JP2012228010A - Motor control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem when charging a bootstrap circuit of a motor control apparatus in which: it takes more charging time if trying to suppress circuit loss; and the circuit loss increases or a power supply requires more capacity if trying to shorten the charging time.SOLUTION: When charging a bootstrap circuit 106, each phase is gradually charged at a timing lagged by predetermined time and a motor 101 is used as a restriction resistor during charging of a first phase to charge other phases, so that inrush current can be prevented. Therefore, it is possible to downsize a circuit, and decrease charging time while suppressing circuit loss.

Description

  The present invention relates to a control device for an electric motor such as a brushless DC motor which performs rotation speed control by an inverter circuit configuration having a bootstrap circuit and is used as a power source for home use and industrial use.

  Conventionally, in this type of motor control device, the initial charging of the bootstrap capacitor is performed simultaneously to suppress the inrush current, but one that performs duty control (for example, see Patent Document 1) or one phase at a time. A device that performs a charging process (see, for example, Patent Document 2) is known.

  FIG. 4 is an example of a circuit diagram of a control device for an electric motor that performs rotational speed control by an inverter circuit configuration having a conventional bootstrap circuit.

  The rectifier circuit 402 converts an AC voltage of the AC input 401 into a DC voltage, and has a configuration in which diodes 402a to 402d and capacitors 402e to 402f are connected. Here, FIG. 4 shows a voltage doubler rectifier circuit as an example, but the rectifier circuit may be a full-wave rectifier circuit.

  The power supply circuit 403 generates a main power supply (for example, DC + 15V) necessary for the control side based on the DC voltage rectified by the rectifier circuit 402.

  In the inverter circuit 404, two semiconductor switches 404a to 404f (for example, IGBT, MOS-FET, etc.) are connected to each other in a totem pole type, and are connected for three phases of U, V, and W phases. Further, diodes 404g to 404l are connected to the semiconductor switches 404a to 404f, respectively. In addition, when using MOS-FET for the semiconductor switches 404a-404f, each diode 404g-404l becomes unnecessary.

  The inverter circuit 404 is connected to drive circuits 404U +, 404V +, 404W +, 404U−, 404V−, 404W− that can individually turn on / off the semiconductor switches 404a to 404f.

  In FIG. 4, the drive circuit on the electric circuit diagram side and the drive circuit on the block diagram side are the same, and each is shown by a reference numeral.

  Further, the drive circuits 404U + and 404U−, the drive circuits 404V + and 404V−, and the drive circuits 404W + and 404W− constitute one set of circuits (not shown).

  The bootstrap circuit 405 includes diodes 405d, 405e, 405f having a high withstand voltage (for example, 600V), resistors 405a, 405b, 405c and capacitors 405d, 405e, 405f connected in series with the diodes 405d, 405e, 405f. The

  Next, the basic operation of the bootstrap circuit 405 will be described below.

For convenience of explanation, for example, a circuit constituted by semiconductor switches 404a and 404d, diodes 404g and 404j, drive circuits 404U + and 404U−, a resistor 405a, a diode 405d, and a capacitor 405g is referred to as a U-phase circuit. Similarly, a circuit constituted by the semiconductor switches 404b and 404e, the diodes 404h and 404k, the drive circuits 404V + and 404V−, the resistor 405b, the diode 405e, and the capacitor 405h is converted into a V-phase circuit, the semiconductor switches 404c and 404f, the diodes 404i and 404l, A circuit constituted by the drive circuits 404W + and 404W−, the resistor 405c, the diode 405f, and the capacitor 405i is referred to as a W-phase circuit.

  For example, in the U-phase circuit, when the semiconductor switch 404a is in the off state and the semiconductor switch 404d is in the on state, the potential at the connection point between the emitter side of the semiconductor switch 404a and the collector side of the semiconductor switch 404d is A value near the ground potential in the circuit 404 is obtained.

  At this time, the anode side potential of the diode 405d is a positive potential with respect to the ground in the inverter circuit 404 (for example, DC + 15V if the output voltage of the power supply circuit 403 is DC + 15V), and the capacitor 405g is connected via the resistor 405a and the diode 405d. Current flows, and the charge is charged. The charge is charged in the capacitor 405g only until the semiconductor switch 404d is in the ON state (however, until the charge is satisfied), and a voltage corresponding to the charge amount is generated at both ends of the capacitor 405g.

