JP6346583B2 - Motor drive control device and fan motor system provided with the same - Google Patents

Description

  The present invention relates to a motor drive control device and a fan motor system including the same.

  Various devices that generate heat often have a cooling fan. Therefore, such an apparatus includes an electric motor for driving the fan and a motor drive control device for controlling the electric motor.

  In addition, with respect to equipment equipped with a fan motor system, an operator may take out some units for maintenance, for example, or open a case to disassemble the unit. In such a case, the worker usually starts work after the device is turned off. However, even if the power supply to the device is cut off, the fan motor is inertial and continues to rotate for a while. Therefore, the worker cannot start work while the fan is rotating.

  Therefore, conventionally, as in Patent Document 1, for example, a motor control device having a function of automatically braking the motor when the supply of electric power is stopped has been developed.

  In Patent Document 1, as described in paragraph 0009, when power supply from the power supply is stopped, the connection switch is operated when the power supply is stopped, and the switch group is configured by the power stored in the capacitor. A motor control device is disclosed in which some switches are operated and each coil is short-circuited by some switch operations to brake the motor.

  In the technique of Patent Document 1, as described in paragraphs 0010 to 0011, the capacitance of a capacitor that operates some of the switches constituting the switch group when the supply of power from the power supply is stopped is the above-described one. It may have a small capacity capable of storing electric power for operating the switches of the unit. Therefore, the motor control device can be further reduced in size and cost.

JP 2013-162578 A

  By the way, as described in paragraph 0025 and paragraph 0041, the power supply stop connection switch described in Patent Document 1 is a circuit that self-holds the B contact of the mechanical relay with the power supplied from the power source. Have. This switch is a type that opens when power from the power source is supplied, and shorts when power is not supplied, and can be switched on without power when the power source is turned off. For this reason, a brake function can be exhibited, without supplying electric power to the drive circuit which electrically brakes a motor.

  However, a mechanical relay such as the connection switch when the power supply is stopped is expensive. Furthermore, since the mechanical relay includes a switch having a movable structure and an exciting coil that drives the switch, it is difficult to reduce the size.

  In addition, such a fan brake function is desired to operate in a situation where power is not supplied. Further, as described in paragraph 0005 of Patent Document 1, it is desired to reduce the capacitance of the capacitor in order to reduce the size of the device.

  The present invention has been made in view of the above situation, and a motor drive control device capable of expecting a reliable brake operation when power supply is stopped without requiring a large-capacity capacitor or a mechanical relay, and the same It is an object to provide a fan motor system including

The motor drive control device of the present invention has an inverter circuit that drives each excitation coil of the electric motor. It also monitors the voltage of the power supply line, and a control unit for outputting a control signal, a switching element control terminal connected to the output terminal of the control unit, the other is connected to one end of the output terminal of one end of the switching element A capacitor having an end connected to the ground, an anode side connected to one end of the capacitor , a cathode side connected to each control input terminal of the plurality of lower arm switches, and an input side connected to one end of the capacitor It is connected, and a switching circuit connected between the output side and the output terminal of the drive circuit and the control input terminal of each of the plurality of lower arm switch, the control unit, the voltage of the power supply line is predetermined The control signal is output when the voltage drops below a value, and the switching element is turned on by the control signal from the control unit, and the switch When the winding element is turned on, the capacitor voltage is generated by charging the capacitor, and the capacitor voltage is supplied to the control input terminals of the plurality of lower arm switches via the plurality of rectifier elements. Each excitation coil is short-circuited by being simultaneously turned on, and each of the output terminal of the drive circuit and each of the plurality of lower arm switches performed by the switching circuit when the terminal voltage of the capacitor voltage exceeds a predetermined value. and blocking between the control input terminal, the Ru performed in conjunction.

  The fan motor system of the present invention includes the motor drive control device and the electric motor.

  According to the motor drive control device and the fan motor system including the motor drive control device of the present invention, a reliable brake operation can be expected when power supply is stopped without requiring a large-capacity capacitor or a mechanical relay.

1 is an electric circuit diagram illustrating a configuration of a motor drive control device and a fan motor system including the same in an embodiment of the present invention. It is a time chart which shows the signal waveform of the principal part in a circuit.

Embodiments of the present invention will be described below with reference to the drawings.
<Apparatus and system configuration>
<Description of basic configuration and operation>
FIG. 1 shows a configuration example of an electric circuit of a motor drive control device and a fan motor system including the motor drive control device according to an embodiment of the present invention.

  In the fan motor system shown in FIG. 1, the electric motor M rotationally drives a fan for air blowing (not shown). The electric motor M includes three-phase exciting coils Lu, Lv, and Lw of U phase, V phase, and W phase. The fan motor system also includes a motor drive control device 1 and a hall element 7 (rotation sensor).

