JP4625664B2 - Inverter drive blower controller - Google Patents

Description

  The present invention relates to an inverter-driven blower control device.

  In electric equipment for trains, there is a demand for weight reduction of installed equipment for the purpose of speeding up the vehicle, and improvement in equipment efficiency from the viewpoint of energy saving. A single-phase induction motor has been used as a blower device for cooling the main motor. However, application of a permanent magnet synchronous motor (PMSM), which can be reduced in size and weight and is excellent in efficiency, is expected.

  However, when using PMSM, it is necessary to provide an inverter as compared with the conventional system, resulting in a high-cost system. Also, in this system, it is not preferable to equip each PMSM with a sensor such as a position detector or a rotational speed detector because it leads to further increase in cost and reliability, and a sensorless system that does not use the detector. Realization of is desired.

  In the case of the sensorless system, since the certainty at the time of starting the apparatus is reduced, the time during which the rated air volume cannot be output increases, and there is a possibility that the system reliability due to the air volume reduction is impaired. Even in the sensorless system, once it can be driven stably, stable operation can continue, but when the blower device is operated for the first time or after restarting the device, the operation should be started quickly. Is difficult.

  In the current AC train, there is a section called a dead section where power supply is stopped at intervals of several tens of kilometers. Since the power supply is stopped for several seconds while passing through the dead section, it is assumed that the inverter of the blower apparatus frequently stops protection, and the above situation frequently occurs.

As described above, since the cost of a blower device using PMSM tends to increase, a system in which a plurality of PMSMs are connected in series with one inverter is advantageous in terms of suppressing the increase in cost. However, in such a system, the position and speed of the rotors of a plurality of PMSMs are unknown because they are sensorless, and considering the situation where the load of the two PMSMs is unbalanced, each rotor There can be situations where the magnet position or rotor speed is mismatched.
JP 2003-18887 A

  The present invention has been made in view of such a technical problem, and can suppress an increase in cost caused by driving a permanent magnet motor with an inverter, and can achieve small size, light weight and high efficiency. To provide an inverter-driven blower controller with high system reliability that can continue to operate the blower without protection even when it stops, and can quickly and reliably shift to steady operation when power is restored. With the goal.

The inverter-driven blower control device according to the first aspect of the present invention is connected to the converter that is supplied with power from the AC power source and converts AC to DC, the filter capacitor that smoothes the voltage on the output side of the converter, and the filter capacitor. Inverter, a plurality of permanent magnet synchronous motors connected in series to the plurality of blowers to rotate each of the plurality of blowers, and inverter control means for outputting a predetermined output frequency and output voltage to the inverter A power failure detection means for detecting a power failure of the AC power source, a DC voltage detection means for detecting a DC voltage of the inverter, and a direct current detected by the DC voltage detection means when the power failure detection means detects a power failure. based on the voltage, the torque control in which the DC voltage to control the torque of the permanent magnet synchronous motor so as to match the predetermined voltage And the step, and is characterized in that said power failure detecting means and means for passing a current value to a positive perpendicular to the output voltage of the inverter upon detection of a power failure.

  According to the present invention, a permanent magnet motor for rotationally driving a blower for forcibly cooling a main motor can be stably driven even when power supply from a power supply is stopped. It is possible to provide an inverter-driven blower control device that can improve the reliability of the inverter.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  (First Embodiment) FIG. 1 is a block diagram of an inverter drive blower control apparatus according to a first embodiment of the present invention. Single-phase alternating current fed from the substation is collected by the pantograph 7 and the wheels 8. The collected single-phase AC power is converted from a high voltage of the overhead wire to a low voltage by the main transformer 9 and input to the rectifier 10. A filter capacitor 2 and an inverter 1 are provided on the DC side of the rectifier 10. As a load of the inverter 1, two permanent magnet synchronous motors (PMSM) 3 and 4 are connected in series. These PMSMs 3 and 4 are drive sources for the blowers 26 and 27.

The configuration on the control side with respect to the above main circuit configuration will be described. The control device includes three switchers 16, 17, and 24, and switches between a normal control state and a control state during a power failure. The voltage detector 6 detects the output voltage Vc of the main transformer 9, and the power failure detection unit 12 determines whether the state is a healthy state or a power failure state based on the detected voltage Vc detected by the voltage detector 6. For example, the power failure detection flag Flg_NoVs is determined as follows.

  However, VcRms is an effective value (RMS) of Vc, α and β are set values having a relationship of β> α> 0, a power failure detection flag Flg_NoVs = 1 is a power failure state, and Flg_NoVs = 0 is a power healthy state. Represents.

