JP5079074B2 - Inverter device with protection circuit - Google Patents

Description

  The present invention relates to a protection circuit for an inverter device that starts a permanent magnet synchronous motor during high-speed free-running, and protects the circuit element of a DC charging unit and the circuit element of a converted power output unit from damage and controls to start safely. A device is proposed.

  FIG. 2 shows a block diagram of the prior art, and the prior art will be described based on this figure.

  The inverter device 2 includes a DC smoothing unit 12, a DC charging unit 3, a converted power output unit 4, a current detector 14, and a DC voltage detector 15. By closing the electromagnetic contactor 13, the permanent magnet synchronous motor 1 and electric Therefore, it becomes conductive.

  The DC smoothing unit 12 rectifies AC power input from the three-phase AC power supply 11 and outputs DC power. The DC charging unit 3 charges the rectified DC power. The conversion power output unit 4 is composed of a switching element and a free wheel diode connected in parallel, and operates the switching element in response to a switching signal input from the current controller 9 to convert the DC power into an arbitrary power to be permanent. The magnet synchronous motor 1 is supplied.

  The current detector 14 detects the current of each phase of the permanent magnet synchronous motor 1. The DC voltage detector 15 detects the DC voltage of the DC charging unit 3.

  The rotor magnetic pole position and speed estimator 8 uses the current detection value detected by the current detector 14 and the voltage detection value detected by the DC voltage detector 15 to determine the rotor magnetic pole position and rotation speed of the permanent magnet synchronous motor 1. presume.

  When the estimated rotational speed estimated by the rotor magnetic pole position and speed estimator 8 is higher than a predetermined value, the field weakening controller 17 determines the current command value 16, the detected current value, the detected voltage value, and the estimated rotational speed value. Using the rotor pole position estimated value estimated by the rotor pole position and speed estimator 8, field weakening control is performed so as to suppress the terminal voltage of the permanent magnet synchronous motor 1, and the field weakening current command value is set to the current controller 9. Output to. When the estimated rotational speed is lower than the predetermined value, the field weakening controller 17 does not perform the field weakening control, and the field weakening current command value is equal to the current command value 16.

  The current controller 9 generates a voltage command using the field weakening current command value, the current detection value, the voltage detection value, the rotor magnetic pole position estimation value, and the rotation speed estimation value, and converts the voltage command from the voltage command. A switching signal for operating the switching element of the power output unit 4 is output.

  Hereinafter, the starting procedure will be described.

  The electromagnetic contactor 13 is closed to bring the inverter device 2 and the permanent magnet synchronous motor 1 into a conductive state.

  The rotor magnetic pole position and speed estimator 8 uses the current detection value detected by the current detector 14 and the voltage detection value detected by the DC voltage detector 15 to determine the rotor magnetic pole position and rotation speed of the permanent magnet synchronous motor 1. presume.

  As a method for estimating the rotor magnetic pole position and the rotation speed, there are methods as described in Patent Document 1 and Patent Document 2, for example.

  The permanent magnet synchronous motor 1 is free-running at high speed, and the permanent magnet synchronous motor 1 is in a state where the terminal voltage of the permanent magnet synchronous motor 1 is much higher than the voltage of the DC charging unit 3 due to the electromotive force generated by the rotation of the permanent magnet synchronous motor 1. An excessive current flows from 1 to the circuit of the inverter device 2.

  At this time, the excessive current flows through the return diode of the converted power output unit 4, and the circuit element of the converted power output unit 4 or the circuit element of the DC charging unit 3 may be damaged by burning or the like.

JP 2010-11571 A JP 2002-58283 A

  The problem to be solved is that when the permanent magnet synchronous motor is in a high speed free run and the terminal voltage of the permanent magnet synchronous motor is extremely higher than the DC charging unit, the electromagnetic contactor is closed and the permanent magnet synchronous motor and the inverter device are When the conductive state is established, there is a risk that the circuit element of the converted power output unit or the circuit element of the DC charging unit may be damaged due to an excessive current flowing.

