JP7014598B2 - Inverter device, booster circuit control method and program - Google Patents

Description

The present invention relates to an inverter device, a booster circuit control method and a program.

In relation to the power supply to the motor, the DC power supply device described in Patent Document 1 has a full-wave rectification mode and a boost mode in which a voltage twice the voltage obtained by the full-wave rectification is generated and supplied to the motor. To supply voltage to the motor. Further, in the DC power supply device described in Patent Document 1, the on-duty ratio of the two switching elements for boosting is gradually increased in order to reduce the inrush current when switching between the full-wave rectification mode and the boosting mode. Let me.

Republished WO2015 / 056721

In supplying power to the motor, it is important not only to reduce the inrush current but also to take measures against the step-out of the motor. It is preferable that measures against motor step-out can be taken by a relatively simple method.

The present invention provides an inverter device, a booster circuit control method, and a program that can take measures against motor step-out by a relatively simple method.

According to the first aspect of the present invention, in the inverter device, with respect to the inverter circuit that supplies power to the motor, the double-pressure DC voltage corresponding to twice the single-pressure DC voltage is changed from the single-pressure DC voltage. The rectifying circuit is a booster circuit that supplies DC voltage within the range up to, and is located at a position connecting the positive side of the output of the rectifying circuit, which is the voltage supply source, and the positive input terminal on the DC side of the inverter circuit. The positive side main diode provided in the direction of flowing current from the positive side of the output of the inverter circuit to the positive input terminal on the DC side of the inverter circuit, and the negative side of the output of the rectifying circuit and the negative side of the DC side of the inverter circuit. A negative-side main diode provided at a position where the input terminal is connected so that a current flows from the negative input terminal on the DC side of the inverter circuit to the negative side of the output of the rectifier circuit, and the positive-side main diode. The positive side capacitor is located on the positive side at the position where it connects between the positive input terminal on the DC side of the inverter circuit and between the main diode on the negative side and the negative input terminal on the DC side of the inverter circuit. It is located between the main diode and the DC-side positive input terminal of the inverter circuit, and the negative-negative capacitor is located between the negative-negative main diode and the DC-side negative input terminal of the inverter circuit. The positive and negative side capacitors connected in series in the arrangement are connected between the positive side and the positive side main diode of the output of the rectifying circuit, and between the positive side side capacitor and the negative side side capacitor. A positive-current switching element that forms a circuit that connects both ends of the rectifying circuit and both ends of the negative-current side capacitor by being turned on by itself, and the negative side of the output of the rectifying circuit and the negative-current side. It is provided at a position connecting between the side main diode and the positive current side capacitor and the negative current side capacitor, and when it is turned on, both ends of the rectifying circuit and both ends of the positive current side capacitor are connected. By turning off both the booster circuit including the negative side switching element forming the circuit to be connected, the positive side switching element and the negative side switching element, the 1x DC voltage is supplied to the inverter circuit. The booster circuit is controlled so as to switch on / off while increasing the time for turning on the first switching element, which is one of the positive current side switching element and the negative current side switching element. Repeatedly, the first switching element of the positive current side switching element and the negative current side switching element The second switching element, which is the non-child switching element, is kept off, and when the duty ratio to the entire time of turning on the first switching element reaches a predetermined value, the first switching element Time for repeatedly turning on / off at a duty ratio of the predetermined value, providing a period for turning on the second switching element within the period for turning off the first switching element, and turning on the second switching element. By repeating on / off switching of the second switching element in response to repeated on / off switching of the first switching element while increasing the voltage, the DC voltage is increased , thereby boosting the voltage. The circuit includes a booster circuit control unit that controls the booster circuit so that the voltage supplied to the inverter circuit is gradually increased from the single voltage DC voltage to the double voltage DC voltage over a predetermined time .

The booster circuit control unit repeatedly turns on / off the third switching element, which is one of the positive-current side switching element and the negative-voltage side switching element, at the predetermined duty ratio, and the positive-voltage side. For the fourth switching element, which is the switching element other than the third switching element among the switching element and the negative voltage side switching element, the time for turning on the fourth switching element within the period during which the third switching element is turned off. The time for turning on the fourth switching element reaches 0 by repeating the on / off switching of the fourth switching element in response to the repeated on / off switching of the third switching element. Then, the DC voltage is reduced by maintaining the off state of the fourth switching element and repeating on / off switching while reducing the time for turning on the third switching element, thereby reducing the DC voltage. The booster circuit may be controlled so that the voltage supplied by the booster circuit to the inverter circuit is gradually reduced from the double voltage DC voltage to the single voltage DC voltage over a predetermined time .

According to the second aspect of the present invention, in the booster circuit control method, the booster voltage corresponds to twice the booster DC voltage from the booster DC voltage with respect to the inverter circuit that supplies power to the motor. A booster circuit that supplies a DC voltage within the range up to the DC voltage, at a position that connects the positive side of the output of the rectifying circuit, which is the voltage supply source, to the positive input terminal on the DC side of the inverter circuit. The positive side main diode provided in the direction of flowing current from the positive side of the output of the rectifying circuit to the positive input terminal on the DC side of the inverter circuit, and the negative side of the output of the rectifying circuit and the DC side of the inverter circuit. A negative main diode provided at a position where the negative input terminal is connected so that a current flows from the negative input terminal on the DC side of the inverter circuit to the negative side of the output of the rectifying circuit, and the positive main on the positive side. The positive side capacitor is located at a position connecting the diode and the positive input terminal on the DC side of the inverter circuit and between the main diode on the negative side and the negative input terminal on the DC side of the inverter circuit. It is located between the positive main diode and the positive input terminal on the DC side of the inverter circuit, and the negative capacitor is located between the main diode on the negative side and the negative input terminal on the DC side of the inverter circuit. Between the positive and negative side capacitors connected in series in a positioned arrangement, between the positive and positive side main diodes of the output of the rectifier circuit, and between the positive and negative side capacitors. A positive current side switching element that forms a circuit that connects both ends of the rectifying circuit and both ends of the negative current side capacitor by being turned on by itself, and a negative side of the output of the rectifying circuit. It is provided at a position connecting between the main diode on the negative side and between the capacitor on the positive side and the capacitor on the negative side, and when it is turned on, both ends of the rectifying circuit and both ends of the positive current side capacitor. The time for which the booster circuit including the negative-current side switching element forming the circuit for connecting the positive-current side and the negative-current side switching element turns on the first switching element, which is one of the positive-current side switching element and the negative-current side switching element. Switching on / off is repeated while increasing, and the second switching element, which is the switching element other than the first switching element among the positive current side switching element and the negative current side switching element, is maintained in the off state, and the first The duty ratio to the entire time of turning on one switching element is the place. When the constant value is reached, the first switching element is repeatedly turned on / off at the duty ratio of the predetermined value, and a period for turning on the second switching element is provided within the period for turning off the first switching element. By repeating the on / off switching of the second switching element in response to the repeated on / off switching of the first switching element while increasing the time for turning on the second switching element. The booster circuit is increased so that the voltage supplied by the booster circuit to the inverter circuit is gradually increased from the single voltage DC voltage to the double pressure DC voltage over a predetermined time by increasing the DC voltage. Including controlling.

