion device such as a DC / DC converter.

  In addition, according to the seventh invention, after normalizing the voltage command value with the voltage, the offset amount is obtained according to the voltage command value, and the process of adding or subtracting to the modulation factor command value is performed, thereby distributing the power. The ratio can be any value. According to the eighth aspect of the invention, since the capacitor is used as the power source, it is possible to reduce the size and cost. By setting the reactive voltage to a voltage command value corresponding to the power stored in the capacitor, it is possible to maintain the initially charged voltage without discharging the power from the capacitor. Using this capacitor voltage, the motor current is controlled so as to suppress the induced voltage of the motor, and the active power is supplied from another power source to the motor and driven, so that the output torque of the motor in the high rotation range can be reduced. It is possible to improve.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 3 shows a circuit diagram of a power converter suitable for use in the method for controlling a power converter according to the present invention. The negative electrode of the power supply 10a and the negative electrode of the power supply 10b are connected to the common negative electrode bus 15. A pair of semiconductor switches 107a, 108a, 109a and diodes 107b, 108b, 109b is connected between the common negative electrode bus 15 and each phase terminal of the motor 20 in the same manner as a generally known lower arm of an inverter. . The positive electrode bus 14 of the power supply 10a and each phase terminal of the motor 20 are connected by semiconductor switches 101a / 101b, 102a / 102b, 103a / 103b, respectively, capable of controlling bidirectional conduction. Further, semiconductor switches 104a / 104b, 105a / 105b, and 106a / 106b that can control bidirectional conduction are also connected between the positive electrode bus 16 of the power supply 10b and each phase terminal of the motor 20. A smoothing capacitor 12 is provided between the positive electrode bus 14 and the common negative electrode bus 15 of the power source 10a, and a smoothing capacitor 13 is also provided between the positive electrode bus 16 and the common negative electrode bus 15 of the power source 10b.

  The power converter 30 is a DC-AC power converter that generates a voltage to be applied to the motor based on the voltage of the above three potentials, the common negative electrode bus, the positive electrode bus of the power source 10a, and the positive electrode bus of the power source 10b. . The semiconductor switch provided in each phase of U phase (30U), V phase (30V), and W phase (30W) is a switch means that generates a voltage to be output to each phase of the AC motor. Alternatively, the necessary voltage is supplied to the motor by changing the ratio of the connection time.

  The configuration of the control device 40 will be described with reference to FIG. Reference numeral 41 denotes torque control means for calculating a d-axis current command value id * and a q-axis current command value iq * of the AC motor from a torque command given from the outside and the rotational speed of the motor. 42, current control for matching the dq-axis current command values id * and iq * and the dq-axis current values id and iq is performed, and the distribution target value of the active power supplied from the power sources 10 a and b (Rto_pa_a, rto_pa_b) and current / power control means for performing power control from reactive power distribution target values (rto_pr_a, rto_pr_b) circulating through the bus connected to the power supplies 10a and 10b.

Details of the current / power control means 42 will be described in detail with reference to FIG. The current control means 42a performs feedback control by PI control so that id and iq follow id * and iq *, respectively, and outputs dq axis voltage command values vd * and vq *. id and iq are obtained from the three-phase currents iu and iv by the three-phase / dq conversion means 48. The β angle calculation means 42b inputs id * and iq * and calculates the phase angle β * of the current command value based on the following formula (from the command value in the third invention, the dq axis in the fifth invention) From).
β * = tan ^-1 (-id / iq)
(However, if iq = 0, β * = π / 2)

なお、ベクトルの分解・合成によってdq軸の電圧成分を演算しているため、無効電圧成分については、次の式から演算することも可能である。

上の式を用いれば、v_r0を演算せずにvd_2*,vq_2*を求めることができるため、演算量を低減することが可能である（これは第４の発明に相当）。 The effective voltage components vd_1 * and vq_1 * and the reactive voltage components vd_2 * and vq_2 * are calculated using vd *, vq * and β *. As shown in the current / voltage vector diagram of FIG. 12, first, the voltage command values vd * and vq * are decomposed into components in the direction of the vector I * of the current command value and in a direction orthogonal thereto. When the resultant combined voltage vectors v_a0 and v_r0 are again decomposed into dq-axis components, effective voltage components vd_1 * and vq_1 * are obtained from v_a0, and reactive voltage components vd_2 * and vq_2 * are obtained from v_r0. The valid / invalid dq voltage computing means 42c is a means for computing this process, and is performed based on the following equation (in the second invention, obtained from the current phase β and the voltage command value).