  According to the first aspect of the present invention, a DC smoothing unit, a DC charging unit, a conversion power output unit composed of a switching element and a reflux diode connected in parallel, a current detector, and a DC voltage detector are included. The permanent magnet synchronous motor is electrically connected to the permanent magnet synchronous motor by closing the electromagnetic contactor, and the permanent magnet synchronization is performed using the current detection value detected by the current detector and the voltage detection value detected by the DC voltage detector. A rotor magnetic pole position and speed estimator for estimating the rotor magnetic pole position and the rotational speed of the electric motor are provided, and the current command value, the current detection value, the voltage detection value, the rotor magnetic pole position and the speed estimator are estimated. A field weakening controller that performs field weakening control using the rotor magnetic pole position estimated value and the rotational speed estimated value, and the current detection value, the voltage detection value, the rotor magnetic pole position estimation value, and the In an inverter device having a current controller that outputs a switching signal for operating a switching element of the converted power output unit using a rotation speed estimated value and a field weakening control current command value output from the field weakening controller, the DC charging unit, When a resistor is connected in series to the circuit on the high potential side of the circuit through which the direct current flows between the converted power output units and the switch is turned on, a circuit in which a direct current from the converted power output unit to the direct current charging unit flows is established. A protection circuit comprising: a transistor connected in parallel with the resistor; and a diode connected in parallel with the resistor that operates in a forward direction from the DC charging unit toward the converted power output unit. With inverter device.

  According to the invention of claim 2, the permanent magnet synchronous motor is in a high speed free run, and the terminal voltage of the permanent magnet synchronous motor is extremely higher than the DC charging unit due to the electromotive force generated by the rotation of the permanent magnet synchronous motor. In this case, after the transistor is turned off, the electromagnetic contactor is closed to be electrically connected to the permanent magnet synchronous motor, and the rotor magnetic pole position and speed estimator are configured using the current detection value and the voltage detection value. The rotor magnetic pole position estimated value and the rotational speed estimated value are calculated, and then the current command value, the current detected value, the voltage detected value, the rotor magnetic pole position estimated value, and the rotational speed estimated value are used. The field weakening controller starts the field weakening control, and then turns on the transistor. The current detection value, the voltage detection value, and the field weakening controller The protection circuit according to claim 1, wherein the current controller outputs a switching signal by using a weak field current command value to be applied and starts operation of the permanent magnet synchronous motor. Inverter device.

  In order to solve the above-mentioned problem, the present invention connects a resistor in series to a circuit on the high potential side of a circuit through which a direct current flows between a direct current charging unit and a converted power output unit, and when the switch is turned on, the converted power output A transistor that establishes a circuit through which a direct current flowing from the direct current to the direct current charging unit flows is connected in parallel to the resistor, and a diode that operates in a forward direction from the direct current charging unit to the converted power output unit is used as the resistance A circuit connected in parallel is provided.

  The present invention has an advantage that even if the permanent magnet synchronous motor is in a high-speed free run, the circuit of the inverter device is prevented from being damaged and can be started safely.

It is explanatory drawing which showed one implementation method of this invention. Example 1 It is explanatory drawing which showed the prior art.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a block diagram of an embodiment of the apparatus of the present invention. 2 differs from the prior art of FIG. 2 in that the resistor 5 is connected in series to the high potential side of the DC circuit unit, and the switch 5 is connected in parallel to the resistor 5 and the converted power output unit 4 goes to the DC charging unit 3 A transistor 6 that establishes a path through which a direct current flows, a diode 7 that is connected in parallel to the resistor 5 and that operates in a forward direction from the direct current charging unit 3 to the converted power output unit 4, and a signal that operates a switch of the transistor 6 Is a protection circuit 10 that outputs.

  Hereinafter, the operation at the time of starting will be described.

  The magnetic contactor 13 is turned on in a state where the transistor 6 is turned off and all the switching elements of the converted power output unit 4 are turned off.

  When the permanent magnet synchronous motor 1 is in a high speed free run and the terminal voltage of the permanent magnet synchronous motor 1 is higher than the voltage of the DC charging unit 3, current flows from the terminal of the permanent magnet synchronous motor 1 to the resistor 5 and is converted by a voltage drop. The current flowing to the power output unit 4 and the DC charging unit 3 is limited. This prevents an excessive current from flowing through the circuit element of the converted power output unit 4 and the circuit element of the DC charging unit 3.