According to a third aspect of the present invention, the program ranges from a 1x DC voltage to a 2x DC voltage equivalent to twice the 1x DC voltage for the inverter circuit that supplies power to the motor. A booster circuit that supplies DC voltage within the range of A positive main diode provided in a direction for flowing current from the positive side of the output to the positive input terminal on the DC side of the inverter circuit, and negative inputs on the negative side of the output of the rectifying circuit and the DC side of the inverter circuit. The negative side main diode provided at the position where the terminal is connected so that a current flows from the negative input terminal on the DC side of the inverter circuit to the negative side of the output of the rectifying circuit, the positive side main diode, and the above. The positive side capacitor is located between the positive input terminal on the DC side of the inverter circuit and between the main diode on the negative side and the negative input terminal on the DC side of the inverter circuit. Arranged so that the negative side capacitor is located between the diode and the positive input terminal on the DC side of the inverter circuit, and the negative side capacitor is located between the main diode on the negative side side and the negative input terminal on the DC side of the inverter circuit. The positive and negative side capacitors connected in series with the above, the positive side and the positive side main diode of the output of the rectifying circuit, and the positive side capacitor and the negative side capacitor are connected. A positive-current switching element that is provided at a position and forms a circuit that connects both ends of the rectifying circuit and both ends of the negative-current side capacitor by turning on itself, and the negative side and the negative-current side of the output of the rectifying circuit. It is provided at a position connecting between the main diode and between the positive current side capacitor and the negative current side capacitor, and when it is turned on, both ends of the rectifying circuit and both ends of the positive current side capacitor are connected. By turning off both the positive side switching element and the negative side switching element in the computer that controls the booster circuit including the negative side switching element forming the circuit, the booster DC voltage is applied to the inverter. The booster circuit is controlled so as to supply the circuit, and the first switching element, which is one of the positive-current side switching element and the negative-current side switching element, is turned on / off while increasing the time for turning on the first switching element . Switching is repeated, and among the positive current side switching element and the negative current side switching element, the said The second switching element, which is the switching element that is not the first switching element, is maintained in the off state, and when the duty ratio with respect to the entire time of turning on the first switching element reaches a predetermined value, the first The switching element is repeatedly turned on / off at a duty ratio of the predetermined value, a period for turning on the second switching element is provided within the period for turning off the first switching element, and the second switching element is turned on. The DC voltage is increased by repeating the on / off switching of the second switching element in response to the repeated on / off switching of the first switching element while increasing the time to be set. The booster circuit is controlled so that the voltage supplied by the booster circuit to the inverter circuit is gradually increased from the single voltage DC voltage to the double voltage DC voltage over a predetermined time . It is a program to control.

According to the above-mentioned inverter device, booster circuit control method and program, countermeasures against motor step-out can be taken by a relatively simple method.

It is a figure which shows the circuit structure of the inverter device which concerns on this embodiment. It is a schematic block diagram which shows the functional structure of the step-up circuit control part which concerns on the same embodiment. It is a figure which shows the example of the on / off of a positive electrode side switching element and a negative electrode side switching element when the booster circuit which concerns on the same embodiment supplies a 1x voltage DC voltage to an inverter circuit. It is a figure which shows the example of the on / off of a positive electrode side switching element and a negative electrode side switching element in the 1st stage in which the booster circuit which concerns on the same embodiment supplies an intermediate voltage to an inverter circuit, and the intermediate voltage gradually increases. It is a figure which shows the example of the on / off of a positive electrode side switching element and a negative electrode side switching element in the 2nd stage in which the booster circuit which concerns on the same embodiment supplies an intermediate voltage to an inverter circuit, and the intermediate voltage gradually increases. It is a figure which shows the example of the on / off of a positive electrode side switching element and a negative electrode side switching element when the booster circuit which concerns on the same embodiment supplies a double pressure DC voltage to an inverter circuit. In the same embodiment, it is a figure which shows the example which the DC voltage gradually changes from the 1x pressure DC voltage to the double pressure DC voltage. In the same embodiment, it is a figure which shows the example which the DC voltage gradually changes from a double-voltage DC voltage to a single-voltage DC voltage. In the same embodiment, when the positive electrode side switching element repeats on / off switching at a duty ratio of 50% with respect to the entire turn-on time, and the negative electrode side switching element continues to be in the off state, these switching elements It is a figure which shows the example of on / off. In the same embodiment, when the DC voltage increases, the positive electrode side switching element repeatedly switches on / off at a duty ratio of 50% with respect to the entire turn-on time, and the negative electrode side switching element continues to be off for a certain period of time. It is a figure which shows the example. In the same embodiment, when the DC voltage decreases, the positive electrode side switching element repeatedly switches on / off at a duty ratio of 50% with respect to the entire turn-on time, and the negative electrode side switching element continues to be off for a certain period of time. It is a figure which shows the example.