Since the voltage component of the dq axis is calculated by vector decomposition / synthesis, the invalid voltage component can also be calculated from the following equation.

If the above equation is used, vd_2 * and vq_2 * can be obtained without calculating v_r0, so that the amount of calculation can be reduced (this corresponds to the fourth invention).

The obtained vd_1 * and vq_1 * use the active power distribution target values (rto_pa_a, rto_pa_b) to perform voltage distribution in order to distribute the power supplied from the power supply 10a and the power supplied from the power supply 10b. . here,
rto_pa_a + rto_pa_b = 1
Thus, the distribution target value can be changed within a range in which the relationship of the distribution ratio is satisfied (corresponding to the sixth invention).
vd1_a * = rto_pa_a ・ vd_1 *
vq1_a * = rto_pa_a ・ vq_1 *
vd1_b * = rto_pa_b ・ vd_1 *
vq1_b * = rto_pa_b ・ vq_1 *

Further, the reactive power distribution target values (rto_pr_a, rto_pr_b) are used to distribute the reactive power circulating through the pole to which the power source 10a is connected and the reactive power circulating through the pole of the power source 10b.
here,
rto_pr_a + rto_pr_b = 1
vd2_a * = rto_pr_a ・ vd_2 *
vq2_a * = rto_pr_a ・ vq_2 *
vd2_b * = rto_pr_b ・ vd_2 *
vq2_b * = rto_pr_b ・ vq_2 *
From the obtained voltages, vd_a * and vq_a * are calculated as voltage command values on the power supply 10a side and vd_b * and vq_b * are calculated as voltage command values on the power supply 10b side using the following equations. This represents the adder 42f in FIG.
vd_a * = vd1_a * + vd2_a *
vq_a * = vq1_a * + vq2_a *
vd_b * = vd1_b * + vd2_b *
vq_b * = vq1_b * + vq2_b *
42f and 42g are dq / 3-phase voltage conversion means for converting the obtained dq-axis voltage command value into a 3-phase voltage command, and output vu_a *, vv_a *, vw_a *, vu_b *, vv_b *, vw_b * To do. Hereinafter, a voltage command generated from the power supply 10a is referred to as a power supply 10a divided voltage command, and a voltage command generated from the power supply 10b is referred to as a power supply 10b divided voltage command.

  45, the voltage Vdc_a of the power supply 10a and the voltage Vdc_b of the power supply 10b are inputted, and the instantaneous modulation rate command mu_a * which is a voltage command obtained by normalizing vu_a *, vu_b *, vv_a *, vv_b *, vw_a *, vw_b * , Mu_b *, mv_a *, mv_b *, mw_a *, and mw_b *. Reference numeral 46 denotes a modulation rate correction unit that performs processing before performing PWM on the instantaneous modulation rate command and generates final instantaneous modulation rate commands mu_a_c *, mu_b_c *, mv_a_c *, mv_b_c *, mw_a_c *, and mw_b_c *. 47 is PWM pulse generation means for generating a PWM pulse for turning on / off each switch of the power converter 30 based on the final instantaneous modulation rate command.

  Hereinafter, the modulation factor calculating unit 45, the modulation factor correcting unit 46, and the PWM pulse generating unit 47 will be described in detail with reference to FIGS. FIG. 5 is a flowchart showing the calculation performed by each means of FIG. The following description is performed only for the U phase, but the same operation is performed for the V phase and the W phase.

Modulation rate calculation means 45
The modulation factor calculation means 45 performs calculation 2 shown in FIG. By normalizing the U-phase power supply 10a voltage command vu_a * and the power supply 10b voltage command vu_b * by half of each DC voltage, the power supply 10a instantaneous modulation rate command mu_a * and the power supply 10b instantaneous modulation rate command Find mu_b *.
mu_a * = vu_a * / (Vdc_a / 2)
mu_b * = vu_b * / (Vdc_b / 2)

電源電圧Ｖdc_a、Ｖdc_ｂと、求められた|Ｖ_a|,|Ｖ_b|を用いて、次の式に基づいて電源10a分瞬時変調率指令ｍu_a*、電源10ｂ分瞬時変調率指令ｍu*_bの補正を行う。

このように、電源10a分瞬時変調率指令ｍu_a*、電源10ｂ分瞬時変調率指令ｍu*_bに分配電力目標値の大きさに応じた値を乗じるとともにオフセット値を減算することで、分配電力目標値の大きさが大きい電源から生成する電圧を大きくできるようにしている。なお、ここでは減算式にて説明したが、最初に固定値を減算した上で補正値を加算する方法を用いても同様の効果となる。つまり加算もしくは減算を行うことで任意の電力分配比を達成できる。 Modulation rate correction means 46 (equivalent to the seventh invention)
The modulation factor correction means 46 performs calculation 3 shown in FIG. In this calculation, first, the magnitudes | V_a | and | V_b | of the voltage vectors a and b are obtained from vd_a *, vq_a *, vd_b *, and vq_b *.