Depending on the power failure detection flag Flg_NoVs output by the power failure detection unit 12, the circuit is switched between a power failure detection state and a healthy state. Here, first, the healthy state (Flg_NoVs = 0) will be described. At this time, the outputs of the switches 16 and 17 are set to zero. The output of the switch 16 is a D-axis voltage command Vd ^* . The adder 18 adds the Q-axis voltage feedforward value VqFF to the output of the switch 17 (here, 0) and outputs the result as a Q-axis output voltage command Vq ^* . Here, VqFF is an output voltage in a healthy state, and is determined by the following equation in proportion to the inverter output frequency ωInv.

Here, K is a coefficient that substantially matches the sum of the magnetic fluxes of the two PMSMs 3 and 4. An inverter output frequency command ωInv that specifies the rotation speed of the blowers 26 and 27 is input to the integrator 23. The integrator 23 integrates the inverter output frequency command ωInv and outputs an output phase angle reference Θ ^* . In the power healthy state, the output phase angle reference Θ ^* is not corrected by the adder 25, that is, 0 is added and output as the phase angle θ. This θ represents the phase angle from the U phase to the rotating coordinate system D axis. The coordinate converter 19 uses the phase angle θ to convert the DQ axis output voltage commands Vd ^* and Vq ^* into voltage command values Vu ^* , Vv ^* , and Vw ^* in a three-phase stationary coordinate system. The coordinate converter 21 converts the phase currents Iu and Iw detected by the current detector 5 into DQ axis currents Id and Iq using this θ. The gate command calculation unit 20 generates a gate command by PWM control so that a three-phase output voltage that matches the voltage command values Vu ^* , Vv ^* , Vw ^* of the three-phase stationary coordinate system obtained by the coordinate converter 19 is obtained. And output to the inverter 1.

Next, the operation in the power failure state (Flg_NoVs = 1) will be described. In a power failure state, the current controller 15 acts so that the DQ axis currents Id and Iq coincide with the DQ axis current commands IdRef and IqRef. First, the voltage Vdc of the filter capacitor 2 is detected by the voltage detector 11 and input to the DC voltage control unit 13. The DC voltage control unit 13 calculates the Q-axis current command IqRef using, for example, PI control so that the DC voltage command Vdc ^* and the detected DC voltage Vdc match.

  Here, KpVdc: proportional gain, KiVdc: integral gain, s: Laplace operator. On the other hand, the D-axis current command IdRef is a predetermined value. Further, currents Iu and Iw flowing through the PMSMs 3 and 4 connected in series, which are loads of the inverter 1, are detected by the current detector 5. The coordinate converter 21 converts the current values Iu and Iw on the three-phase stationary coordinates detected by the current detector 5 into the current values Id and Iq on the DQ axis rotation coordinate system by three-phase / DQ conversion.

The D-axis current command IdRef and the D-axis current Id, the Q-axis current command IqRef and the Q-axis current Iq are input to the current control unit 15 so that each current matches the command value. The DQ axis output voltage commands VdACR and VqACR are calculated by PI control.

Here, KpACR: proportional gain, KiACR: integral gain, s: Laplace operator. The switchers 16 and 17 output the output voltage commands VdACR and VqACR of the current control unit 15 as voltage commands Vd ^* and Vq ^{* in} the case of a power failure (Flg_NoVs = 1).

The axis deviation correction unit 22 receives the D-axis voltage command Vd ^* as an input, and outputs a correction amount θcmp to the inverter output frequency by, for example, PI control so that it becomes zero.

  Here, Kpθcmp: proportional gain, Kiθcmp: integral gain, s: Laplace operator.

The switch 24 outputs the θcmp, and the adder 25 corrects the phase angle reference Θ ^* and outputs it as the phase angle θ. The coordinate converter 19 uses the phase angle θ to convert the DQ axis output voltage commands Vd ^* and Vq ^* into voltage command values Vu ^* , Vv ^* , and Vw ^* in a three-phase stationary coordinate system. The coordinate converter 21 converts the phase currents Iu and Iw detected by the current detector 5 into DQ axis currents Id and Iq using this θ. The gate command calculation unit 20 generates a gate command by PWM control so that a three-phase output voltage that matches the voltage command values Vu ^* , Vv ^* , Vw ^* of the three-phase stationary coordinate system obtained by the coordinate converter 19 is obtained. And output to the inverter 1.