Hereinafter, embodiments of the present invention will be described, but the following embodiments do not limit the invention in the scope of claims. Also, not all combinations of features described in the embodiments are essential to the means of solving the invention.
(Circuit configuration of inverter device)
FIG. 1 is a diagram showing a circuit configuration of an inverter device according to the present embodiment.
The inverter device 1 is mounted on the outdoor unit of the air conditioner (air conditioner) 90. The inverter device 1 outputs a load driving AC voltage (three-phase AC voltage) according to a separately input rotation speed command to the three-phase AC motor (motor 4) for driving the compressor of the outdoor unit. do. The inverter device 1 rotationally drives the load three-phase AC motor (motor 4) at a desired rotation speed based on the load driving AC voltage.
The inverter device 1 converts the three-phase AC voltage supplied from the three-phase AC power supply 3, which is a commercial power source, into the load driving AC voltage and outputs the voltage. Here, the three-phase AC power supply 3 is, for example, an AC voltage having an AC of 200 V (effective value of 200 V) and a frequency of 50 Hz (or 60 Hz), and is composed of an R phase, an S phase, and a T phase whose phases differ by 120 ° from each other. Outputs the phase AC voltage. Hereinafter, the AC voltage of each phase output by the three-phase AC power supply 3 is also described as “R-phase AC voltage”, “S-phase AC voltage”, and “T-phase AC voltage”, respectively.

As shown in FIG. 1, the inverter device 1 includes a three-phase voltage doubler rectifier circuit 1A, an inverter circuit 20, an inverter circuit control unit 21, and a rotation speed detection unit 13.

The three-phase voltage doubler rectifier circuit 1A rectifies the three-phase AC voltage supplied from the three-phase AC power supply 3 and outputs "DC voltage Vdc". The DC voltage Vdc, which is the output voltage of the three-phase voltage doubler rectifier circuit 1A, is output between the positive electrode side output terminal Qa and the negative electrode side output terminal Qb shown in FIG.
As will be described later, the three-phase voltage doubler rectifier circuit 1A according to the present embodiment has a function as a voltage doubler rectifier circuit that outputs a double voltage of the maximum value of the input three-phase AC voltage.

The inverter circuit 20 converts the DC voltage Vdc output from the three-phase voltage doubler rectifier circuit 1A into a load driving AC voltage for rotationally driving the motor 4. The inverter circuit 20 has three pairs of two switching elements connected in series between the positive electrode side output terminal Qa and the negative electrode side output terminal Qb. Here, the switching element is, for example, a power transistor such as an insulated gate bipolar transistor (IGBT). Each pair of the switching elements connected in series corresponds to each of the three phases for rotationally driving the three-phase AC motor (motor 4).
The inverter circuit 20 further includes a motor current detection unit 22.
The motor current detection unit 22 detects the current (motor current) returning to the three-phase voltage doubler rectifier circuit 1A. The motor current detection unit 22 outputs the detection result of the detected motor current as a detection signal to the inverter circuit control unit 21.

The inverter circuit control unit 21 is a control IC (so-called microcomputer or the like) that controls on / off of each switching element constituting the inverter circuit 20.
A rotation speed command is input to the inverter circuit control unit 21 from the host device. The inverter circuit control unit 21 receives a motor current detection signal from the motor current detection unit 22.
The inverter circuit control unit 21 drives the inverter circuit 20 so that the rotation speed of the motor 4 becomes the rotation speed indicated by the rotation speed command while monitoring the motor current. Here, the inverter circuit control unit 21 controls the inverter circuit 20 based on the generally well-known PWM (Pulse Width Modulation) control.

(Construction of three-phase voltage doubler rectifier circuit)
The circuit configuration of the three-phase voltage doubler rectifier circuit 1A will be described in detail.
As shown in FIG. 1, the three-phase voltage doubler rectifier circuit 1A includes a rectifier circuit 10, a booster circuit 11, a booster circuit control unit 12, and a reactor L.

The rectifier circuit 10 rectifies the three-phase AC voltage supplied from the three-phase AC power supply 3 and outputs the rectified voltage Vac.
The booster circuit 11 can output a voltage that is twice the maximum value of the three-phase AC voltage input from the three-phase AC power supply 3 as a DC voltage Vdc under the control of the booster circuit control unit 12.
The booster circuit control unit 12 is a control IC that controls the booster circuit 11. The specific functional configuration of the booster circuit control unit 12 will be described later.
The rectifier circuit 10 and the booster circuit 11 are connected to each other on the positive electrode side by a positive electrode output line α via the reactor L. The rectifier circuit 10 and the booster circuit 11 are connected to each other on the negative electrode side by a negative electrode output line β.

The reactor L smoothes the current flowing through the positive electrode output line α.
In the following description, the positive electrode output line α is a line in which the first positive electrode output line α1 and the second positive electrode output line α2 are connected in series via the reactor L.
Therefore, the rectifier circuit 10 outputs the rectified voltage Vac between the first positive electrode output line α1 and the negative electrode output line β.

(Rectifier circuit configuration)
The rectifier circuit 10 will be described in detail.
The rectifying circuit 10 inputs the three-phase AC voltage (R-phase AC voltage, S-phase AC voltage, and T-phase AC voltage) supplied from the three-phase AC power supply 3 to three input terminals (R-phase input) corresponding to each phase. Input from each of the terminal QR, S-phase input terminal QS, and T-phase input terminal QT) to rectify.

Each of the R-phase AC voltage, the S-phase AC voltage, and the T-phase AC voltage vibrates with a period Tc while being out of phase with each other by 120 °.
The rectifier circuit 10 includes six rectifier diodes (positive side R-phase rectifier diode 10Ra, negative-side R-phase rectifier diode 10Rb, positive-side S-phase rectifier diode 10Sa, negative-side S-phase rectifier diode 10Sb, positive-side T-phase rectifier diode 10Ta, and It is composed of a negative side T-phase rectifying diode 10Tb).

The positive-side R-phase rectifier diode 10Ra and the negative-side R-phase rectifier diode 10Rb of the rectifier circuit 10 rectify the R-phase AC voltage input from the three-phase AC power supply 3 through the R-phase input terminal QR. Specifically, the positive electrode side R phase rectifier diode 10Ra is forwardly connected from the R phase input terminal QR to the first positive electrode output line α1. Further, the negative electrode side R phase rectifying diode 10Rb is forwardly connected from the negative electrode output line β to the R phase input terminal QR.

The positive side S-phase rectifier diode 10Sa and the negative side S-phase rectifier diode 10Sb of the rectifier circuit 10 rectify the S-phase AC voltage input from the three-phase AC power supply 3 through the S-phase input terminal QS. Specifically, the positive electrode side S-phase rectifying diode 10Sa is forwardly connected from the S-phase input terminal QS to the first positive electrode output line α1. Further, the negative electrode side S-phase rectifying diode 10Sb is forwardly connected from the negative electrode output line β to the S-phase input terminal QS.