Using the power supply voltages Vdc_a and Vdc_b and the obtained | V_a | and | V_b |, the correction of the instantaneous modulation factor command mu_a * for the power supply 10a and the instantaneous modulation factor command mu * _b for the power supply 10b is performed based on the following formula. Do.

In this way, the power supply 10a instantaneous modulation rate command mu_a * and the power supply 10b instantaneous modulation rate command mu * _b are multiplied by a value corresponding to the size of the distributed power target value and the offset value is subtracted to thereby obtain the distributed power target. The voltage generated from the power supply having a large value can be increased. Although the subtraction formula is used here, the same effect can be obtained by using a method of adding a correction value after first subtracting a fixed value. That is, any power distribution ratio can be achieved by performing addition or subtraction.

PWM pulse generation means 47
In FIG. 6, a carrier for the power source 10a is a triangular wave carrier for generating PWM pulses for driving each switch in order to output a voltage pulse from the voltage Vdc_a of the power source 10a. Similarly, a triangular wave is used as the carrier for the power source 10b. Is provided. These two triangular wave carriers have values of an upper limit of +1 and a lower limit of -1, and have a phase difference of 180 degrees. Here, the signals for driving the U-phase switches are set as follows based on FIG.
A: Switch drive signal conducting from the power supply 10a to the output terminal B: Switch drive signal conducting from the output terminal to the negative electrode C: Switch drive signal conducting from the output terminal to the power supply 10a D: Power supply Switch drive signal conducting from 10b to output terminal E: Switch drive signal conducting from output terminal to power supply 10b

  First, a pulse generation method when a voltage pulse is output from the power supply 10a will be described. When outputting a PWM pulse from the power supply 10a, it is necessary to turn on A. When there is a potential difference between the positive electrode and the positive electrode and Vdc_a> Vdc_b, when both A and E are turned on, a current that short-circuits between the positive electrodes flows. For example, when A is switched from on to off at the same time and E is switched from off to on, it takes time for A to completely turn off. A short-circuit current flows, and the amount of heat generated by the semiconductor switch installed in this path increases. In order to prevent such an increase in heat generation, A and E are switched from OFF to ON after a time during which both the drive signals A and E are turned off. In this way, pulse generation is performed by adding a short-circuit prevention time (dead time) to the drive signal. Similar to adding dead time to the drive signals of A and E, dead time is added to E and C, and in order to prevent a short circuit between the positive and negative electrodes, dead to A and B and E and B. Add time.

A method for adding dead time to the A and E drive signals will be described below with reference to FIG.
In order to generate a drive signal with a dead time added, mu_a_c_up * and mu_a_c_down * offset from the mu_a_c * by the dead time are obtained as follows.
mu_a_c_up * = mu_a_c * + Hd
mu_a_c_down * = mu_a_c * − Hd
Here, Hd is obtained from the amplitude of the triangular wave (from the base to the apex) Htr, the period Ttr, and the dead time Td as follows.
Hd = 2Td · Htr / Ttr
The carrier and mu_a_c *, mu_a_c_up *, mu_a_c_down * are compared, and the drive signals for the A and E switches are obtained according to the following rules.
mu_a_c_down * ≧ If carrier for power supply 10a A = ON
If mu_a_c * ≤ carrier for power supply 10a, A = OFF
If mu_a_c * ≧ carrier for power supply 10a, E = OFF
mu_a_c_up * ≤ Carrier for power supply 10a E = ON
Thus, by generating the drive signal, a dead time of Td can be provided between A and E, and a short circuit between the positive electrodes can be prevented.

The pulse generation method for outputting voltage pulses from the power supply 10b is the same as that for the power supply 10a, and the following mu_b_c_up * and mu_b_c_down * are obtained and compared with the carrier for the power supply 10b (FIG. 9).
mu_b_c_up * = mu_b_c * + Hd
mu_b_c_down * = mu_b_c * − Hd
The drive signals for the D and C switches are obtained according to the following rules.
If mu_b_c_down * ≥ carrier for power supply 10b, D = ON
If mu_b_c * ≤ carrier for power supply 10b, D = OFF
If mu_b_c * ≧ carrier for power supply 10b, C = OFF
If mu_b_c_up * ≤ carrier for power supply 10b, C = ON
In this way, a dead time of Td can be provided between D and C, and a short circuit between the positive electrodes can be prevented.