  The motor drive control device 1 incorporates an inverter, converts DC power supplied from the power source 2 into AC and supplies the AC to the electric motor M. The motor drive control device 1 is connected to the three-phase exciting coils Lu, Lv, Lw of the electric motor M via terminals 21-23. The motor drive control device 1 controls the rotation of the rotor of the electric motor M.

  The power source 2 outputs a predetermined DC power source voltage required for the motor drive control device 1 and the electric motor M to operate, for example, +12 [V]. The power supply voltage output from the power supply 2 is applied to the power supply line 31 of the motor drive control device 1 as the input voltage Vin.

  The hall element 7 is a rotation sensor. That is, the Hall element 7 is disposed in the vicinity of the output shaft of the electric motor M, detects the rotation of the rotor of the electric motor M, and outputs a rotation detection signal S10 corresponding to the rotation to the drive circuit 4 (not shown). ). A power supply voltage necessary for the operation of the Hall element 7 is applied to the power supply terminal 7a.

  The motor drive control device 1 is provided with an inverter circuit 11 for controlling energization of the excitation coils Lu, Lv, Lw of the electric motor M. The inverter circuit 11 is composed of six transistors Q1 to Q6. These transistors Q1 to Q6 are all MOS (metal-oxide-semiconductor) type field-effect transistors (FETs).

  A switching leg in which the transistor Q1 and the transistor Q4 are connected in series is connected between the power supply line 31 and the ground 32. A switching leg in which the transistor Q2 and the transistor Q5 are connected in series is connected between the power supply line 31 and the ground 32. A switching leg in which the transistor Q3 and the transistor Q6 are connected in series is connected between the power supply line 31 and the ground 32.

  Transistors Q 1, Q 2, and Q 3 are upper arm side switches connected to the power supply line 31, and transistors Q 4, Q 5, and Q 6 are lower arm side switches connected to the ground 32.

  A location where the source terminal of the transistor Q1 and the drain terminal of the transistor Q4 are connected is connected to the exciting coil Lu via the terminal 22. A location where the source terminal of the transistor Q2 and the drain terminal of the transistor Q5 are connected is connected to the exciting coil Lv via the terminal 23. A location where the source terminal of the transistor Q3 and the drain terminal of the transistor Q6 are connected is connected to the exciting coil Lw via the terminal 21.

  Therefore, when the transistor Q1 on the upper arm side is turned on (conductive state), current can be supplied from the power line 31 on the upper arm side to the exciting coil Lu via the terminal 22. Further, when the transistor Q2 on the upper arm side is turned on, a current can be supplied from the power supply line 31 to the exciting coil Lv via the terminal 23. Further, when the transistor Q3 on the upper arm side is turned on, a current can be supplied from the power supply line 31 to the exciting coil Lw via the terminal 21.

  Further, when the transistor Q4 on the lower arm side is turned on, a current can be drawn from the terminal 22 connected to the exciting coil Lu to the ground 32. Further, when the transistor Q5 on the lower arm side is turned on, a current can be drawn from the terminal 23 connected to the exciting coil Lv to the ground 32. Further, when the transistor Q6 on the lower arm side is turned on, a current can be drawn from the terminal 21 connected to the exciting coil Lw to the ground 32.

  The transistors Q1 to Q6 are controlled so that no through current flows through the switching legs. That is, the transistors Q1 and Q4 connected in series are controlled so as not to be turned on simultaneously, the transistors Q2 and Q5 connected in series are controlled not to be turned on simultaneously, and the transistors Q3 and Q6 connected in series are controlled. It is controlled not to turn on at the same time.

  By sequentially turning on a pair of any one of the transistors Q1 to Q3 on the upper arm side and any one of the transistors Q4 to Q6 on the lower arm side, the three-phase exciting coils Lu, Lv, and Lw are sequentially turned on. The electric motor M can be energized to rotationally drive the electric motor M.

  Drive signals Su, Sv, Sw, Sx, Sy, and Sz for controlling on / off of the transistors Q1 to Q6, respectively, are output from the drive circuit 4 and applied to the gate terminals that are the control input terminals of the transistors Q1 to Q6. Is done.

  That is, the transistor Q1 is turned on / off according to the drive signal Su that is a binary signal, the transistor Q2 is turned on / off according to the drive signal Sv, and the transistor Q3 is turned on / off according to the drive signal Sw. Further, the transistor Q4 is turned on / off according to the drive signal Sx, the transistor Q5 is turned on / off according to the drive signal Sy, and the transistor Q6 is turned on / off according to the drive signal Sz.

