JP5659620B2 - Control device for power converter - Google Patents

Description

  The present invention relates to a control device for a power converter that controls a power converter such as a converter or an inverter.

  In the switching method of the power converter, a dead time is set so that the positive side and negative side switching elements do not pass simultaneously. For this reason, a difference appears between the voltage command value obtained by the control calculation and the value of the voltage actually output by PWM by the power conversion. Due to this difference, the output voltage is distorted and current pulsation occurs.

  In order to solve this problem, the polarity of the detection voltage of the output current of the power converter or the polarity of the current command is used to determine the polarity of the compensation voltage for the dead time, and the amplitude of the compensation voltage is determined according to the current magnitude What is determined has been proposed (see, for example, Patent Document 1).

  In such a case, the basic value of the amplitude of the compensation voltage is tuned by measuring the hardware characteristics at the design stage. For example, tuning is performed based on the measurement result in a special mode for adjusting the voltage compensation error so that the output current of a phase of the power converter becomes 0 (see, for example, Patent Document 2).

JP-A-3-135389 JP 2000-184732 A

  However, tuning may not be performed appropriately due to individual differences in hardware such as a shift in the on / off time of the switching element.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a control device for a power converter capable of appropriately tuning the amplitude of the compensation voltage for dead time. .

The control device for the power converter according to the present invention includes a storage unit that stores a compensation voltage for suppressing a voltage supplied from the power converter to the electric motor from being distorted by a dead time set in the power converter; When the power converter is controlled based on the combined voltage command obtained by adding the compensation voltage to the voltage command corresponding to the current ideal command, and when the driving force of the electric motor based on the combined voltage command is excessive or insufficient, Adjusting means for adjusting the driving force by adjusting the value of the driving current flowing from the power converter to the electric motor, and current pulsation generated on the driving current when the value of the driving current is adjusted as the difference value between the value of the current ideal command is smaller than a predetermined reference value, after completing the correction of the amplitude of the compensation voltage, and correcting means for correcting the phase of the compensation voltage, the Those were example.

  According to the present invention, the amplitude of the compensation voltage for dead time can be appropriately tuned.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the elevator system with which the control apparatus of the power converter in Embodiment 1 of this invention is utilized. It is a block diagram of the Td correction | amendment calculating means utilized for the control apparatus of the power converter in Embodiment 1 of this invention. It is a figure for demonstrating the state where the amplitude of the compensation voltage of a dead time is not optimal. It is a figure for demonstrating the state where the phase of the compensation voltage of a dead time is not optimal. It is a block diagram of the Td correction | amendment amplitude calculating means utilized for the control apparatus of the power converter in Embodiment 1 of this invention. It is a block diagram of the Td correction phase calculation means utilized for the control apparatus of the power converter in Embodiment 1 of this invention.

  A mode for carrying out the invention will be described with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

Embodiment 1 FIG.
1 is a configuration diagram of an elevator system in which a control device for a power converter according to Embodiment 1 of the present invention is used.

  In FIG. 1, 1 is a power converter. The power converter 1 includes a converter, a DC bus, a capacitor, and an inverter (both not shown). The converter has a function of rectifying AC power and converting it to DC power. The DC bus has a function of transmitting DC power input from the converter. The capacitor has a function of removing the influence of a pulsating current on the DC bus. The inverter has a function of converting DC power input from a DC bus into AC power having an appropriate variable voltage and variable frequency.

  2 is a hoisting machine. The hoisting machine 2 is provided in the upper part of the elevator hoistway (not shown). The hoisting machine 2 includes a synchronous motor 3, a sheave 4, and a brake 5. The stator of the synchronous motor 3 is provided with a coil. The coil is connected to the inverter of the power converter 1. On the other hand, the rotor of the synchronous motor 3 is provided with a permanent magnet. The sheave 4 is provided on the rotor shaft of the synchronous motor 3. The brake 5 is provided inside the sheave 4. The brake 5 has a function of braking the rotational drive of the sheave 4.