The drive signal B is generated from the AND of the drive signals E and C generated using an AND circuit or the like.
B = E ・ C
E is a drive signal with a dead time added to A, and C is a drive signal with a dead time added to D. Therefore, by generating B from the AND of E and C, it is possible to generate dead time for B and A and B and E as well. An example of pulse generation with a dead time added is shown in FIG.
According to the present invention, it is possible to control the power distribution for the power sources 10a and b by dividing them into active power and reactive power. When the active power distribution target value rto_pa_a = 1 and the reactive power distribution target value rto_pr_a = 0, the active power for driving the motor is supplied only from the power source 10a, and the reactive power passes through the pole to which the power source 10b is connected. Each phase is circulated, and considering the average power of the power supply 10b, no discharge occurs. For this reason, the power source 10b may be a small-capacity power source or a configuration having only the smoothing capacitor 13 as shown in FIG. 14 (corresponding to the eighth invention).

  T1 in FIG. 13 shows speed / torque characteristics when an SPM (surface magnet type) motor is driven by a general inverter having the same DC voltage as that of the power supply 10a. The region where the torque is constant at a low speed is as follows. The region is mainly limited by the upper limit value of the current of the motor / inverter, and the region in which the torque decreases with rotation is a region in which the voltage for flowing the motor current decreases due to the induced voltage of the motor. On the other hand, T2 uses the same motor as T1 and the method for controlling the power converter according to the present invention, charges the voltage of the smoothing capacitor 13 to 5 times that of the power supply 10a, supplies active power only from the power supply 10a, and disables it. The speed / torque characteristics are shown when power is supplied only from the path connected to the smoothing capacitor 13 corresponding to the power source 10b. The torque upper limit value at low speed is not different because the upper limit value of the current is equal to T1, but the output torque can be significantly improved in the high rotation region. This is because, in the high rotation range of T1, a large amount of reactive current flows to the motor to suppress the induced voltage, so the ratio of effective current that can be generated as torque is low and the power factor is low. On the other hand, at T2, the reactive current is circulated through the smoothing capacitor 13, and the voltage of the smoothing capacitor 13 is kept high to suppress the induced voltage of the motor. From the power source 10a, the effective current that can be generated as the motor torque As a result, it is possible to supply a larger amount of voltage for causing the output to flow, so that the output torque can be improved. Thus, according to the present invention, it is possible to reduce the loss and volume of the DCDC converter booster circuit while exhibiting the same effect as the speed / torque characteristics without using the conventional DCDC converter booster circuit. become.

  A second embodiment will be described with reference to FIG. An inverter 205 connected to a power source 202 is an inverter that converts a generally known direct current into a three-phase alternating current. A smoothing capacitor 204 is connected between the inverter and the power source. A three-phase transformer 201 is connected between the inverter 205 and the motor 20, and one of the three-phase transformers is connected to the inverter 206. The inverter 206 is connected to a capacitor 203 corresponding to a smoothing capacitor that functions as a power source. As shown in FIG. 16, the control of these two inverters is performed up to the modulation factor calculation means 45 through the same procedure as the control calculation in the first embodiment. The obtained modulation rate is generated by PWM generation by the PWM pulse generation means 47a, and pulse generation by triangular wave comparison performed by a normal inverter is performed, and the switch of the inverter 205 is driven using mu_a *, mv_a *, mw_a * Similarly, a drive signal for the inverter 206 is generated using mu_b *, mv_b *, and mw_b *. The voltages generated by the inverters 205 and 206 are combined via a three-phase transformer and supplied to the motor. As in the first embodiment, the active power distribution target value rto_pa_a = 1, the reactive power distribution target value rto_pr_a = 0, and the voltage of the capacitor 203 is set higher than the voltage of the power supply 202, The output torque as shown in FIG. 13 can be improved.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention.

