JP2008061526A - Frost-protective fan system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a frost-protective fan system enabling more effective utilization of frost-protective fans and improvement in utilization efficiency of electric power. <P>SOLUTION: The frost-protective fan system is provided with a plurality of frost-protective fans 2,000, and a control and management device 3,000 for managing movement of the frost-protective fans. The control and management device 3,000 has a plurality of movement-controlling modes comprising a frost-protecting mode where the frost-protective fans 2,000 are used for frost protection, and a power-generating mode where the frost-protective fans 2,000 are used as power generators. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a defrost fan system for preventing field frost.

  In fields such as orchards and tea plantations, frost falling on the fields in winter can cause significant damage to crops. Therefore, conventionally, efforts have been made to prevent frost by installing frost-proof fans on the entire field at intervals of approximately 10 m square.

JP 2002-315451 A

  However, the usage period of the frost-proof fan is an operation period of 1 to 2 weeks per year. Except for this operation period, there is no purpose of use at all, and it was left unattended. In addition, the fields and the like were also used as wind passages, and when they were not in operation, they were always left in an idling state due to the wind.

  An object of this invention is to provide the technique which can utilize a defrost fan more effectively and can improve the utilization efficiency of electric power.

In order to achieve the above object, a defrost fan system according to the present invention comprises:
A plurality of anti-frost fans,
A control management device for managing the operation of the plurality of defrost fans;
With
The control management device has a plurality of operation control modes including a defrost mode using the defrost fan for defrosting and a power generation mode using the defrost fan as a generator.

  According to this system, when the defrost fan is not used for defrosting, the defrost fan can be used as a generator, so that the defrost fan can be used more effectively and the power use efficiency can be improved. Can do.

In the above anti-frost fan system,
Each anti-frost fan has a brushless motor,
The brushless motor is
a coil array having an m-phase (m is an integer of 3 or more) electromagnetic coil group;
A magnet array having a plurality of permanent magnets;
Among the m-phase electromagnetic coil groups, n magnetic sensors associated with an n-phase (n is an integer less than or equal to 2 and less than m) electromagnetic coil group, the relative positions of the magnet row and the coil row N magnetic sensors for detecting
A drive control circuit for controlling power supply to the coil array by using sensor outputs of the n magnetic sensors;
A regeneration control circuit for controlling regeneration of electric power from the coil array, using sensor outputs of the n magnetic sensors;
With
The drive control circuit includes:
Generating n sets of drive signals for the n-phase electromagnetic coil groups associated with the n magnetic sensors using the sensor outputs of the n magnetic sensors;
One of the sensor outputs of the n magnetic sensors is set to (mn) sets of drive signals for an (mn) phase electromagnetic coil group not associated with the n magnetic sensors. Generate using each of the above,
The regeneration control circuit is
Generating n sets of regenerative control signals for the n-phase electromagnetic coil groups associated with the n magnetic sensors using the sensor outputs of the n magnetic sensors;
(Mn) sets of regenerative control signals for the (mn) phase electromagnetic coil groups not associated with the n magnetic sensors are represented by one of the sensor outputs of the n magnetic sensors. You may make it produce | generate using two or more, respectively.

  According to this configuration, m sets of drive signals and regenerative control signals are generated using n magnetic sensors smaller than the number m of phases of the electromagnetic coil group, and therefore there is an error or variation in the sensor output of each sensor. In addition, the phase of the drive signal for each phase and the phase of the regenerative control signal for each phase can be more matched. As a result, it is possible to perform frost prevention and power generation more efficiently.

The anti-frost fan system further includes
The ((n−n) simulated sensor outputs for the (mn) phase electromagnetic coil group not associated with the n magnetic sensors are represented by the sensor outputs of the n magnetic sensors. A simulated sensor output generation unit that generates based on a calculation using one or more of them as a variable,
The drive control circuit is configured for the m-phase electromagnetic coil group according to m sensor outputs including sensor outputs of the n magnetic sensors and (mn) simulated sensor outputs. Generate m sets of drive signals,
The regenerative control circuit is configured for the m-phase electromagnetic coil group according to m sensor outputs including sensor outputs of the n magnetic sensors and (mn) simulated sensor outputs. The m sets of regeneration control signals may be generated.