  Even when the semiconductor switch 404d is turned off, the electric charge of the capacitor 405g is gradually discharged, but is maintained for a certain period of time, and a voltage corresponding to the amount of electric charge in the capacitor 405g is driven until the electric charge is discharged. It can be used for power supply to the circuit 404U + and the semiconductor switch 404a.

  However, if the semiconductor switch 404d is turned off and the drive circuit 404U + and the semiconductor switch 404a are continuously driven, the amount of charge in the capacitor 405g gradually decreases.

  That is, in the bootstrap circuit 405, the low-voltage side semiconductor switches 404d, 404e, and 404f among the semiconductor switches connected in a pair of totem poles are in an on state, and the high-voltage side semiconductor switches 404a, When 404b and 404c are off, the capacitors 405g, 405h, and 405i are charged. The charged charges are used to drive the high-voltage side semiconductor switches 404a, 404b, and 404c when the low-voltage side semiconductor switches 404d, 404e, and 404f are in an off state.

  In the electric motor 406, the semiconductor switches 404a to 404f are individually turned on / off, whereby a current flows through the electric motor 406 and an internal rotor (not shown) rotates.

  The inverter control means 407 includes commutation means 408, chopping signal generation means 409, synthesis means 410, and charge pulse generation means 411. Based on the signal from the inverter control means 407, the semiconductor switches 404a to 404 404f can be individually turned on / off.

  The position detection means 412 detects the rotational position of the rotor of the electric motor 406, generates a rotation pulse, and outputs it to the inverter control means 407.

  The commutation means 408 generates commutation pulses for commutating the semiconductor switches 404a to 404f of the inverter circuit 404 from the output of the position detection means 412 and outputs the commutation pulses to the drive circuits 404U−, 404V−, 404W−, and the combining means 410. .

  The chopping signal generation means 409 generates waveforms with different on / off ratios at a constant frequency in order to make the rotation speed of the electric motor 406 variable.

  The synthesizer 410 synthesizes the commutation pulse output from the commutator 408 and the chopping signal output from the chopping signal generator 409, and outputs a combined signal to the drive circuits 404U +, 404V +, 404W +.

  The charge pulse generator 411 outputs charge pulses for charging the capacitors 405g, 405h, and 405i of the bootstrap circuit 405 to the drive circuits 404U−, 404V−, 404W−, and the commutator 408.

  The operation mode determination unit 413 that issues an operation / stop command for the electric motor 406 outputs a signal to the charge pulse generation unit 411 and the synthesis unit 410.

  FIG. 5 shows a charging process described in Patent Document 1, in which capacitors 405g, 405h, and 405i are simultaneously charged with respect to T501 to T502 that are charging sections.

  That is, at T501, the drive circuits 404U-, 404V-, 404W- are simultaneously turned on by the duty, and charging to the capacitors 405g, 405h, 405i of the bootstrap circuit 405 is started simultaneously.

  At T502, charging of all the capacitors 405g, 405h, and 405i is completed, and the motor 406 is rotated from T503.

  At this time, although the effective value of the current flowing through the rectifier circuit 402 is suppressed, the instantaneous inrush current is the sum of the inrush current values into the capacitors 405g, 405h, and 405i of the bootstrap circuit 405. It becomes three times the inrush current value when charging 405h and 405i individually. In addition, the smaller the values of the resistors 405a, 405b, and 405c of the bootstrap circuit 405, the larger the fluctuation of the instantaneous current value becomes.

  In addition, since charging to the capacitors 405g, 405h, and 405i is performed only during the duty ON period, the charging time varies depending on the duty ratio. For this reason, if the duty off period to the drive circuits 404U−, 404V−, and 404W− is lengthened in order to suppress the effective value, the charging time for the capacitors 405g, 405h, and 405i becomes long.

  FIG. 6 shows a charging process described in Patent Document 2, in which capacitors 405g, 405h, and 405i are sequentially charged with respect to T601 to T604 that are charging sections.