  The rotor magnetic pole position and speed estimator 8 uses the current detection value detected by the current detector 14 and the voltage detection value detected by the DC voltage detector 15 to determine the rotor magnetic pole position and rotation speed of the permanent magnet synchronous motor 1. presume.

  When the estimated rotational speed estimated by the rotor magnetic pole position and speed estimator 8 is higher than a predetermined value, the field weakening controller 17 determines the current command value 16, the detected current value, the detected voltage value, and the estimated rotational speed value. The field weakening control is performed using the rotor magnetic pole position and the rotational speed estimated value estimated by the speed estimator 8, and the field weakening current command value is output to the current controller 9.

  The terminal voltage of the permanent magnet synchronous motor 1 is suppressed by the field weakening control, and the protection circuit 10 turns on the transistor 6 when the detected current value becomes smaller than a predetermined value.

  The current controller 9 generates a voltage command using the current detection value, the voltage detection value, the rotor magnetic pole position estimation value, the rotation speed estimation value, and the field weakening current command value, and converts the voltage command from the voltage command. A switching signal for operating the switching element of the power output unit 4 is output.

  Therefore, the present invention prevents the circuit element of the converted power output unit 4 and the circuit element of the DC charging unit 3 from being damaged by an excessive current when starting the permanent magnet synchronous motor 1 during the high speed free run. Can be solved.

  When starting the permanent magnet synchronous motor during the high speed free run, it is possible to easily prevent the circuit of the inverter device from being damaged.

DESCRIPTION OF SYMBOLS 1 Permanent magnet synchronous motor 2 Inverter apparatus 21 Inverter apparatus 3 DC charging part 4 Conversion electric power output part 5 Resistance 6 Transistor 7 Diode 8 Rotor magnetic pole position and speed estimator 9 Current controller 10 Protection apparatus 11 Three-phase alternating current power supply 12 DC smoothing Part 13 Magnetic contactor 14 Current detector 15 DC voltage detector 16 Current command value 17 Field weakening controller

Claims (2)

  Consists of a DC smoothing unit, a DC charging unit, a conversion power output unit composed of a switching element and a reflux diode connected in parallel, a current detector, and a DC voltage detector, and by closing the electromagnetic contactor A rotor magnetic pole position and a rotational speed of the permanent magnet synchronous motor that are electrically connected to the permanent magnet synchronous motor and that use the current detection value detected by the current detector and the voltage detection value detected by the DC voltage detector. A rotor magnetic pole position and speed estimator for estimating the current command value, the current detection value, the voltage detection value, the rotor magnetic pole position and the speed estimator. A field-weakening controller that performs field-weakening control using the estimated value, the current detection value, the voltage detection value, the rotor magnetic pole position estimation value, the rotation speed estimation value, and the weakening In an inverter device having a current controller that outputs a switching signal for operating a switching element of the converted power output unit using a field weakening control current command value output by the magnetic controller, the DC charging unit and the converted power output unit A resistor is connected in series to a circuit on the high potential side of a circuit through which a direct current flows between, and when the switch is turned on, a transistor in which a circuit through which a direct current flows from the converted power output unit to the direct current charging unit is established as the resistor An inverter device with a protection circuit, comprising: a circuit connected in parallel, and a diode operating in a forward direction from the DC charging unit toward the converted power output unit, and connected in parallel to the resistor. The permanent magnet synchronous motor is in a high speed free run, and the terminal voltage of the permanent magnet synchronous motor is extremely higher than the DC charging unit due to the electromotive force generated by the rotation of the permanent magnet synchronous motor. The electromagnetic contactor is closed and is electrically connected to the permanent magnet synchronous motor, and the rotor magnetic pole position and speed estimator are used to detect the rotor magnetic pole position estimated value and the voltage detected value using the detected current value and the detected voltage value. The rotation speed estimation value is calculated, and then the field weakening controller starts the field weakening control using the current command value, the current detection value, the voltage detection value, the rotor magnetic pole position estimation value, and the rotation speed estimation value. Then, the transistor is turned on, and the current detection value, the voltage detection value, and the field weakening current command output by the field weakening controller Protection circuit with an inverter apparatus according to claim 1, wherein the current controller is characterized by including a function to start operation of outputting the switching signal the permanent magnet synchronous motor used.

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