  As shown in FIG. 1, a switching circuit 6 is provided between the output terminal of the drive circuit 4 and the control input terminals of the transistors Q4 to Q6. As will be described later, when the electric motor M is driven, the inside of the switching circuit 6 is in a conductive state, so that the drive signals Sx, Sy, Sz output from the drive circuit 4 are applied to the transistors Q4 to Q6 as they are.

  The drive circuit 4 sequentially switches the states of the drive signals Su, Sv, Sw, Sx, Sy, and Sz according to the rotation detection signal S10 in accordance with the drive instruction signal S2 output from the control unit 5. According to these drive signals Su, Sv, Sw, Sx, Sy, and Sz, the transistors Q1 to Q6 are turned on and off, and energization of the exciting coils Lu, Lv, and Lw is controlled, so that the rotor of the electric motor M moves in a predetermined direction. It rotates and the fan rotates. The drive circuit 4 is connected to the control power supply circuit 3 by a constant voltage power supply line 33 and is supplied with power.

  The drive instruction signal S2 is active low (Low during normal motor driving). In the configuration of FIG. 1, signals common to the drive instruction signal S2 are used as the control signal S1 and the cutoff instruction signal S3. The control signal S1 and the cutoff instruction signal S3 are active low. The control signal S1, the drive instruction signal S2, and the shut-off instruction signal S3 can be output from the control unit 5 as separate signals, but by sharing the output terminals, the circuit configuration is simplified. Can be Moreover, you may provide the control part 5 with respect to each signal. The control unit 5 that outputs the drive instruction signal S2 can be configured using, for example, a microcomputer or a logic circuit that executes a predetermined operation.

  In order to generate a stable predetermined power supply voltage (for example, +5 [V]) required by the drive circuit 4, the control unit 5, and the Hall element 7 as a power supply, the control power supply circuit 3 is provided inside the motor drive control device 1. Is provided. The control power supply circuit 3 generates a predetermined power supply voltage based on the input voltage Vin, supplies it to the drive circuit 4 and the control unit 5 via the output-side constant voltage power supply line 33, and passes through the constant voltage power supply line 34. Supply to the Hall element 7. The control power supply circuit 3 includes, for example, a smoothing capacitor (not shown) and smoothes a predetermined power supply voltage.

<Description of configuration related to brake function of electric motor M>
The control unit 5 shown in FIG. 1 has a function of monitoring a voltage drop of the input voltage Vin. That is, the control unit 5 compares the input voltage Vin with a predetermined threshold value V2 (predetermined value) to identify whether or not the supply of power is stopped (see FIG. 2A). In the configuration of FIG. 1, the input voltage Vin is divided by a voltage dividing circuit constituted by resistors R4 and R5, and the control unit 5 monitors the divided voltage. The control unit 5 may monitor the output voltage drop of the control power supply circuit 3 supplied to the control unit 5 instead of monitoring the input voltage Vin.

  The capacitor C1 accumulates charges such as a smoothing capacitor (not shown) of the control power supply circuit 3 when the supply of the power supply is stopped, and outputs a capacitor voltage Vc necessary for brake control.

  Capacitor C1 has one end connected to the emitter terminal of switching element Q7 and the other end connected to ground 32. The switching element Q7 is an NPN type transistor. The collector terminal of the switching element Q7 is connected to the constant voltage power line 33. The base terminal, which is the control input terminal of the switching element Q7, is connected to the output of the control unit 5 so that the control signal S1 is input.

  The control unit 5 monitors the input voltage Vin, and switches the control signal S1 to a high level at least temporarily as shown in FIG. 2B when the input voltage Vin becomes equal to or lower than the threshold value V2 due to the stop of power supply. When the control signal S1 is at a high level, the switching element Q7 is turned on, current flows instantaneously from the constant voltage power supply line 33 to the capacitor C1 via the switching element Q7, and charges are accumulated in the capacitor C1. That is, the switching element Q7 applies the output voltage of the control power supply circuit 3 to one end of the capacitor C1 when turned on.

  The capacitor voltage Vc, which is the terminal voltage of the capacitor C1, rapidly rises as shown in FIG. 2 (c) described later when the switching element Q7 is turned on, and thereafter gradually with the discharge of the charge from the capacitor C1. To drop. The discharge speed changes according to the capacitance of the capacitor C1 and the load-side impedance.

  One end of the capacitor C1 and the control input terminals (gate terminals) of the transistors Q4 to Q6 are connected via three rectifier elements D1, D2, and D3, respectively. The rectifying elements D1, D2, and D3 are diodes.

  The rectifying element D1 is connected in a direction that allows current to pass from the capacitor C1 toward the control input terminal of the transistor Q4, and supplies the terminal voltage of the capacitor C1 to the control input terminal of the transistor Q4. The rectifier element D2 is connected in such a direction as to allow current to pass from the capacitor C1 toward the control input of the transistor Q5, and supplies the terminal voltage of the capacitor C1 to the control input terminal of the transistor Q5. The rectifying element D3 is connected in a direction that allows current to pass from the capacitor C1 toward the control input of the transistor Q6, and supplies the terminal voltage of the capacitor C1 to the control input terminal of the transistor Q6.