  That is, at T601, the drive circuit 404V- is turned on and charging of the capacitor 405h is started.

  At this time, the inrush current corresponds to one circuit of the bootstrap circuit 405, and becomes a current value flowing through the resistor 405b and the capacitor 405h.

  Since the capacitor 405h is completed at T602, the drive circuit 404V− is turned off, and then the drive circuit 404W− is turned on to start charging the capacitor 405i.

  At this time, the inrush current corresponds to one circuit of the bootstrap circuit 405, and becomes a current value flowing through the resistor 405c and the capacitor 405i.

  Furthermore, since the capacitor 405i is completed at T603, the drive circuit 404W- is turned off, and then the drive circuit 404U- is turned on to start charging the capacitor 405g.

  At this time, the inrush current is equivalent to one circuit of the bootstrap circuit 405 and becomes a current value flowing through the resistor 405a and the capacitor 405g.

  Then, charging of all the capacitors 405g, 405h, and 405i is completed at T604, and the motor 406 is rotated from T605.

  Therefore, the inrush current when charging the capacitors 405g, 405h, and 405i of the bootstrap circuit 405 can be suppressed to the current value of one circuit of the bootstrap circuit 405, but the charging time is simply three times as long as the simultaneous charging time. Is required.

Japanese Patent No. 3663874 Japanese Patent No. 3775921

  However, in the conventional bootstrap circuit driving method, for example, in the case of duty control by simultaneous charging, the instantaneous inrush current is the sum of the U phase, the V phase, and the W phase. In addition, when the U phase, the V phase, and the W phase are energized in order, there is a problem that it takes a considerable time to complete charging.

  The present invention solves the above-described conventional problems, and charging the bootstrap circuit is performed by shifting the phases of the U phase, V phase, and W phase in stages, thereby minimizing circuit loss. It is an object of the present invention to provide an electric motor control device that is more user-friendly by limiting the time until completion of charging.

  The motor control device of the present invention includes a motor having a three-phase armature winding and a rotor, a rectifier circuit that converts AC input into DC, a power supply circuit that supplies control power in the operation control device, and an inverter Three sets of high-potential side switching elements connected to the output of the circuit and the rectifier circuit constituting the inverter circuit and connected in a totem pole type with two sets corresponding to three-phase armature windings and a low potential To obtain electric power for driving each semiconductor switch on the high voltage side among the semiconductor switches connected to the totem pole type, a semiconductor switch composed of a side switching element, a driving circuit for driving each semiconductor switch A bootstrap circuit, inverter control means for generating a signal for on / off control of the semiconductor switch, and detecting the position of the rotor of the motor A position detecting means for generating a commutation pulse; a commutation means incorporated in the inverter control means for determining the operation of the semiconductor switch of the inverter circuit based on the output of the position detecting means; and the rotational speed of the electric motor. Chopping signal generation means for generating a chopping signal for making variable, operation mode determination means for determining operation / stop of the electric motor, output of the commutation means, output of the chopping signal generation means, and determination of the operation mode A combination means for combining the outputs of the means; and an initial charge delay means for charging the bootstrap circuit in stages at intervals of a predetermined time.

According to the present invention, with respect to charging to the bootstrap circuit before driving the motor, charging to each phase is performed in a stepwise manner by shifting the charging to each phase, thereby limiting the motor during the first phase charging. Charging to the other phase via can be used. Therefore, even if the three phases are energized simultaneously after a predetermined time, the inrush current can be suppressed and the circuit loss can be suppressed. As a result, the circuit can be downsized and the charging time can be shortened at the same time.

  Further, the electric current detection means can detect the connection abnormality without moving the electric motor by utilizing the fact that the charging current waveform changes depending on whether the electric motor is connected or not when charging the bootstrap circuit.

  The motor control device according to the present invention is capable of detecting a connection abnormality without moving the motor depending on whether or not the motor is connected while suppressing the inrush current, and therefore provides a motor controller with higher safety. Can do.