The positive side T-phase rectifier diode 10Ta and the negative side T-phase rectifier diode 10Tb of the rectifier circuit 10 rectify the T-phase AC voltage input from the three-phase AC power supply 3 through the T-phase input terminal QT. Specifically, the positive electrode side T-phase rectifying diode 10Ta is forwardly connected from the T-phase input terminal QT to the first positive electrode output line α1. Further, the negative electrode side T-phase rectifying diode 10Tb is forwardly connected from the negative electrode output line β to the T-phase input terminal QT.

(Boost circuit)
The booster circuit 11 will be described in detail.
The booster circuit 11 can output a voltage twice the maximum value of the three-phase AC voltage input from the three-phase AC power supply 3 as the DC voltage Vdc which is the output voltage of the three-phase voltage doubler rectifier circuit 1A. ..
Here, in the following description, the DC voltage Vdc corresponding to the amplitude of the three-phase AC voltage is described as "single voltage DC voltage Vdc1", and the DC voltage Vdc equivalent to twice the amplitude of the three-phase AC voltage is described as "1x voltage DC voltage Vdc1". It is distinguished by describing it as "double voltage DC voltage Vdc2" (Vdc1 = 1/2 · Vdc2). For example, when the three-phase AC power supply 3 outputs an AC voltage of AC200V, the single-voltage DC voltage Vdc1 becomes 200√2V, and the double-voltage DC voltage Vdc2 becomes 400√2V. Further, the voltage between the single voltage DC voltage Vdc1 and the double voltage DC voltage Vdc2 is described as "intermediate voltage Vdc3". Vdc1 <Vdc3 <Vdc2.
The 1x DC voltage Vdc1 corresponds to an example of a reference voltage which is a voltage before being boosted.

The booster circuit 11 comprises a positive electrode side main diode Da, a negative electrode side main diode Db, a positive electrode side switching element 11a, a negative electrode side switching element 11b, and two capacitors (positive electrode side capacitor Ca and negative electrode side capacitor Cb). Be prepared.

The two capacitors (positive electrode side capacitor Ca and negative electrode side capacitor Cb) are connected in series between the outputs on the output side of the booster circuit 11.
Specifically, the positive electrode side capacitor Ca is connected between the cathode of the positive electrode side main diode Da and the connection point N. The negative electrode side capacitor Cb is connected between the anode of the negative electrode side main diode Db and the connection point N.
The positive electrode side capacitor Ca and the negative electrode side capacitor Cb have the same capacitance value. Therefore, the connection point N is an intermediate potential point of the potential difference between the positive electrode output line α and the negative electrode output line β.

The positive electrode side main diode Da is connected in the forward direction from the positive electrode output line α of the rectifier circuit 10 to the positive electrode side capacitor Ca. Specifically, the anode of the positive electrode side main diode Da is connected to the second positive electrode output line α2, and the cathode of the positive electrode side main diode Da is connected to the positive electrode side capacitor Ca.
The negative electrode side main diode Db is connected in the forward direction from the negative electrode side capacitor Cb to the negative electrode output line β of the rectifier circuit 10. Specifically, the anode of the negative electrode side main diode Db is connected to the negative electrode side capacitor Cb, and the cathode of the negative electrode side main diode Db is connected to the negative electrode output line β.

The positive electrode side switching element 11a and the negative electrode side switching element 11b are power transistors, respectively.
The positive electrode side switching element 11a is connected between the positive electrode output line α (second positive electrode output line α2) and the connection point N. The negative electrode side switching element 11b is connected between the negative electrode output line β and the connection point N.
The positive electrode side switching element 11a and the negative electrode side switching element 11b are on / off controlled by a switching control signal output from the booster circuit control unit 12 described later.

In the case of this embodiment, the positive electrode side switching element 11a and the negative electrode side switching element 11b are IGBTs, respectively.
In this case, the collector of the positive electrode side switching element 11a is connected to the second positive electrode output line α2, and the emitter of the positive electrode side switching element 11a is connected to the connection point N. Further, the emitter of the negative electrode side switching element 11b is connected to the negative electrode output line β, and the collector of the negative electrode side switching element 11b is connected to the connection point N.
By applying a switching control signal from the booster circuit control unit 12 described later to the gate of the positive electrode side switching element 11a, the positive electrode side switching element 11a is controlled on / off.
Similarly, the negative electrode side switching element 11b is on / off controlled by applying a switching control signal from the booster circuit control unit 12 to the gate of the negative electrode side switching element 11b.

(Boost circuit control unit)
The booster circuit control unit 12 will be described in detail.
FIG. 2 is a schematic block diagram showing a functional configuration of the booster circuit control unit 12.
As shown in FIG. 2, the booster circuit control unit 12 includes a switching operation determination unit 12d and a switching element control unit 12g.

The switching operation determination unit 12d determines the operation to be performed by the positive electrode side switching element 11a and the negative electrode side switching element 11b. In particular, the switching operation determining unit 12d determines the time width for turning on each of the positive electrode side switching element 11a and the negative electrode side switching element 11b.
The switching element control unit 12g controls on / off of the positive electrode side switching element 11a and the negative electrode side switching element 11b according to the operation determined by the switching operation determination unit 12d.

Next, the operation of the inverter device 1 will be described with reference to FIGS. 3 to 11.
Hereinafter, the state in which the DC voltage Vdc is the single-voltage DC voltage Vdc1 (the booster circuit 11 supplies the single-voltage DC voltage Vdc1 to the inverter circuit 20) will be described as the single-voltage mode. The state in which the DC voltage Vdc is the intermediate voltage Vdc3 (the booster circuit 11 supplies the intermediate voltage Vdc3 to the inverter circuit 20) is referred to as an intermediate voltage mode. The state in which the DC voltage Vdc is the double voltage DC voltage Vdc2 (the booster circuit 11 supplies the double voltage DC voltage Vdc2 to the inverter circuit 20) is described as the double pressure mode.

FIG. 3 is a diagram showing an example of turning on / off the positive electrode side switching element 11a and the negative electrode side switching element 11b when the booster circuit 11 supplies a single-voltage DC voltage to the inverter circuit 20. The horizontal axis in FIG. 3 indicates the time.
When the booster circuit 11 supplies the booster DC voltage to the inverter circuit 20, the switching element control unit 12g leaves both the positive electrode side switching element 11a and the negative electrode side switching element 11b in the off state.