  A baffle (not shown) is provided near the sheave 4 above the hoistway as necessary. A suspension rope 6 is wound around the sheave 4 and the deflector. A counterweight 7 is connected to one end of the suspension rope 6. The counterweight 7 is disposed in the hoistway. On the other hand, a basket 8 is connected to the other end of the suspension rope 6. The basket 8 is also arranged in the hoistway. The roping method is arbitrary, such as a 1: 1 method or a 2: 1 method. The elevator is not limited to a traction type elevator, and may be a winding type elevator.

  An encoder 9 is provided in the vicinity of the sheave 4. The encoder 9 has a function of detecting the rotational speed of the synchronous motor 3. A control block 10 is connected to the encoder 9. The control block 10 includes a rotation speed / magnetic pole position calculation means 11, a cage position calculation means 12, a basket load detection means 13, a speed pattern generation means 14, a speed controller 15, a current controller 16, a two-phase three-phase converter 17, Td correction calculation means 18 is provided.

  In the elevator, the rotation speed / magnetic pole position calculation means 11 calculates the rotation speed and the magnetic pole position of the synchronous motor 3 based on the output of the encoder 9. The car position calculation means 12 calculates the position of the car 8 based on the output of the encoder 9. The car load detecting means 13 measures the car weight including the passenger as the car load. The speed pattern generation unit 14 generates a speed pattern of the car 8 based on the car load, the car position, and the next stop position information.

  The speed controller 15 calculates a current command (q-axis current command) based on the speed command obtained from the speed pattern generation unit 14 and the rotation speed obtained from the rotation speed / magnetic pole position calculation unit 11. The current controller 16 compares the current command obtained from the speed controller 15 with the current value (q-axis current value) flowing into the synchronous motor 3. Based on the comparison result and the magnetic pole position obtained from the rotation speed / magnetic pole position calculating means 11, the current controller 16 calculates an appropriate two-phase voltage command.

  This two-phase voltage command is converted into a three-phase voltage command by the two-phase three-phase converter 17. Further, the Td correction calculating means 18 supplies the supply voltage according to the dead time set in the power converter 1 based on the motor frequency obtained from the speed controller 15, the current ideal command I ideal and the current value flowing into the synchronous motor 3. The Td correction amount is calculated as a compensation voltage for preventing the distortion. The power converter 1 supplies a current to the coil of the synchronous motor 3 based on the combined voltage command obtained by adding the Td correction amount to the three-phase voltage command.

  With this current supply, the rotor of the synchronous motor 3 rotates. Following this rotation, the sheave 4 rotates. Following the rotation, the hanging rope 6 moves. Following this movement, the counterweight 7 and the cage 8 move up and down in opposite directions.

Next, the Td correction calculation means 18 will be described with reference to FIG.
FIG. 2 is a block diagram of Td correction calculation means used in the power converter control apparatus according to Embodiment 1 of the present invention.
As shown in FIG. 2, the Td correction calculation means 18 includes a Td correction amplitude calculation means 19 and a Td correction phase calculation means 20.

  The motor frequency and the current ideal command I ideal flow from the speed controller 15 to the Td correction amplitude calculation means 19. This ideal current command I ideal is the same as the current command sent from the speed controller 15 to the current controller 16. Further, the current detection value flowing into the synchronous motor 3 is input to the Td correction calculation means 18. The Td correction amplitude calculating means 19 optimizes the dead time compensation voltage amplitude based on the motor frequency, the current ideal command I ideal and the current detection value. The optimized one is sent out as the first Td correction amount. When the optimization is completed, a correction amplitude adjustment completion signal is sent out.

  The motor frequency is input to the Td correction phase calculation means 20 from the speed controller 15 via the Td correction amplitude calculation means 19. A detected current value that flows into the synchronous motor 3 via the Td correction amplitude calculation means 19 is input to the Td correction phase calculation means 20. The Td correction phase calculation unit 20 receives the first Td correction amount and the correction amplitude adjustment completion signal from the Td correction amplitude calculation unit 19. The Td correction amplitude calculation means 19 optimizes the phase of the compensation voltage for dead time based on the motor frequency and the current detection value. The optimized one is sent out as the second Td correction amount.

Here, the case where the dead time compensation voltage is not optimized will be described with reference to FIGS. 3 and 4.
FIG. 3 is a diagram for explaining a state in which the amplitude of the compensation voltage for dead time is not optimal.
The horizontal axis in FIG. 3 represents time. The vertical axis in FIG. 3 is the amount of current.