1 is a circuit diagram of an electric motor control device according to Embodiment 1 of the present invention. Charging voltage waveform diagram formed by the motor control device in the first embodiment Current waveform diagram by charging voltage of electric motor control device in embodiment 1 Circuit diagram of motor control device in conventional example Charging voltage waveform diagram by motor control device in conventional example Charging voltage waveform diagram by motor control device in different conventional examples

  A first invention includes an electric motor having a three-phase armature winding and a rotor, a rectifier circuit that converts AC input into DC, a power supply circuit that supplies control power in the operation control device, an inverter circuit, Three sets of high-potential side switching elements and low-potential side switching connected to the output of the rectifier circuit that constitutes the inverter circuit and connected in a totem pole type with two sets corresponding to three-phase armature windings A semiconductor switch composed of elements, a drive circuit for driving each semiconductor switch, a bootstrap circuit for obtaining power for driving each semiconductor switch on the high voltage side of the semiconductor switches, and the semiconductor switch Inverter control means for generating a signal for controlling on / off of the motor, position detection means for detecting the position of the rotor of the electric motor and generating a rotation pulse, Commutation means that is incorporated in the inverter control means and determines the operation of the semiconductor switch of the inverter circuit based on the output of the position detection means, and chopping that generates a chopping signal for making the rotation speed of the motor variable A signal generation means, an operation mode determination means for determining operation / stop of the electric motor, a synthesis means for combining the output of the commutation means, the output of the chopping signal generation means, and the output of the operation mode determination means, There is provided an initial charge delay means for charging the bootstrap circuit in a stepwise manner with each phase being spaced by a predetermined time interval.

  In this way, at the time of the first phase charging, by using the charging to the other phase through the electric motor as a limiting resistor, the inrush current can be suppressed even if the three phases are energized simultaneously after a predetermined time. As a result, the circuit loss can be suppressed, so that the circuit can be downsized and the charging time can be shortened at the same time.

  According to a second aspect of the present invention, in the first aspect of the present invention, current detection means is provided, and the connection of the motor is confirmed when the bootstrap circuit is charged by the initial charge delay means.

Accordingly, it is possible to detect a connection abnormality without moving the motor by utilizing the fact that the charging current waveform changes depending on whether or not the motor is connected when charging the bootstrap circuit.

(Embodiment 1)
FIG. 1 is a circuit diagram of a motor control device according to Embodiment 1 of the present invention. FIG. 2 is a charge voltage waveform diagram of the motor control device according to the first embodiment. FIG. 3 is a current waveform diagram according to the charging voltage in the first embodiment.

  In FIG. 1, an electric motor 101 has an internal rotor (not shown) that rotates when a current flows.

  The rectifier circuit 103 converts the AC voltage of the AC input 102 into a DC voltage, and has a configuration in which diodes 103a to 103d and capacitors 103e to 103f are connected. Here, FIG. 1 shows a voltage doubler rectifier circuit as an example, but the rectifier circuit may be a full-wave rectifier circuit.

  The power supply circuit 104 generates a main power supply (for example, DC + 12V, DC + 15V, etc.) necessary for the control side based on the direct current voltage rectified by the rectifier circuit 103.

  In the inverter circuit 105, two semiconductor switches 105a to 105f (for example, IGBT, MOS-FET, etc.) are connected in a totem pole type as a set, and three phases of U, V, and W phases are connected. Further, diodes 105g to 105l are connected to the semiconductor switches 105a to 105f, respectively. In addition, when using MOS-FET for the semiconductor switches 105a-105f, each diode 105g-105l becomes unnecessary.

  The inverter circuit 105 is connected to drive circuits 105U +, 105V +, 105W +, 105U−, 105V−, and 105W− that can individually turn on / off the semiconductor switches 105a to 105f.

  In FIG. 1, the drive circuit on the electric circuit diagram side and the drive circuit on the block diagram side are the same, and each is shown by a reference numeral.

  Further, the drive circuits 105U + and 105U−, the drive circuits 105V + and 105V−, and the drive circuits 105W + and 105W− constitute one set of circuits (not shown).

  The bootstrap circuit 106 includes diodes 106d, 106e, 106f having high withstand voltage (for example, 600V), resistors 106a, 106b, 106c connected in series with the diodes 106d, 106e, 106f, and capacitors 106d, 106e, 106f. The

  Next, the basic operation of the bootstrap circuit 106 will be described below.