  Therefore, when the capacitor C1 is charged and the capacitor voltage Vc is sufficiently high, the capacitor voltage Vc is applied to the control input terminals of the transistors Q4 to Q6 via the rectifying elements D1 to D3. When the capacitor voltage Vc is sufficiently high, the transistors Q4 to Q6 are simultaneously turned on.

  When the three transistors Q4 to Q6 are both turned on, the terminals 21, 22, and 23 are grounded to the common ground 32 via the transistors Q4 to Q6, so that a circuit that short-circuits the three excitation coils Lu, Lv, and Lw Is formed. A short brake is applied so that the rotation of the electric motor M stops rapidly due to a short circuit of the excitation coils Lu, Lv, Lw.

  That is, when the supply of power from the power source 2 is stopped, the control unit 5 detects a decrease in the input voltage Vin and turns on the switching element Q7, so that the capacitor C1 is charged, as shown in FIG. A capacitor voltage Vc is generated. The capacitor voltage Vc is applied to the control input terminals of the transistors Q4 to Q6 to form a circuit for short-circuiting the exciting coils Lu, Lv, Lw, and the electric motor M is braked for rotation.

  When the transistors Q4 to Q6 are turned on at the same time, it may be necessary to control all the transistors Q1 to Q3 on the upper arm side to be turned off. In that case, the drive circuit 4 controls the drive signals Su, Sv, and Sw so that the transistors Q1 to Q3 are turned off in accordance with the drive instruction signal S2 output from the control unit 5. Further, in order to suppress the current consumption of the drive circuit 4, the output signals for the transistors Q4 to Q6 are also set to the low level.

  In this embodiment, since the transistors Q4 to Q6 are MOS field effect transistors, the input impedances of these control input terminals (gate terminals) are very large. Therefore, the current flowing from one end of the capacitor C1 to the transistors Q4 to Q6 via the rectifying elements D1 to D3 is very small.

  Therefore, the rate of decrease of the capacitor voltage Vc becomes very slow, and the transistors Q4 to Q6 can be kept on for a relatively long time.

<Function to suppress discharge of charge from capacitor C1>
However, when the control input terminals of the transistors Q4 to Q6 and the output terminals of the drive circuit 4 are connected, the output terminal of the drive circuit 4 passes through the rectifier elements D1 to D3 from one end of the capacitor C1. Current flows to the side. For this reason, the capacitor C1 may be discharged in a short time.

  In order to prevent excessive discharge from the capacitor C1 as described above, a switching circuit 6 is provided in the motor drive control device 1 shown in FIG. The switching circuit 6 in FIG. 1 includes one supply switching switching element Q8 and three signal cutting switching elements Q9 to Q11. The supply switching element Q8 is an NPN transistor, and each of the signal cut switching elements Q9 to Q11 is a MOS field effect transistor. The switching circuit 6 cuts off the output terminal of the drive circuit 4 and the control input terminals of the lower-arm transistors Q4 to Q6 when the terminal voltage of the capacitor C1 is equal to or higher than a predetermined value.

The signal disconnect switching element Q9 has a source terminal connected to the output terminal of the drive circuit 4, and a drain terminal connected to the control input terminal of the transistor Q4. The parasitic diode of the signal cut switching element Q9 allows passage only in the direction from the output terminal of the drive circuit 4 toward the control input terminal of the transistor Q4. As a result, the signal cut switching element Q9 blocks the current from flowing from the control input terminal of the transistor Q4 to the output terminal of the drive circuit 4. Thereby, it can suppress that an electric current flows out from the capacitor | condenser C1 to the output terminal of the drive circuit 4 via the rectifier D1.
Similarly, the signal cut switching element Q10 has a source terminal connected to the output terminal of the drive circuit 4, and a drain terminal connected to the control input terminal of the transistor Q5. The parasitic diode of the signal cut switching element Q10 allows passage only in the direction from the output terminal of the drive circuit 4 toward the control input terminal of the transistor Q5. As a result, the signal cut switching element Q10 blocks the current from the control input terminal of the transistor Q5 to the output terminal of the drive circuit 4 so as not to flow. Thereby, it can suppress that an electric current flows out from the capacitor | condenser C1 to the output terminal of the drive circuit 4 via the rectifier D2.
The signal disconnect switching element Q11 has a source terminal connected to the output terminal of the drive circuit 4 and a drain terminal connected to the control input terminal of the transistor Q6. The parasitic diode of the signal cut switching element Q11 allows passage only in the direction from the output terminal of the drive circuit 4 toward the control input terminal of the transistor Q6. As a result, the signal cut switching element Q11 blocks the current from the control input terminal of the transistor Q6 to the output terminal of the drive circuit 4 so as not to flow. Thereby, it can suppress that an electric current flows out from the capacitor | condenser C1 to the output terminal of the drive circuit 4 via the rectifier D3.