When the rotation speed of the motor 4 detected by the rotation speed detection unit 13 becomes larger than a predetermined threshold value in the single pressure mode, the booster circuit control unit 12 controls the booster circuit 11 to supply an intermediate voltage to the inverter circuit 20. .. At that time, the booster circuit control unit 12 controls the booster circuit 11 so that the DC voltage Vdc supplied from the booster circuit 11 to the inverter circuit 20 gradually increases.

FIG. 4 shows an example of turning on / off the positive electrode side switching element 11a and the negative electrode side switching element 11b in the first stage in which the booster circuit 11 supplies an intermediate voltage to the inverter circuit 20 and the intermediate voltage Vdc3 gradually increases. It is a figure. The horizontal axis in FIG. 4 indicates the time.
The booster circuit control unit 12 provides a time for the positive electrode side switching element 11a to turn on, and repeats on / off switching of the positive electrode side switching element 11a to change the DC voltage Vdc from the single voltage DC voltage Vdc1 to the intermediate voltage Vdc3. Switch to. Further, the booster circuit control unit 12 gradually increases the DC voltage Vdc (intermediate voltage Vdc3) by gradually lengthening the time during which the positive electrode side switching element 11a is turned on. The booster circuit control unit 12 gradually increases the time during which the positive electrode side switching element 11a is turned on according to the elapsed time from the change from the single voltage mode to the intermediate voltage mode, for example.

When the positive electrode side switching element 11a is turned on, a circuit connecting both ends of the rectifying circuit 10 and both ends of the negative electrode side capacitor Cb is formed, and a voltage corresponding to the 1x DC voltage Vdc1 is applied to the negative electrode side capacitor Cb. Power is stored. Due to this storage, the voltage of the negative electrode side capacitor Cb becomes higher than in the single voltage mode, and the DC voltage Vdc becomes an intermediate voltage larger than the single voltage DC voltage. As the time for the positive electrode side switching element 11a to be turned on becomes longer, the amount of electricity stored in the negative electrode side capacitor Cb increases, and the voltage of the negative electrode side capacitor Cb increases. As a result, the DC voltage Vdc, which is the intermediate voltage Vdc3, becomes large.

When the duty ratio to the entire time when the positive electrode side switching element 11a is turned on reaches 50%, the booster circuit control unit 12 switches the negative electrode side within the range of the time when the positive electrode side switching element 11a is turned off. A time is provided for the element 11b to turn on, and on / off switching of the negative electrode side switching element 11b is repeated. Further, the booster circuit control unit 12 gradually increases the DC voltage Vdc (intermediate voltage Vdc3) by gradually lengthening the time during which the negative electrode side switching element 11b is turned on.

FIG. 5 shows an example of turning on / off the positive electrode side switching element 11a and the negative electrode side switching element 11b in the second stage in which the booster circuit 11 supplies an intermediate voltage to the inverter circuit 20 and the intermediate voltage Vdc3 gradually increases. It is a figure. The horizontal axis in FIG. 5 indicates the time.
The booster circuit control unit 12 maintains a duty ratio of 50% with respect to the entire time during which the positive electrode side switching element 11a is turned on, and the negative electrode side switching element is within the range of the time during which the positive electrode side switching element 11a is turned off. A time is provided for the 11b to turn on, and the on / off switching of the negative electrode side switching element 11b is repeated. Further, the booster circuit control unit 12 gradually increases the DC voltage Vdc (intermediate voltage Vdc3) by gradually lengthening the time during which the negative electrode side switching element 11b is turned on.

When the negative electrode side switching element 11b is turned on, a circuit connecting both ends of the rectifying circuit 10 and both ends of the positive electrode side capacitor Ca is formed, and a voltage corresponding to the 1x DC voltage Vdc1 is applied to the positive electrode side capacitor Ca. Power is stored. Due to this storage, the voltage of the positive electrode side capacitor Ca becomes higher than in the single voltage mode, and the DC voltage Vdc becomes a larger intermediate voltage than in the case where only the positive electrode side switching element 11a is repeatedly turned on / off (see FIG. 4). .. As the negative electrode side switching element 11b is turned on for a longer time, the amount of electricity stored in the positive electrode side capacitor Ca increases, and the voltage of the positive electrode side capacitor Ca increases. As a result, the DC voltage Vdc, which is the intermediate voltage Vdc3, becomes large. The booster circuit control unit 12 gradually increases the time during which the negative electrode side switching element 11b is turned on according to the elapsed time after the duty ratio reaches 50% of the total time during which the positive electrode side switching element 11a is turned on. I will make it longer.

FIG. 6 is a diagram showing an example of turning on / off the positive electrode side switching element 11a and the negative electrode side switching element 11b when the booster circuit 11 supplies a double voltage DC voltage to the inverter circuit 20. The horizontal axis in FIG. 6 indicates the time.
When the time for the negative electrode side switching element 11b to be turned on becomes long and the duty ratio for the entire time for the negative electrode side switching element 11b to be turned on reaches 50%, the on / off illustrated in FIG. 6 is performed. In the example of FIG. 6, the booster circuit control unit 12 repeats on / off switching so that one of the positive electrode side switching element 11a and the negative electrode side switching element 11b is turned on and the other is turned off.
The voltage of each of the positive electrode side capacitor Ca and the negative electrode side capacitor Cb becomes a voltage corresponding to the single voltage DC voltage Vdc1 by storing electricity, so that the DC voltage Vdc becomes the double voltage DC voltage Vdc2.

The inverter circuit control unit 21 has the same control as when the DC voltage Vdc is the single voltage DC voltage Vdc1 (see FIG. 3) in a state where only the positive electrode side switching element 11a repeats on / off (see FIG. 4). It controls the inverter circuit 20. Further, in the inverter circuit control unit 21, in a state where both the positive side switching element 11a and the negative side switching element 11b are repeatedly turned on / off (see FIGS. 5 and 6), the DC voltage Vdc is double-voltage DC voltage Vdc2. The inverter circuit 20 is controlled by the control at a certain time (see FIG. 6).
In particular, the inverter circuit control unit 21 switches the calculation reference of the pulse width in the PWM control in two stages of the case of the double voltage DC voltage Vdc1 and the case of the double voltage DC voltage Vdc2. When the double-voltage DC voltage Vdc2 is used, the standard for calculating the pulse width to half that of the single-voltage DC voltage Vdc1 is used.