It is a figure which shows the structure of the conventional motor control system. It is a block diagram which shows an example of the motor control system suitable for use of the control method of the power converter device by this invention. It is an example of the circuit diagram of the power converter device suitable for use of the control method of the power converter device by this invention. It is the figure which extracted a part of FIG. It is a flowchart which shows the calculation of each block of FIG. It is a figure which shows the calculation in the PWM pulse production | generation means of 1st Example. It is a figure which shows the structure which extracted only the U phase from FIG. It is a figure which shows the pulse generation of A and E by a triangular wave comparison. It is a figure which shows the pulse generation of D and C by a triangular wave comparison. It is a figure which shows the example of the pulse generation to which the dead time was added. It is a control block diagram of a part of the control system of FIG. It is a vector diagram explaining valid / invalid voltage. It is a speed-torque characteristic diagram of a motor. It is a figure which shows another structure of the power converter in a 1st Example. It is a figure which shows the structure of the power converter in a 2nd Example. It is a figure which shows the structure of the control system of a 2nd Example.

Explanation of symbols

10a, 10b power supply
12,13 Smoothing capacitor
14 Positive bus of power supply 10a
15 Common negative electrode bus
16 Power supply 10b positive bus
20 Motor
101a / 101b, 102a / 102b, 103a / 103b Semiconductor switch
104a / 104b, 105a / 105b, 106a / 106b semiconductor switch
107a, 108a, 109a Semiconductor switch
107b, 108b, 109b Diode
30 Power converter
30U U-phase switch group
30V V-phase switch group
30W W phase switch group
40 Control unit
41 Torque control means
42 Current control means
43 dq / 3-phase voltage conversion means
44 Voltage distribution means
45 Modulation rate calculation means
46 Modulation rate correction means
47,47a PWM pulse generation means
48 Three-phase / dq voltage conversion means
202 power supply
201 Three-phase transformer
203 Capacitor (acts as a power supply)
204 capacitor
205,206 Inverter

Claims (8)

A method for controlling a power converter that is connected to a plurality of DC power supplies, generates a drive voltage by generating and synthesizing pulses from the output voltages of each of these DC power supplies, and drives an AC motor,
An effective voltage command value generation step for generating an effective voltage command value that is a motor voltage component in phase with the motor current;
A reactive voltage command value generation step for generating a reactive voltage command value that is other motor voltage component;
A voltage distribution step of distributing the effective voltage command value and the reactive voltage command value to each voltage command value corresponding to each of a plurality of DC power sources;
Controlling the power converter to generate each output voltage pulse based on each voltage command value; and
The control method of the power converter device characterized by including. In the control method of the power converter device according to claim 1,
The voltage command value generation step includes
Extracting the effective voltage command value from the motor voltage command value and the motor current phase,
The reactive voltage command value generation step includes
The reactive voltage command value is extracted from the motor voltage command value and the motor current phase.
A method for controlling a power conversion device. In the control method of the power converter device according to claim 2,
Furthermore, the step of obtaining the phase of the motor current from the phase of the command value of the motor current,
The control method of the power converter device characterized by including. In the control method of the power converter device according to claim 2,
The reactive voltage command value generation step includes
Obtaining the reactive voltage command value by subtracting the effective voltage command value from the motor voltage command value;
A method for controlling a power conversion device. In the control method of the power converter device according to claim 2,
And a step of calculating a dq-axis voltage command value for controlling the dq-axis current from the dq-axis current command value and the dq-axis current in the dq coordinate,
The effective voltage command value generation step includes
The effective voltage command value is extracted from the dq axis current command value and the dq axis voltage command value,
The reactive voltage command value generation step includes
The reactive voltage command is extracted from the dq axis current command value and the dq axis voltage command value.
A method for controlling a power conversion device. In the control method of the power converter device according to claim 1,
The voltage distribution step comprises:
Multiplying the effective voltage command value by the active power distribution command value corresponding to each of the plurality of DC power sources to obtain a distributed effective voltage command;
Multiplying the reactive voltage command value corresponding to each of the plurality of DC power supplies by the reactive voltage command value to obtain a post-distributed reactive voltage command;
Obtaining each voltage command value corresponding to each of the plurality of DC power sources from the sum of the distributed effective voltage command value and the distributed reactive voltage command value, respectively.
A method for controlling a power conversion device. In the control method of the power converter device according to claim 6,
Further, each voltage command value corresponding to each of the plurality of DC power supplies is obtained by normalizing each voltage command value by the voltage value of the DC power supply, and each voltage command Outputting each correction modulation rate command value by adding or subtracting an offset amount corresponding to the magnitude of the value;
The control method of the power converter device characterized by including. In the control method of the power converter device of any one of Claims 1-7,
Further, one of the plurality of DC power supplies is a capacitor, and the reactive voltage command value is a voltage command value corresponding to the power stored in the capacitor,
The control method of the power converter device characterized by including.

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