For convenience of explanation, for example, a circuit constituted by semiconductor switches 105a and 105d, diodes 105g and 105j, drive circuits 105U + and 105U−, a resistor 106a, a diode 106d, and a capacitor 106g is referred to as a U-phase circuit. Similarly, a circuit constituted by semiconductor switches 105b and 105e, diodes 105h and 105k, drive circuits 105V + and 105V-, resistor 106b, diode 106e, and capacitor 106h is a V-phase circuit, semiconductor switches 105c and 105f, diodes 105i and 105l, Drive circuits 105W + and 105W-, resistor 106c, diode 106f, capacitor 1
A circuit configured by 06i is referred to as a W-phase circuit.

  For example, in the U-phase circuit, when the semiconductor switch 105a is turned off and the semiconductor switch 105d is turned on, the potential at the connection point between the emitter side of the semiconductor switch 105a and the collector side of the semiconductor switch 105d is It becomes a value near the ground potential in the circuit 105.

  At this time, the anode side potential of the diode 106d becomes a positive potential with respect to the ground in the inverter circuit 105 (for example, DC + 15V when the output voltage of the power supply circuit 104 is DC + 15V), and the capacitor 106g is connected via the resistor 106a and the diode 106d. Current flows, and the charge is charged. Then, only when the semiconductor switch 105d is in the ON state, the capacitor 106g is charged (but until the charge is satisfied), and a voltage corresponding to the amount of charge is generated across the capacitor 106g.

  Even if the semiconductor switch 105d is turned off, the electric charge of the capacitor 106g is gradually discharged, but is maintained for a certain period of time, and a voltage corresponding to the amount of charge in the capacitor 106g is driven until the electric charge is discharged. It can be used for power supply to the circuit 105U + and the semiconductor switch 105a.

  However, when the semiconductor switch 105d is turned off and the drive circuit 105U + and the semiconductor switch 105a are continuously driven, the amount of charge in the capacitor 106g gradually decreases.

  That is, in the bootstrap circuit 106, the semiconductor switches 105d, 105e, and 105f on the low voltage side among the semiconductor switches connected in a pair of totem poles are in the on state, and the semiconductor switches 105a, When the capacitors 105b and 105c are in the off state, the capacitors 106g, 106h, and 106i are charged. The charged charges are used to drive the high-voltage side semiconductor switches 105a, 105b, and 105c when the low-voltage side semiconductor switches 105d, 105e, and 105f are in an off state.

  The power supply line is provided with a current detection means 107 for detecting a current value flowing through the power supply circuit 104 via the electric motor 101. The current detection means 107 only needs to be able to detect the value of the current flowing through the power supply circuit 104, and can be substituted not only by a current transformer but also by voltage detection using a resistance voltage divider or the like, and by an analog circuit using an operational amplifier and a comparator. It may be configured.

  The inverter control means 108 includes commutation means 109, chopping signal generation means 110, synthesis means 111, and initial charge delay means 112.

  The commutation means 109 generates a commutation pulse for commutating the semiconductor switches 105a to 105f of the inverter circuit 105 from the output of the position detection means 113, and outputs the commutation pulse to the drive circuits 105U−, 105V−, 105W−, and the combining means 111. .

  The chopping signal generating means 110 creates waveforms with different on / off ratios at a constant frequency in order to make the rotation speed of the electric motor 101 variable.

  The synthesizing unit 111 synthesizes the commutation pulse output from the commutation unit 109 and the chopping signal output from the chopping signal generation unit 110, and outputs the combined signal to the drive circuits 105U +, 105V +, and 105W +.

The initial charging delay means 112 is configured such that each of the capacitors 106g, 106h, and 106i is predetermined when charging the capacitors 106g, 106h, and 106i of the bootstrap circuit 106 when the operation is started after the motor 101 is stopped. The drive circuits 105U-, 105V-, and 105W- are output with a predetermined time shift so as to start charging with a time shift.