  The supply switching element Q8 generates a switch signal Vq. This switch signal Vq is applied to each control input terminal (gate terminal) of the three signal disconnect switching elements Q9 to Q11.

  The supply switching switching element Q8 has an emitter terminal connected to the ground 32, a collector terminal connected to the control input terminals (gate terminals) of the signal cutting switching elements Q9 to Q11, and a constant voltage power line via a resistor R1. 33. Further, the base terminal is connected to one end of the capacitor C1 via the resistor R2. A resistor R3 is connected between the base terminal and the emitter terminal of the supply switching element Q8.

  Accordingly, the supply switching element Q8 is turned on / off according to the capacitor voltage Vc, and a voltage according to the on / off state of the supply switching element Q8 is output as the switch signal Vq. That is, when the capacitor voltage Vc is low, the supply switching element Q8 is turned off, and the switch signal Vq is equal to the voltage of the constant voltage power supply line 33. Further, when the capacitor voltage Vc is high, the supply switching element Q8 is turned on, and the switch signal Vq is at a low level as shown in FIG.

  Each of the signal disconnection switching elements Q9 to Q11 is turned on (conductive state) when the voltage of the switch signal Vq applied to the control input terminal is high, and is turned off (cut off state) when the voltage of the switch signal Vq is low.

  That is, when the input voltage Vin is normal in the vicinity of the voltage V1 and the electric motor M is in a normal operation state, the capacitor voltage Vc is low, the supply switching element Q8 is off, and the constant voltage power source is connected via the resistor R1. When the voltage of the line 33 is applied, the voltage of the switch signal Vq is increased. Thereby, the signal cut switching elements Q9 to Q11 are turned on, and the drive signals Sx, Sy, and Sz output from the drive circuit 4 are applied to the control input terminals of the transistors Q4 to Q6.

  Further, when the power supply from the power supply 2 is stopped, the input voltage Vin decreases, the switching element Q7 is turned on, the capacitor C1 is charged, and the capacitor voltage Vc increases. Then, the supply switching switching element Q8 is turned on, the voltage of the switch signal Vq is lowered, and the signal disconnection switching elements Q9 to Q11 are switched to the cutoff state.

  As a result, the current due to the electric charge accumulated in the capacitor C1 flows to the control input terminals of the transistors Q4 to Q6 through the rectifying elements D1 to D3, but is blocked by the switching circuit 6 and therefore to the output terminal of the drive circuit 4. Does not flow. Therefore, the state where the voltage of the capacitor voltage Vc is high can be maintained for a long time. When the capacitor voltage Vc is high, the transistors Q4 to Q6 are kept on, so that the short-circuited state of the exciting coils Lu, Lv, and Lw can be maintained for a long time.

<Power consumption suppression function>
By the way, in the motor drive control device 1, the circuit that applies the brake by short-circuiting the excitation coils Lu, Lv, and Lw is required while the capacitor voltage Vc of the capacitor C1 is sufficiently high without supplying power from the outside. Works correctly. That is, even after the power supply from the output of the power supply 2 is stopped, the electric motor M can be short-brake.

  However, for example, if the load driven by the control power supply circuit 3 is large and the voltage appearing on the constant voltage power supply line 33 decreases in a very short time, the charging operation to the capacitor C1 may fail. Conceivable.

  For example, after the power supply of the power supply 2 is stopped, the control unit 5 detects the decrease in the input voltage Vin and supplies the control signal S1 to the switching element Q7. When the power supply is stopped, the capacitor C1 cannot be charged. Further, when the time for which the switching element Q7 is turned on is extremely short, the capacitor voltage Vc does not rise sufficiently, so that the transistors Q4 to Q6 are not turned on and the exciting coils Lu, Lv, Lw cannot be short-circuited. .

  In order to prevent the charging failure of the capacitor C1 as described above, it is necessary that there is a time margin from when the power supply of the input voltage Vin stops until the voltage of the constant voltage power supply line 33 decreases. is there. For this purpose, it is necessary to reduce the load driven by the control power supply circuit 3 as much as possible.

  In the motor drive control device 1 shown in FIG. 1, a cut-off switch SW1 for cutting off this path is connected between the constant voltage power supply line 34 output from the control power supply circuit 3 and the power supply terminal 7a of the Hall element 7. It is. The cutoff switch SW1 is a switch that can be controlled from the outside, and the on / off state is switched by a cutoff instruction signal S3 output from the control unit 5.