In this way, the inverter circuit control unit 21 switches the pulse width in the PWM control, and the booster circuit control unit 12 controls the booster circuit 11 to adjust the DC voltage Vdc so that the pulse width becomes relatively wide. In this respect, the efficiency of power supply to the motor 4 can be made relatively high.
Further, the inverter circuit control unit 21 can control the inverter circuit 20 in response to a change in the DC voltage Vdc by a relatively simple process of switching the pulse width in PWM control in two stages.

FIG. 7 is a diagram showing an example in which the DC voltage Vdc gradually changes from a single-voltage DC voltage to a double-voltage DC voltage. The horizontal axis of the graph of FIG. 7 shows the time, and the vertical axis shows the DC voltage Vdc.
In the example of FIG. 7, the booster circuit control unit 12 controls the booster circuit 11 to gradually change the DC voltage Vdc from the single voltage DC voltage Vdc1 to the double voltage DC voltage Vdc2.

As described above, when the rotation speed of the motor 4 detected by the rotation speed detection unit 13 becomes larger than a predetermined threshold value in the single voltage mode, the booster circuit control unit 12 sets the time for the positive electrode side switching element 11a to turn on. By repeatedly turning on / off the positive electrode side switching element 11a, the DC voltage Vdc is switched from the single voltage DC voltage Vdc1 to the intermediate voltage Vdc3. Further, the booster circuit control unit 12 gradually increases the DC voltage Vdc (intermediate voltage Vdc3) by gradually lengthening the time during which the positive electrode side switching element 11a is turned on.

When the duty ratio to the entire time when the positive electrode side switching element 11a is turned on reaches 50%, the booster circuit control unit 12 switches the negative electrode side within the range of the time when the positive electrode side switching element 11a is turned off. A time is provided for the element 11b to turn on, and on / off switching of the negative electrode side switching element 11b is repeated. Further, the booster circuit control unit 12 gradually increases the DC voltage Vdc (intermediate voltage Vdc3) by gradually lengthening the time during which the negative electrode side switching element 11b is turned on.

When the duty ratio to the entire time during which the negative electrode side switching element 11b is turned on reaches 50%, the booster circuit control unit 12 turns on either the positive electrode side switching element 11a or the negative electrode side switching element 11b. Repeat on / off switching so that the other is off. As a result, the DC voltage Vdc becomes the double voltage DC voltage Vdc2.

By gradually changing the DC voltage Vdc from the single voltage DC voltage Vdc1 to the double voltage DC voltage Vdc2, the motor is compared with the case where the single voltage DC voltage Vdc1 is directly switched to the double voltage DC voltage Vdc2. Sudden changes in the voltage supplied to 4 can be suppressed. This makes it possible to reduce the possibility that the motor 4 will step out.

FIG. 8 is a diagram showing an example in which the DC voltage Vdc gradually changes from a double voltage DC voltage to a single voltage DC voltage. The horizontal axis of the graph of FIG. 8 indicates the time, and the vertical axis indicates the DC voltage Vdc.
In the example of FIG. 8, the booster circuit control unit 12 controls the booster circuit 11 to gradually change the DC voltage Vdc from the double voltage DC voltage Vdc2 to the double voltage DC voltage Vdc1.

In the double voltage mode, when the rotation speed of the motor 4 detected by the rotation speed detection unit 13 becomes smaller than a predetermined threshold value, the booster circuit control unit 12 gradually shortens the time during which the negative electrode side switching element 11b is turned on. By going on, the DC voltage Vdc is gradually reduced from the double voltage DC voltage Vdc2.
When the negative electrode side switching element 11b is turned on for 0, that is, the negative electrode side switching element 11b is kept off, the booster circuit control unit 12 gradually sets the time for the positive electrode side switching element 11a to be turned on. By shortening the voltage to Vdc, the DC voltage Vdc is gradually reduced.
When the time when the positive electrode side switching element 11a is turned on is 0, that is, when the positive electrode side switching element 11a is kept off, the DC voltage Vdc becomes the 1x voltage DC voltage Vdc1.

By gradually changing the DC voltage Vdc from the double voltage DC voltage Vdc2 to the single voltage DC voltage Vdc1, the motor is compared with the case where the double voltage DC voltage Vdc2 is directly switched to the single voltage DC voltage Vdc1. Sudden changes in the voltage supplied to 4 can be suppressed. This makes it possible to reduce the possibility that the motor 4 will step out.

The booster circuit control unit 12 repeats on / off switching of the positive electrode side switching element 11a at a duty ratio of 50% with respect to the entire turn-on time, and keeps the negative electrode side switching element 11b off for a certain period of time. You may do so.
FIG. 9 shows a case where the positive electrode side switching element 11a repeatedly switches on / off at a duty ratio of 50% with respect to the entire turn-on time, and the negative electrode side switching element 11b continues to be in the off state. It is a figure which shows the example of on / off of. The horizontal axis in FIG. 9 indicates the time.

In FIG. 10, when the DC voltage Vdc is increased, the positive electrode side switching element 11a repeatedly switches on / off at a duty ratio of 50% with respect to the entire time of turning on, and the negative electrode side switching element 11b is in a constant off state. It is a figure which shows the example of continuation of time.
The horizontal axis of the graph of FIG. 10 indicates the time, and the vertical axis indicates the DC voltage Vdc.
In the example of FIG. 10, from time T1 to T2, the booster circuit control unit 12 repeats on / off switching of the positive electrode side switching element 11a at a duty ratio of 50% with respect to the entire time of turning on, and the negative electrode. The side switching element 11b is kept off for a certain period of time. As a result, the value of the DC voltage Vdc is constant from the time T1 to T2. Other than that, it is the same as in FIG. 7.

In this way, by providing a time for the DC voltage Vdc to continue at a constant value at the intermediate voltage Vdc3, the change in the voltage supplied to the motor 4 can be further moderated. This makes it possible to reduce the possibility that the motor 4 will step out.
While the DC voltage Vdc continues to be a constant value at the intermediate voltage Vdc3, the inverter circuit control unit 21 controls the inverter circuit 20 in the same manner as in either the single pressure mode or the double pressure mode. You may do it. Alternatively, while the DC voltage Vdc continues to be a constant value at the intermediate voltage Vdc3, the inverter circuit control unit 21 controls the inverter circuit 20 by a control different from that in the case of the single voltage mode and the case of the double voltage mode. You may do so.