  FIG. 3A shows the current command iqs when the compensation voltage for dead time is too small. In this case, the synchronous motor 3 becomes insufficient in torque (driving force). This situation is compensated for a period of time by the current feedback loop. Due to this compensation, current pulsation occurs. That is, the current command iqs sent by the current controller 16 rises for a certain period from the time when the current value zero-crosses from minus to plus and then falls. This change in the current command iqs is repeated at a cycle 6 times the motor frequency.

  FIG. 3B shows the current command iqs when the amplitude of the dead time compensation voltage is excessive. In this case, the synchronous motor 3 has excessive torque (driving force). This situation is compensated for a period of time by the current feedback loop. Due to this compensation, current pulsation occurs. That is, the current command iqs sent out by the current controller 16 rises after falling for a certain period from the time when the current value zero-crosses from minus to plus. This change in the current command iqs is repeated at a cycle 6 times the motor frequency.

  As described above, the current controller 16 also functions as an adjusting unit that adjusts the torque (driving force) of the synchronous motor 3. In this embodiment, the Td correction amplitude calculation means 19 is set to the dead time so that the deviation between the value of the current command iqs and the current ideal command I ideal is smaller than the predetermined Td correction amount deviation reference value A. The compensation voltage amplitude is corrected.

FIG. 4 is a diagram for explaining a state in which the phase of the compensation voltage for dead time is not optimal.
The horizontal axis of FIG. 4 represents time. The vertical axis in FIG. 4 is the amount of current.

  FIG. 4 shows the detected current value iq when the phase of the dead time compensation voltage is delayed. Originally, the polarity of the compensation voltage of the dead time is reversed when the positive / negative of the current detection value iq is reversed. However, when the phase of the compensation voltage for dead time is delayed, the correction direction is reversed. This situation is compensated for a certain time by the current feedback loop. Due to this compensation, current pulsation occurs. That is, the current detection value iq rises after falling for a certain period from the time when the current value zero-crosses from minus to plus, or falls after rising for a certain period. This change in the detected current value iq is repeated at a cycle 6 times the motor frequency. The same applies when the phase of the dead time compensation voltage is advanced.

  In the present embodiment, when the difference between the value of the current detection value iq and the current ideal command I ideal is equal to or greater than a predetermined Td correction amount deviation reference value B, the Td correction phase calculation means 20 It is determined whether or not a current pulsation has occurred within a predetermined phase reference time Tph from when the value is reversed. When the current pulsation does not occur within the phase reference time Tph, the phase of the dead time compensation voltage is corrected so that the pulsating current is generated within the phase reference time Tph.

Next, a method for optimizing the dead time compensation voltage will be described in detail.
First, the optimization of the amplitude of the compensation voltage will be described with reference to FIG.
FIG. 5 is a block diagram of Td correction amplitude calculation means used in the power converter control apparatus according to Embodiment 1 of the present invention.

  As shown in FIG. 5, the Td correction amplitude calculation unit 19 includes a storage unit 21, a current zero cross determination unit 22, a 6-fold period determination unit 23, and a correction amplitude excess / deficiency determination unit 24.

  The storage means 21 stores the value of the dead time compensation voltage (design Td). The detected values of the current Iu and the current Iv are input to the current zero cross determination means 22. The current zero cross determination means 22 subtracts the current Iu value and the current Iv value from 0 to obtain the current Iw value. The current zero cross determination means 22 determines the timing at which the value of the current Iu, the value of the current Iv, and the value of the current Iw are determined from negative to positive.

  A motor frequency is input to the 6-times cycle determination means 23. The 6-times cycle determination means 23 determines that the motor frequency is synchronized with the timing determined by the current zero cross determination means 22. As a result, it can be seen that a pulsating current is generated due to excessive or insufficient dead time compensation voltage. That is, the 6-fold period determining unit 23 functions as a detecting unit that detects a pulsating current.