  In the normal operation state of the electric motor M, the cutoff instruction signal S3 is at a low level. At this time, the cutoff switch SW1 is turned on in accordance with the cutoff instruction signal S3, and the constant voltage power line 34 is connected from the output of the control power circuit 3. Electric power is supplied to the Hall element 7 through it. That is, the Hall element 7 is one of loads that the control power supply circuit 3 drives.

  On the other hand, when the control unit 5 detects a voltage drop of the input voltage Vin, the control unit 5 switches the cutoff instruction signal S3 to be output to a high level and switches the cutoff switch SW1 to an off (shutoff) state. When the cut-off switch SW1 is turned off, power supply from the constant voltage power supply line 34 to the Hall element 7 is stopped. Then, the voltage drop rate in the constant voltage power supply line 33 on the output side of the control power supply circuit 3 is slowed by the amount that the useless power supply to the Hall element 7 is stopped, and the control unit 5 and the switching element Q7 are activated. The time margin increases. Thereby, the charging failure of the capacitor C1 as described above can be prevented. It should be noted that the load driven by the control power supply circuit 3 can also be reduced by stopping the operation of the drive circuit 4 by the drive instruction signal S2.

  Signal waveforms of main parts in the circuit of FIG. 1 are shown in FIGS. FIG. 2A is a waveform diagram showing changes in the input voltage Vin. FIG. 2B is a waveform diagram showing changes in the control signal S1. FIG. 2C is a waveform diagram showing changes in the capacitor voltage Vc. FIG. 2D is a waveform diagram showing changes in the switch signal Vq. 2A, 2B, 2C, and 2D, the horizontal axis represents a common time axis, and the vertical axis represents voltage [V]. Represent. The control signal S1 and the switch signal Vq are binary signals that are either low level or high level voltage. Time t0 shown on the time axis corresponds to the time when the input voltage Vin drops from the normal voltage V1 to the threshold value V2. The time t1 shown on the time axis corresponds to the time when the input voltage Vin becomes 0 [V]. In the change of the capacitor voltage Vc in FIG. 2C, the section of the attenuation curve after being charged at the time t0 and reaching the peak voltage means that the charge accumulated in the capacitor C1 is discharged.

  As shown in FIG. 2A, when the input voltage Vin decreases from the normal voltage V1 and becomes equal to or lower than the threshold value V2 (time t0), the control signal S1 becomes high level as shown in FIG. Then, the switching element Q7 is turned on, the capacitor C1 is charged, and the capacitor voltage Vc rapidly increases as shown in FIG. Further, the drive circuit 4 stops its operation in response to a drive instruction signal S2 (not shown) common to the control signal S1. The supply of power to the Hall element 7 is stopped by the cutoff instruction signal S3 that is common to the control signal S1. Further, since the switch signal Vq is switched to the low level at time t0 as shown in FIG. 2D, the signal disconnect switching elements Q9 to Q11 are turned off. The control signal S1 may change to a low level after the charging of the capacitor C1 is completed.

<Modification>
Various modifications of the configuration of the motor drive control device 1 shown in FIG. 1 can be considered as described below.

  For the transistors Q1 to Q6, it is possible to use a semiconductor switching device other than the MOS type FET. However, for the transistors Q4 to Q6, it is desirable to adopt a MOS type FET in order to increase the impedance of the control input terminal. Moreover, you may employ | adopt IGBT (Insulated Gate Bipolar Transistor).

  The Hall element 7 can be replaced with other sensors. In the configuration of FIG. 1, the cutoff switch SW <b> 1 blocks only the power supply path to the hall element 7, but it can be changed so as to simultaneously block other power supply paths.

  For the signal cut switching elements Q9 to Q11, a semiconductor switching device other than a MOS FET may be used, or a relay may be used instead. For the switching element Q7 and the supply switching element Q8, a semiconductor switching device other than the NPN transistor may be used.

  The electric motor M can be replaced with various types of motors other than the three-phase motor. Further, the circuit of the motor drive control device 1 may be partially or entirely configured as an integrated circuit (IC).

The characteristic items included in the motor drive control device 1 and the fan motor system described above are listed below.
According to the motor drive control device 1 described above, since the control unit 5 outputs the control signal S1, it is necessary to reliably charge the capacitor C1 and apply the brake when the power supply from the power source 2 is stopped. A capacitor voltage Vc can be generated.

  According to the motor drive control device 1 described above, since the voltage output from the control power supply circuit 3 is used, the capacitor C1 can be reliably charged. Furthermore, even after the voltage Vin supplied from the original power supply 2 is lowered, a sufficiently high voltage is output from the control power supply circuit 3 for a while, so that a reliable braking operation is possible. Further, in the steady state, the capacitor C1 is not charged, so that no noise is generated and the life is long.