In FIG. 11, when the DC voltage Vdc decreases, the positive electrode side switching element 11a repeatedly switches on / off at a duty ratio of 50% with respect to the entire turn-on time, and the negative electrode side switching element 11b remains off. It is a figure which shows the example of continuation of time.
The horizontal axis of the graph of FIG. 11 indicates the time, and the vertical axis indicates the DC voltage Vdc.
In the example of FIG. 11, from time T3 to T4, the booster circuit control unit 12 repeats on / off switching of the positive electrode side switching element 11a at a duty ratio of 50% with respect to the entire time of turning on, and the negative electrode. The side switching element 11b is kept off for a certain period of time. As a result, the value of the DC voltage Vdc is constant from the time T1 to T2. Other than that, it is the same as the case of FIG.
In this way, by providing a time for the DC voltage Vdc to continue at a constant value at the intermediate voltage Vdc3, the change in the voltage supplied to the motor 4 can be further moderated. This makes it possible to reduce the possibility that the motor 4 will step out.

As described above, on / off switching is repeated while increasing the time for turning on one of the positive electrode side switching element 11a and the negative electrode side switching element 11b, and the time for turning on the switching element. When the duty ratio with respect to the entire time reaches a predetermined value, the DC voltage Vdc is increased by repeating on / off switching while increasing the time for turning on the other switching element.
As a result, in the inverter device 1, the DC voltage Vdc can be gradually increased, and the possibility of step-out of the motor 4 can be reduced.
Further, in the inverter device 1, it is not necessary to change the time for turning on the positive electrode side switching element 11a and the time for turning on the negative electrode side switching element 11b at the same time. Can be done at.

Further, on / off switching is repeated while reducing the time for turning on one of the positive electrode side switching element 11a and the negative electrode side switching element 11b, and the time for turning on the switching element reaches 0. Then, the DC voltage Vdc is reduced by repeating on / off switching while reducing the time for turning on the other switching element.
As a result, in the inverter device 1, the DC voltage Vdc can be gradually reduced, and the possibility of step-out of the motor 4 can be reduced.
Further, in the inverter device 1, it is not necessary to change the time for turning on the positive electrode side switching element 11a and the time for turning on the negative electrode side switching element 11b at the same time. Can be done at.

A program for realizing all or part of the functions of the booster circuit control unit 12 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read by the computer system and executed. May be processed for each part. The term "computer system" as used herein includes hardware such as an OS and peripheral devices.
Further, the "computer system" includes the homepage providing environment (or display environment) if the WWW system is used.
Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, or a CD-ROM, and a storage device such as a hard disk built in a computer system. Further, the above-mentioned program may be for realizing a part of the above-mentioned functions, and may be further realized for realizing the above-mentioned functions in combination with a program already recorded in the computer system.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment and includes design changes and the like within a range not deviating from the gist of the present invention.

1 Inverter device 1A Three-phase voltage doubler rectifier circuit 4 Motor 10 Rectifier circuit 11 Booster circuit 11a Positive side switching element 11b Negative side switching element Ca Positive side capacitor Cb Negative side capacitor 12 Booster circuit control unit 12d Switching operation determination unit 12g Switching element control Part 13 Rotation speed detection part 20 Inverter circuit 21 Inverter circuit control part

Claims (4)