  According to the above configuration, in a sound power state, a stable operation state can be maintained by a so-called V / F control system in which the inverter output frequency ωInv and the output voltage are in a proportional relationship. On the other hand, when a power failure occurs, the input voltage of the rectifier 9 is monitored to determine whether it is a power failure state (Flg_NoVs = 1) or a healthy state (Flg_NoVs = 0). Replace with control. In this case, the Q-axis current is controlled so that the DC voltage to the inverter 1 maintains a predetermined value. On the other hand, the D-axis current is controlled to a predetermined value. Further, the axis deviation correction unit 22 adjusts the phase so that the D-axis voltage becomes zero. As a result, the output voltage has no D-axis component and only the Q-axis component. This guarantees that the inverter output (power) can be controlled not by the D-axis current but by the Q-axis current.

  As described above, in a power failure state, the DC voltage may be maintained at a predetermined value so that the DC voltage does not decrease and operation is not disabled. This can be realized by creating a very weak regenerative state, that is, a state in which minute Iq flows. In this embodiment, the D-axis voltage is set to 0 so that the inverter power can be controlled by this Q-axis current. As a result, the DC voltage is determined even in a power failure state, and the operation can be stably continued without losing sight of the rotation speed or magnet position of the permanent magnet synchronous motors 3 and 4 that are inverter loads. Therefore, it is possible to quickly shift to the steady operation state when power is restored. For this reason, it is possible to reduce as much as possible the state of reduced wind power to the main motor (not shown) to which the blowers 26 and 27 blow cooling air, and the system reliability is deteriorated such as burnout due to the temperature rise of the main motor. Can be avoided.

  (Second Embodiment) The second embodiment of the present invention is characterized in that the D-axis current is maintained at a predetermined value in the first embodiment. Therefore, the functional configuration is the same as in FIG. The first embodiment is a reliable method when only one permanent magnet synchronous motor that is an inverter load is connected. On the other hand, when two permanent magnet synchronous motors are connected, the control of the first embodiment only controls the average magnet positions or speeds of the two units as axis deviation compensation. Therefore, when the two blower loads are in an unbalanced state, the movement of the two rotors becomes vibrational and may eventually diverge. In contrast, these unstable phenomena can be suppressed by maintaining the D-axis current as a positive value as in the present embodiment. That is, when two or more permanent magnet synchronous motors are connected as inverter loads, unbalanced movement between the motors is suppressed, and stable operation can be continued in a power failure state. Therefore, it is possible to improve the system reliability for the same reason as in the first embodiment.

  FIG. 2 shows the result of an experiment carried out by the configuration of the second embodiment of the present invention. For situations such as power interruption time of 5 [sec] to 15 [sec], the operation can be continued by maintaining the DC voltage at a predetermined value without stopping protection even during interruption of power. Then, the power can be quickly shifted to a predetermined rotational speed along with the power recovery. Thereby, in this Embodiment, it has confirmed that the air volume fall of the blower at the time of a power supply interruption could be suppressed as much as possible.

The block diagram of the inverter drive blower control apparatus of the 1st Embodiment and 2nd Embodiment of this invention. The graph which shows the experimental result by the structure of the 2nd Embodiment of this invention.

Explanation of symbols

1 Inverter 2 Filter capacitor 3 Permanent magnet synchronous motor (PMSM)
4 Permanent magnet synchronous motor (PMSM)
DESCRIPTION OF SYMBOLS 5 Current detector 6 Voltage detector 7 Pantograph 8 Wheel 9 Transformer 10 Rectifier 11 Voltage detector 12 Power failure detection part 13 DC voltage control part 15 Current control part 16, 17 Switch 18 Adder 19 Coordinate converter 20 Gate command calculation Unit 21 Coordinate converter 22 Axis deviation correction unit 23 Integrator 24 Switching unit 25 Adder 26, 27 Blower

Claims (1)

A converter that is powered by an AC power source and converts AC to DC;
A filter capacitor for smoothing the voltage on the DC output side of the converter;
An inverter connected to the filter capacitor;
A plurality of permanent magnet synchronous motors connected in series to the inverter to rotate each of the plurality of blowers;
Inverter control means for causing the inverter to output a predetermined output frequency and output voltage;
A power failure detection means for detecting a power failure of the AC power supply;
DC voltage detection means for detecting the DC voltage of the inverter;
Torque control means for controlling the torque of the permanent magnet synchronous motor based on the DC voltage detected by the DC voltage detection means so that the DC voltage matches a predetermined voltage when the power failure detection means detects a power failure ; ,
An inverter drive blower control device comprising: means for causing a current value orthogonal to the output voltage of the inverter to flow positively when the power failure detection means detects a power failure .

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