  According to the motor drive control device 1 described above, by providing the cut-off switch SW1, the load of the control power supply circuit 3 can be cut off when the power supply from the power supply 2 is stopped. Can be delayed. Therefore, the control unit 5 that operates according to the output voltage of the control power supply circuit 3 can have a time margin for realizing a reliable brake operation.

  According to the motor drive control device 1 described above, the control unit 5 outputs the shut-off instruction signal S3. Therefore, when the power supply from the power source 2 is stopped, the shut-off switch SW1 is reliably shut off, and the extra element by the hall element 7 is used. Power consumption can be stopped.

  According to the motor drive control device 1 described above, the switching circuit 6 is provided with the signal cutting switching elements Q9 to Q11 and the supply switching switching element Q8, so that the driving circuit 4 is disconnected from the output of the capacitor C1. Can be delayed. As a result, the braking operation can be continued for a sufficiently long time.

  According to the motor drive control device 1 described above, MOS field effect transistors are employed for the lower arm transistors Q4 to Q6. Since the impedance at the control input terminals of these transistors Q4 to Q6 is very high, the discharge of the capacitor C1 can be delayed. As a result, the braking operation can be continued for a sufficiently long time.

DESCRIPTION OF SYMBOLS 1 Motor drive control apparatus 2 Power supply 3 Control power supply circuit 4 Drive circuit 5 Control part 6 Switching circuit 7 Hall element (an example of a rotation sensor)
7a Power supply terminal 11 Inverter circuits 21, 22, 23 Terminal 31 Power line 32 Ground 33, 34 Constant voltage power line Vin Input voltage Vc Capacitor voltage Vq Switch signals Su, Sv, Sw, Sx, Sy, Sz Drive signals Q1, Q2 , Q3 transistor (example of upper arm switch)
Q4, Q5, Q6 transistors (an example of a lower arm switch)
Q7 switching element Q8 supply switching switching element Q9, Q10, Q11 signal cutting switching element C1 capacitors D1, D2, D3 rectifier element M electric motors Lu, Lv, Lw exciting coils R1, R2, R3, R4, R5 resistor SW1 cutoff switch S1 Control signal S2 Drive instruction signal S3 Shut off instruction signal

Claims (10)