  When the electric motor 101 is in operation, the capacitors 106g, 106h, and 106i of the bootstrap circuit 106 are charged at the same time by the output from the commutation means 109. This is because the outputs of the drive circuits 105U−, 105V−, and 105W− are required for charging the capacitors 106g, 106h, and 106i of the bootstrap circuit 106, respectively. The output from the commutation means 109 is always two-phase + and − outputs (for example, 105U + and 105V−), which are different from each other in the U-phase circuit, V-phase circuit, and W-phase circuit. This is because the capacitors 106g, 106h, and 106i can be charged.

  The position detection means 113 detects the rotational position of the rotor of the electric motor 101, generates a rotation pulse, and outputs it to the inverter control means 108.

  The operation mode determination unit 114 that issues an operation / stop command for the electric motor 101 outputs a signal to the initial charging delay unit 112 and the combining unit 111.

  Next, the charging operation of the motor control device will be described with reference to FIG.

  In FIG. 2, the drive circuit 105U- is turned on in order to start charging the capacitor 106g of the U-phase circuit in the charging section T201. At this time, when the electric motor 101 is connected, charging of the capacitors 106h and 106i is started via the electric motor 101 simultaneously with the start of charging of the capacitor 106g of the U-phase circuit.

  For the inrush current, the current value for the resistor 106a is added to the capacitor 106g of the U-phase circuit, and the equivalent series resistance of the motor 101 between the V-phase and U-phase is added to the resistor 106b for the capacitor 106h of the V-phase circuit. The sum of the current value for the combined resistance and the current value for the combined resistance obtained by adding the equivalent series resistance of the motor 101 between the W phase and the U phase to the resistor 106c flows to the capacitor 106i of the W phase circuit.

  Since the equivalent series resistance value of the electric motor 101 is generally several Ω, the current value can be restricted, and in addition, the inductance component of the electric motor 101 has a property that it is difficult for current to flow at the time of rushing. When the charging of the capacitor 106g of the U-phase circuit is started, the charging of the capacitor 106h of the V-phase circuit and the capacitor 106i of the W-phase circuit can also be started.

  The charging section T202 is when the capacitor 106g of the U-phase circuit has been charged to some extent, and the drive circuit 105V- is turned on in order to speed up the charging of the capacitor 106h of the V-phase circuit without passing through the motor 101. At this time, since a certain amount of charge has already accumulated in the capacitor 106h, the inrush current value is also small.

  The charging period T203 is when the capacitor 106h of the V-phase circuit has been charged to some extent. In order to speed up the charging of the capacitor 106i of the W-phase circuit without passing through the motor 101, the drive circuit 105W- is turned on. The drive circuits 105U−, 105V−, and 105W− are all turned on to complete the charging of the capacitors 106g, 106h, and 106i. At this time, since a certain amount of charge has already accumulated in the capacitor 106i, the inrush current value is also small.

  In the charging section T204, the charging of the capacitors 106g, 106h, and 106i is completed. In the section T205, the drive circuit 105U +, 105V +, 105W +, 105U−, 105V−, 105W− is controlled by the inverter control unit 108, and the electric motor 101 The motor is rotated.

  Next, the charging operation to the capacitors 106g, 106h, and 106i will be described with reference to FIG.

  In the charging sections T201 to T204 described with reference to FIG. 2, when the motor 101 is connected, disconnected, or disconnected, the current value detected by the current detection unit 107 is different.

  That is, when the electric motor 101 is connected, as described with reference to FIG. 2, the capacitor 106g of the U-phase circuit is started to be charged in the charging period T201, and at the same time, the capacitors 106h and 106i are charged via the electric motor 101. Be started. Therefore, the current value detected by the current detection unit 107 is not as large as the charging period T201 in the charging periods T202 and T203, and is a small value.

  However, when the electric motor 101 is not connected or disconnected, even if the capacitor 106g of the U-phase circuit is started to be charged in the charging section T201, the charging of the capacitors 106h and 106i is not started because the electric motor 101 is not interposed.

  In this case, the capacitors 106h and 106i are charged in charging sections T202 and T203, respectively.

  The inrush current value is the current value for the resistor 106a in the charging period T201, the inrush current value for the resistor 106b is added in the charging period T202, and the inrush current value for the resistor 106c is added in the charging period T203. Each time the dynamic circuits 105U−, 105V−, and 105W− are turned on, the inrush current value applied to the capacitor for one circuit of the bootstrap circuit 106 is detected.