It is a booster circuit that supplies DC voltage to the inverter circuit that supplies power to the motor within the range from the 1x DC voltage to the 2x DC voltage that corresponds to twice the 1x DC voltage. ,
A positive input on the DC side of the inverter circuit from the positive side of the output of the rectifier circuit at a position connecting the positive side of the output of the rectifier circuit, which is the voltage supply source, and the positive input terminal on the DC side of the inverter circuit. The main diode on the positive side, which is provided in the direction of passing current to the terminals,
A current is applied from the negative input terminal on the DC side of the inverter circuit to the negative side of the output of the rectifier circuit at the position where the negative side of the output of the rectifier circuit and the negative input terminal on the DC side of the inverter circuit are connected. The main diode on the negative side, which is provided in the direction of flow,
A positive electrode is located between the positive electrode side main diode and the positive input terminal on the DC side of the inverter circuit, and between the negative electrode side main diode and the negative input terminal on the DC side of the inverter circuit. The side capacitor is located between the positive side main diode and the DC side positive input terminal of the inverter circuit, and the negative side capacitor is the negative side main diode and the DC side negative input terminal of the inverter circuit. Positive current side capacitors and negative negative side capacitors connected in series in an arrangement located on the intervening side,
The rectifying circuit is provided at a position connecting between the positive side of the output of the rectifying circuit and the main diode on the positive electrode side, and between the capacitor on the positive electrode side and the capacitor on the negative electrode side. A positive electrode side switching element forming a circuit connecting both ends of the negative electrode side capacitor and both ends of the negative electrode side capacitor,
The rectifying circuit is provided at a position connecting between the negative side of the output of the rectifying circuit and the main diode on the negative electrode side, and between the capacitor on the positive electrode side and the capacitor on the negative electrode side. A negative electrode side switching element forming a circuit connecting both ends of the positive electrode side capacitor and both ends of the positive electrode side capacitor,
With a booster circuit and
By turning off both the positive side switching element and the negative side switching element, the booster circuit is controlled so that the single voltage DC voltage is supplied to the inverter circuit, and the positive side switching element and the negative side are used. The on / off switching is repeated while increasing the time for turning on the first switching element, which is one of the side switching elements, and the first switching among the positive side switching element and the negative side switching element. The second switching element, which is the switching element that is not the element, is maintained in the off state, and when the duty ratio to the entire time of turning on the first switching element reaches a predetermined value, the first switching element A time for repeatedly turning on / off at a duty ratio of the predetermined value, providing a period for turning on the second switching element within the period for turning off the first switching element, and turning on the second switching element. By repeating on / off switching of the second switching element in response to repeated on / off switching of the first switching element while increasing the voltage, the DC voltage is increased , thereby boosting the voltage. A booster circuit control unit that controls the booster circuit so that the voltage supplied to the inverter circuit by the circuit is gradually increased from the single voltage DC voltage to the double voltage DC voltage over a predetermined time .
Inverter device with. The booster circuit control unit
The third switching element, which is one of the positive side switching element and the negative side switching element, is repeatedly turned on / off at the predetermined duty ratio, and the positive side switching element and the negative side switching element are repeatedly switched. Regarding the fourth switching element, which is the switching element other than the third switching element, the first switching element is turned on while reducing the time for turning on the fourth switching element within the period in which the third switching element is turned off . When the on / off switching of the fourth switching element is repeated in response to the repeated on / off switching of the third switching element and the time for turning on the fourth switching element reaches 0, the fourth switching element The DC voltage is reduced by repeating on / off switching while maintaining the off state and reducing the time for turning on the third switching element , whereby the booster circuit becomes the inverter circuit. The booster circuit is controlled so that the supplied voltage is gradually reduced from the double-voltage DC voltage to the single-voltage DC voltage over a predetermined time.
The inverter device according to claim 1. It is a booster circuit that supplies DC voltage to the inverter circuit that supplies power to the motor within the range from the 1x DC voltage to the 2x DC voltage that corresponds to twice the 1x DC voltage. ,
A positive input on the DC side of the inverter circuit from the positive side of the output of the rectifier circuit at a position connecting the positive side of the output of the rectifier circuit, which is the voltage supply source, and the positive input terminal on the DC side of the inverter circuit. The main diode on the positive side, which is provided in the direction of passing current to the terminals,
A current is applied from the negative input terminal on the DC side of the inverter circuit to the negative side of the output of the rectifier circuit at the position where the negative side of the output of the rectifier circuit and the negative input terminal on the DC side of the inverter circuit are connected. The main diode on the negative side, which is provided in the direction of flow,
A positive electrode is located between the positive electrode side main diode and the positive input terminal on the DC side of the inverter circuit, and between the negative electrode side main diode and the negative input terminal on the DC side of the inverter circuit. The side capacitor is located between the positive side main diode and the DC side positive input terminal of the inverter circuit, and the negative side capacitor is the negative side main diode and the DC side negative input terminal of the inverter circuit. Positive current side capacitors and negative negative side capacitors connected in series in an arrangement located on the intervening side,
The rectifying circuit is provided at a position connecting between the positive side of the output of the rectifying circuit and the main diode on the positive electrode side, and between the capacitor on the positive electrode side and the capacitor on the negative electrode side. A positive electrode side switching element forming a circuit connecting both ends of the negative electrode side capacitor and both ends of the negative electrode side capacitor,
The rectifying circuit is provided at a position connecting between the negative side of the output of the rectifying circuit and the main diode on the negative electrode side, and between the capacitor on the positive electrode side and the capacitor on the negative electrode side. A negative electrode side switching element forming a circuit connecting both ends of the positive electrode side capacitor and both ends of the positive electrode side capacitor,
The booster circuit with
On / off switching is repeated while increasing the time for turning on the first switching element, which is one of the positive side switching element and the negative side switching element, and the positive side switching element and the negative side switching element are switched. When the second switching element, which is the switching element other than the first switching element, is kept off, and the duty ratio to the entire time for turning on the first switching element reaches a predetermined value. The first switching element is repeatedly turned on / off at a duty ratio of the predetermined value, and a period for turning on the second switching element is provided within the period for turning off the first switching element. While increasing the time for turning on the switching element, the DC voltage is increased by repeating the on / off switching of the second switching element in response to the repeated on / off switching of the first switching element. By doing so, the booster circuit is controlled so that the voltage supplied to the inverter circuit by the booster circuit is gradually increased from the single voltage DC voltage to the double voltage DC voltage over a predetermined time . Booster circuit control method including. It is a booster circuit that supplies DC voltage to the inverter circuit that supplies power to the motor within the range from the 1x DC voltage to the 2x DC voltage that corresponds to twice the 1x DC voltage. ,
A positive input on the DC side of the inverter circuit from the positive side of the output of the rectifier circuit at a position connecting the positive side of the output of the rectifier circuit, which is the voltage supply source, and the positive input terminal on the DC side of the inverter circuit. The main diode on the positive side, which is provided in the direction of passing current to the terminals,
A current is applied from the negative input terminal on the DC side of the inverter circuit to the negative side of the output of the rectifier circuit at the position where the negative side of the output of the rectifier circuit and the negative input terminal on the DC side of the inverter circuit are connected. The main diode on the negative side, which is provided in the direction of flow,
A positive electrode is located between the positive electrode side main diode and the positive input terminal on the DC side of the inverter circuit, and between the negative electrode side main diode and the negative input terminal on the DC side of the inverter circuit. The side capacitor is located between the positive side main diode and the DC side positive input terminal of the inverter circuit, and the negative side capacitor is the negative side main diode and the DC side negative input terminal of the inverter circuit. Positive current side capacitors and negative negative side capacitors connected in series in an arrangement located on the intervening side,
The rectifying circuit is provided at a position connecting between the positive side of the output of the rectifying circuit and the main diode on the positive electrode side, and between the capacitor on the positive electrode side and the capacitor on the negative electrode side. A positive electrode side switching element forming a circuit connecting both ends of the negative electrode side capacitor and both ends of the negative electrode side capacitor,
The rectifying circuit is provided at a position connecting between the negative side of the output of the rectifying circuit and the main diode on the negative electrode side, and between the capacitor on the positive electrode side and the capacitor on the negative electrode side. A negative electrode side switching element forming a circuit connecting both ends of the positive electrode side capacitor and both ends of the positive electrode side capacitor,
For computers that control booster circuits,
By turning off both the positive side switching element and the negative side switching element, the booster circuit is controlled so as to supply the booster DC voltage to the inverter circuit, and the positive side switching element and the negative side are used. The on / off switching is repeated while increasing the time for turning on the first switching element, which is one of the switching elements, and the first switching element among the positive side switching element and the negative side switching element. The second switching element, which is the non-switching element, is maintained in the off state, and when the duty ratio to the entire time of turning on the first switching element reaches a predetermined value, the first switching element is described. Switching on / off is repeated at a predetermined duty ratio, a period for turning on the second switching element is provided within the period for turning off the first switching element, and the time for turning on the second switching element is set. The DC voltage is increased by repeating the on / off switching of the second switching element in response to the repeated on / off switching of the first switching element while increasing the voltage, thereby increasing the booster circuit. To control the booster circuit so as to gradually increase the voltage supplied to the inverter circuit from the single-voltage DC voltage to the double-voltage DC voltage over a predetermined time . program.

Images