An inverter circuit including a plurality of upper arm switches for supplying current from a power supply line to a plurality of terminals connected to the respective excitation coils of the electric motor; and a plurality of lower arm switches for drawing current from the plurality of terminals; A drive circuit for supplying a drive signal for controlling the upper arm switch and the lower arm switch to each control input terminal of the circuit,
A controller that monitors the voltage of the power supply line and outputs a control signal;
A switching element having a control terminal connected to the output terminal of the control unit ;
A capacitor having one end connected to one end of the output terminal of the switching element and the other end connected to the ground ;
A plurality of rectifier elements having an anode side connected to one end of the capacitor and a cathode side connected to each control input terminal of the plurality of lower arm switches;
A switching circuit having an input side connected to one end of the capacitor and an output side connected between an output terminal of the drive circuit and a control input terminal of each of the plurality of lower arm switches ;
The control unit outputs the control signal when the voltage of the power supply line drops below a predetermined value,
The switching element is turned on by the control signal from the control unit,
When the switching element is turned on, the capacitor voltage is generated by charging the capacitor, and the capacitor voltage is supplied to the control input terminals of each of the plurality of lower arm switches through the plurality of rectifier elements. Each of the exciting coils by simultaneously turning on, and each of the output terminal of the drive circuit and the plurality of lower arm switches performed by the switching circuit when the terminal voltage of the capacitor voltage exceeds a predetermined value. Interlocking with the control input terminal of the
The motor drive control apparatus characterized by the above-mentioned. The control unit switches on the switching element by outputting the control signal at least temporarily when the voltage of the power supply line or the voltage supplied to the control unit drops below the predetermined value. The
The motor drive control device according to claim 1. A control power supply circuit for generating a constant voltage based on the output voltage of the power supply line,
When the switching element is turned on, the switching element applies the output voltage of the control power supply circuit to one end of the capacitor.
The motor drive control device according to claim 1, wherein the motor drive control device is a motor drive control device. A rotation sensor that operates based on an output voltage of the control power supply circuit and detects a rotation state of the electric motor;
A cutoff switch disposed in a power supply path from the output of the control power supply circuit to the rotation sensor,
The cutoff switch shuts off the power supply path according to a predetermined cutoff instruction signal when the output voltage of the power supply line drops below the predetermined value.
The motor drive control apparatus according to claim 3. A control unit that generates the shut-off instruction signal for shutting off the shut-off switch when the output voltage of the power supply line drops below the predetermined value;
The motor drive control device according to claim 4. The switching circuit is
A signal disconnect switching element connected between an output of the drive circuit and a control input terminal of the plurality of lower arm switches;
A supply switching element connected to a control input terminal of the capacitor and connected between the control input terminal of the signal disconnecting switching element and a ground terminal;
The motor drive control device according to any one of claims 1 to 5, wherein the motor drive control device is a motor drive control device.   An inverter circuit including a plurality of upper arm switches for supplying current from a power supply line to a plurality of terminals connected to the respective excitation coils of the electric motor; and a plurality of lower arm switches for drawing current from the plurality of terminals; A drive circuit for supplying a drive signal for controlling the upper arm switch and the lower arm switch to each control input terminal of the circuit,
  A switching element that turns on when the voltage of the power supply line drops below a predetermined value;
  One end of the capacitor is connected to the switching element, and stores a charge input via the switching element when the switching element is turned on,
  A plurality of rectifying elements for supplying terminal voltages of the capacitors to control input terminals of the plurality of lower arm switches;
  A switching circuit that shuts off between the output terminal of the drive circuit and the control input terminal of each of the plurality of lower arm switches when the terminal voltage of the capacitor is equal to or higher than a predetermined value;
  A control unit that outputs a control signal for turning on the switching element, at least temporarily, when the voltage of the power supply line or the voltage supplied to the power supply line drops below the predetermined value;
  A control power supply circuit for generating a constant voltage based on the output voltage of the power supply line;
  A rotation sensor that operates based on an output voltage of the control power supply circuit and detects a rotation state of the electric motor;
  A cutoff switch disposed in a power supply path from the output of the control power supply circuit to the rotation sensor,
  When the switching element is turned on, the switching element applies the output voltage of the control power supply circuit to one end of the capacitor,
  The cutoff switch shuts off the power supply path according to a predetermined cutoff instruction signal when the output voltage of the power supply line drops below the predetermined value.
The motor drive control apparatus characterized by the above-mentioned.   An inverter circuit including a plurality of upper arm switches for supplying current from a power supply line to a plurality of terminals connected to the respective excitation coils of the electric motor; and a plurality of lower arm switches for drawing current from the plurality of terminals; A drive circuit for supplying a drive signal for controlling the upper arm switch and the lower arm switch to each control input terminal of the circuit,
  A switching element that turns on when the voltage of the power supply line drops below a predetermined value;
  One end of the capacitor is connected to the switching element, and stores a charge input via the switching element when the switching element is turned on,
  A plurality of rectifying elements for supplying terminal voltages of the capacitors to control input terminals of the plurality of lower arm switches;
  A switching circuit that shuts off between the output terminal of the drive circuit and the control input terminal of each of the plurality of lower arm switches when the terminal voltage of the capacitor is equal to or higher than a predetermined value;
  A control power supply circuit for generating a constant voltage based on the output voltage of the power supply line;
  A rotation sensor that operates based on an output voltage of the control power supply circuit and detects a rotation state of the electric motor;
  A cutoff switch disposed in a power supply path from the output of the control power supply circuit to the rotation sensor,
  When the switching element is turned on, the switching element applies the output voltage of the control power supply circuit to one end of the capacitor,
  The cutoff switch shuts off the power supply path according to a predetermined cutoff instruction signal when the output voltage of the power supply line drops below the predetermined value.
The motor drive control apparatus characterized by the above-mentioned.   An inverter circuit including a plurality of upper arm switches for supplying current from a power supply line to a plurality of terminals connected to the respective excitation coils of the electric motor; and a plurality of lower arm switches for drawing current from the plurality of terminals; A drive circuit for supplying a drive signal for controlling the upper arm switch and the lower arm switch to each control input terminal of the circuit,
  A switching element that turns on when the voltage of the power supply line drops below a predetermined value;
  One end of the capacitor is connected to the switching element, and stores a charge input via the switching element when the switching element is turned on,
  A plurality of rectifying elements for supplying terminal voltages of the capacitors to control input terminals of the plurality of lower arm switches;
  A switching circuit that cuts off between the output terminal of the drive circuit and each control input terminal of the plurality of lower arm switches when the terminal voltage of the capacitor is equal to or higher than a predetermined value;
  The switching circuit is
  A signal disconnect switching element connected between an output of the drive circuit and a control input terminal of the plurality of lower arm switches;
  A supply switching element connected to a control input terminal of the capacitor and connected between the control input terminal of the signal disconnecting switching element and a ground terminal;
The motor drive control apparatus characterized by the above-mentioned. A fan motor system comprising the motor drive control device according to any one of claims 1 to 9 and the electric motor.

Images