  Therefore, the case where the electric motor 101 is connected and the case where the electric motor 101 is not connected or disconnected can be detected between the charging sections T201 to T204.

  As described above, as in the charging sections T201 to T203, in the charging of the capacitors 106g, 106h, and 106i, energization through the electric motor 101 is performed, and the characteristics of the inductance component and the equivalent series resistance component are utilized to drive the drive circuit 105U−, Charging can be performed by sequentially energizing 105V− and 105W− with a predetermined time shift. Moreover, the drive circuits 105U−, 105V−, and 105W− are simultaneously turned on, and are sufficiently smaller than the inrush current when the capacitors 106g, 106h, and 106i are charged, and the drive circuits 105U−, 105V−, and 105W Charging can be performed in a sufficiently early time compared to individually turning on the capacitors 106g, 106h, and 106i.

  Further, since the current can be suppressed by utilizing the characteristics of the electric motor 101, the values of the resistors 106a, 106b, and 106c can be further reduced, the circuit loss can be reduced, and the load on the power supply circuit 104 can be reduced. It is also possible to reduce the circuit size.

Further, for charging the capacitors 106g, 106h, and 106i, the inverter control means 108 does not need to control the drive circuits 105U−, 105V−, and 105W− by duty, and reduces noise and noise due to duty output. be able to.

  In addition, since the input waveform to the current detection means 107 is different when the capacitors 106g, 106h, and 106i are charged depending on whether the motor 101 is connected, disconnected, or disconnected, a connection failure of the motor 101 is detected before the motor 101 is driven. Can improve safety.

  In the first embodiment, the driving circuits 105U−, 105V−, and 105W− are turned on in this order for charging the capacitors 106g, 106h, and 106i of the bootstrap circuit 106, but the driving circuits 105U−, The turn-on order of 105V− and 105W− is not limited to this.

  As described above, the electric motor control device according to the present invention can obtain the same effect as long as it uses an electric motor. Therefore, household electric appliances such as an air conditioner and a refrigerator, electric vehicles, etc. It can be applied to other uses.

DESCRIPTION OF SYMBOLS 101 Electric motor 103 Rectifier circuit 104 Power supply circuit 105 Inverter circuit 105a Semiconductor switch 105b Semiconductor switch 105c Semiconductor switch 105d Semiconductor switch 105e Semiconductor switch 105f Semiconductor switch 105U + Driving circuit 105V + Driving circuit 105W + Driving circuit 105U- Driving circuit 105V- Driving circuit 105W- Driving circuit 106 bootstrap circuit 107 current detection means 108 inverter control means 109 commutation means 110 chopping signal generation means 111 synthesis means 112 initial charge delay means 113 position detection means 114 operation mode determination means

Claims (2)

An electric motor having a three-phase armature winding and a rotor, a rectifier circuit that converts AC input into DC, a power supply circuit that supplies control power in the operation control device, an inverter circuit, and the inverter circuit Consists of three sets of high-potential side switching elements and low-potential side switching elements that are connected to the output of the rectifier circuit and that are connected in a totem pole shape with one set corresponding to three-phase armature windings Semiconductor switch, drive circuit for driving each semiconductor switch, bootstrap circuit for obtaining power for driving each semiconductor switch on the high voltage side of the semiconductor switch, and on / off control of the semiconductor switch Inverter control means for generating a signal, position detection means for detecting a position of a rotor of the electric motor and generating a rotation pulse, and the inverter control Commutating means for determining the operation of the semiconductor switch of the inverter circuit based on the output of the position detecting means, and chopping signal generation for generating a chopping signal for making the rotation speed of the motor variable Means for determining operation / stop of the motor, combining means for combining the output of the commutation means, the output of the chopping signal generation means, and the output of the operation mode determination means, and the bootstrap. An electric motor control device comprising an initial charge delay means for charging a circuit in stages with a predetermined time interval for each phase. The motor control device according to claim 1, further comprising a current detection unit, wherein connection confirmation of the motor is performed when the bootstrap circuit is charged by the initial charge delay unit.