  The current ideal command I ideal is input from the speed controller 15 to the corrected amplitude excess / deficiency determination means 24. The current command iqs is input from the current controller 16 to the corrected amplitude excess / deficiency determination means 24. The corrected amplitude excess / deficiency determining means 24 calculates the deviation between the current ideal command I ideal and the current command iqs. The corrected amplitude excess / deficiency determining means 24 compares the calculated deviation with the Td correction amount deviation reference value A.

  When current command iqs−ideal current command Iqideal> + A, the correction amplitude excess / deficiency determination means 24 selects “+ ΔTd”. In the case of current command iqs−ideal current command I ideal> −A, the correction amplitude excess / deficiency determination means 24 selects “−ΔTd”. Each selected value is summed with the compensation voltage stored in the storage means 21. This sum value is sent out as the first Td correction amount. Further, the value of the compensation voltage in the storage means 21 is rewritten by the sum value.

  When | current command iqs−ideal current command I ideal | <A, the corrected amplitude excess / deficiency determining means 24 selects “0”. In this case, a correction amplitude adjustment completion signal is sent out.

  In the present embodiment, the above operation is repeated. As a result, the amplitude of the compensation voltage for dead time is determined.

Next, the optimization of the phase of the compensation voltage will be described with reference to FIG.
FIG. 6 is a block diagram of a Td correction phase calculation means used in the power converter control apparatus according to Embodiment 1 of the present invention.

  The Td correction phase calculation unit 20 includes a polarity determination unit 25, a current zero cross determination unit 26, a 6-times cycle determination unit 27, a first correction phase determination unit 28, and a second correction phase determination unit 29.

  The polarity determination unit 25 includes an Iu polarity determination unit 25a, an Iv polarity determination unit 25b, and an Iw polarity determination unit 25c. The detected value of the current Iu is input to the Iu polarity determination means 25a. The Iu polarity determination means 25a determines the correction direction of the Td correction amount from the polarity of the current Iu. The detected value of the current Iv is input to the Iv polarity determination means 25b. The Iv polarity determination means 25b determines the correction direction of the Td correction amount from the polarity of the current Iv. The detection value of the current Iu and the detection value of the current Iv are input to the Iw polarity determination means 25c. The Iw polarity determination means 25c subtracts the current Iu value and the current Iv value from 0 to obtain the current Iw value. The Iw polarity determination means 25c determines the correction direction of the Td correction amount from the polarity of the current Iw.

  The detected value of the current Iu and the detected value of the current Iv are input to the current zero cross determining means 26. The current zero cross determination means 26 subtracts the value of the current Iu and the value of the current Iv from 0 to obtain the value of the current Iw. The current zero cross determination means 26 determines the timing when the value of the current Iu, the value of the current Iv, and the value of the current Iw change from minus to plus or from plus to minus.

  The motor frequency is input to the 6-times cycle determination means 27. The 6-times cycle determination unit 27 determines that the motor frequency is synchronized with the timing determined by the current zero cross determination unit 26. As a result, it can be seen that a pulsating current is generated due to excessive or insufficient dead time compensation voltage. That is, the 6-fold period determining unit 27 functions as a detecting unit that detects a pulsating current.

  The current ideal command I ideal is input from the speed controller 15 to the first correction phase determination means 28. The current command iqs is input from the current controller 16 to the first correction phase determination unit 28. The first correction phase determination means 28 calculates a deviation between the current ideal command I ideal and the current command iqs. The first correction phase determination means 28 compares the calculated deviation with a predetermined Td correction amount deviation reference value B. When | current command iqs−ideal current command I ideal |> B, the first correction phase determination means 28 determines that the phase of the compensation voltage is not optimal.

  The second correction phase determination unit 29 operates only when the correction amplitude adjustment completion signal is input. That is, the correction amplitude adjustment completion signal is a trigger signal for performing the phase of the dead time compensation voltage. When it is determined that the correction of the compensation voltage is not optimal, the second correction phase determination unit 29 corrects the phase of the compensation voltage.

  Specifically, when the occurrence of the deviation is more than the phase reference time Tph more than the timing determined by the current zero-cross determination unit 26, the second correction phase determination unit 29 selects “+ Δθ”. When the occurrence of the deviation is delayed by more than the phase reference time Tph from the timing determined by the current zero cross determination unit 26, the second correction phase determination unit 29 selects “−Δθ”. When the occurrence of the deviation is within the phase reference time Tph, “0” is selected as the second correction phase.

  The selected value is added to the phase in the direction determined by the polarity determination means 25. The Td correction amount corresponding to this phase is sent out as the final second Td correction amount. The summed phase is stored in the polarity determination means 25 as a default phase difference.

  In the present embodiment, the above operation is repeated. Thereby, the phase of the compensation voltage for dead time is determined.

  According to the first embodiment described above, the amplitude of the compensation voltage for the dead time is corrected so that the difference between the value of the current pulsation and the value of the current ideal command I ideal is smaller than a predetermined reference value. Therefore, the amplitude of the compensation voltage for dead time can be optimally tuned without using a device for measuring the voltage. Thereby, it is possible to automate the parameter confirmation at the design stage. That is, design labor can be realized.

  Variations in performance due to individual differences of the power converter 1 can be improved. Specifically, on the inverter side, it is possible to suppress the occurrence of torque pulsation having a period that is six times the motor frequency. For this reason, the vibration of the motor can be suppressed. Further, on the converter side, power supply pulsation having a period of 6 times the power supply frequency can be suppressed. For this reason, it can suppress that a high frequency component propagates to the power supply side.

  In addition, the phase of the compensation voltage is corrected so that current pulsation occurs within a predetermined time from when the positive / negative value of the drive current value is reversed. Therefore, the phase of the compensation voltage for dead time can be optimally tuned.

  Further, after the correction of the amplitude of the dead time compensation voltage is completed, the phase of the dead time compensation voltage is corrected. For this reason, parameter adjustment can be performed efficiently.

  Furthermore, when the starting point of the current pulsation is synchronized with the time point when the value of the driving current is reversed, the generation of the pulsating current is detected. For this reason, it is possible to prevent the dead time compensation voltage from being tuned due to sudden noise or the like.

  Note that the above-described effect can be obtained by using either the value of the current command Iqs of the current controller 16 or the actual detected current value as the value of the pulsating current to be compared with the current ideal command Iqideal.

DESCRIPTION OF SYMBOLS 1 Power converter 2 Hoisting machine 3 Synchronous motor 4 Sheave 5 Brake 6 Hanging rope 7 Balance weight 8 Basket 9 Encoder 10 Control block 11 Rotation speed and magnetic pole position calculation means 12 Basket position calculation means 13 Basket load detection means 14 Speed pattern Generation means 15 Speed controller 16 Current controller 17 Two-phase three-phase converter 18 Td correction calculation means 19 Td correction amplitude calculation means 20 Td correction phase calculation means 21 Storage means 22 Current zero cross determination means 23 6-times period determination means 24 Correction Amplitude excess / deficiency determination means 25 Polarity determination means 25a Iu polarity determination means 25b Iv polarity determination means 25c Iw polarity determination means 26 Current zero cross determination means 27 Six-fold period determination means 28 First correction phase determination means 29 Second correction phase determination means

Claims (3)

Storage means for storing a compensation voltage for suppressing the voltage supplied from the power converter to the electric motor from being distorted by a dead time set in the power converter;
When the power converter is controlled based on the combined voltage command obtained by adding the compensation voltage to the voltage command corresponding to the current ideal command, and when the driving force of the electric motor based on the combined voltage command is excessive or insufficient, Adjusting means for adjusting the driving force by adjusting the value of the driving current flowing from the power converter into the electric motor;
The amplitude of the compensation voltage is reduced so that the difference between the value of the current pulsation generated on the drive current when the value of the drive current is adjusted and the value of the current ideal command is smaller than a predetermined reference value . Correction means for correcting the phase of the compensation voltage after completing the correction;
An apparatus for controlling a power converter, comprising:   2. The electric power according to claim 1, wherein the correction unit corrects the phase of the compensation voltage so that the current pulsation is generated within a predetermined time from the point in time when the value of the drive current is reversed. Control device for the converter. It said correction means, if the starting point of the current pulse is synchronized to the time when the positive and negative reversed value of the drive current, according to claim 1 or claim, characterized in that detecting the occurrence of said current pulse The control apparatus of the power converter of 2 .

Images