  According to this configuration, since a simulated sensor output corresponding to an electromagnetic coil group not provided with a magnetic sensor can be obtained, a drive signal for the electromagnetic coil group can be easily generated using this. It is.

The simulated sensor output generator is
Among the sensor outputs of the n magnetic sensors, (mn) simulated sensor outputs for the (mn) phase electromagnetic coil group not associated with the n magnetic sensors These may be generated based on an operation using two or more of them as variables.

  With this configuration, it is possible to correctly generate a simulated sensor output even if a single sensor output cannot provide a simulated sensor output.

  The simulated sensor output generation unit may generate the simulated sensor output by real time calculation using sensor outputs of the n magnetic sensors.

  When the mutual relationship between sensor outputs of m magnetic sensors corresponding to m-phase electromagnetic coil groups is given by a relatively simple function such as a trigonometric function, simulated sensor output can be easily performed using real-time computation. Can be generated.

  Alternatively, the simulated sensor output generation unit generates the simulated sensor output using a lookup table having sensor outputs of the n magnetic sensors as input values and the simulated sensor outputs as output values. It may be.

  With this configuration, it is possible to easily generate a simulated sensor output regardless of whether or not the mutual relationship between the sensor outputs of the m magnetic sensors corresponding to the m-phase electromagnetic coil group is given by a simple function. Is possible.

  The integer m may be 3, and the integer n may be 2.

  In this configuration, since only two magnetic sensors need be provided in the three-phase brushless motor, the number of magnetic sensors can be reduced to 2/3 compared to the conventional one.

  Further, the magnetic sensor may be a sensor that outputs an output signal indicating an analog change in accordance with a relative position between the magnet array and the coil array.

  In this case, it is possible to generate a regenerative control signal using the analog change of the sensor output.

  The present invention can be realized in various forms, for example, forms such as an anti-frost fan system, a brushless generator, a brushless motor, a control method (or drive method) thereof, an actuator using the same, and the like. Can be realized.

Next, embodiments of the present invention will be described in the following order.
A. Defrost system configuration and operation:
B. Overview of motor configuration and operation:
C. Configuration of drive control circuit:
D. Regenerative control circuit configuration:
E. Other examples:
F. Variation:

A. Defrost system configuration and operation:
FIG. 1 is an explanatory diagram showing the configuration of a defrost fan and a defrost fan system as an embodiment of the present invention. As shown in FIG. 1A, the defrost fan 2000 includes a brushless motor 2100, fan blades 2200, and a support 2300 that supports the brushless motor 2100. As shown in FIG. 1 (B), the defrost fan system has a plurality of defrost fans 20000 connected by a power line PL and a communication line CL. A control management device 3000 for managing the operations of the plurality of defrost fans 2000 is connected to the communication line CL.

  The control management device 3000 can be realized by a computer. The control management device 3000 operates each frost-proof fan 2000 as a blower by transmitting an operation command value (also referred to as “setting command value”) to each frost-proof fan 2000, or causes each frost-proof fan 2000 to operate. It can be operated as a generator. The mode in which each frost-proof fan 2000 is operated as a blower is referred to as “blower setting mode” or “frost-proof mode”, and the mode in which each frost-proof fan 2000 is operated as a generator is “generator setting mode” or “power generation mode”. Call it. As an operation mode of the anti-frost fan system, there is also a stop setting mode (also referred to as “stop mode”) for stopping the anti-frost fan 2000. In the stop setting mode, anti-frost fan 2000 is idling.

  FIG. 2 is a flowchart showing a control operation of the defrost fan system. In step S100, the operator of the control management device 3000 sets the mode of the defrost fan system. When the set mode is not changed from the previously set mode, the process returns from step S110 to step S100 and waits for the next mode setting. On the other hand, when the mode is changed, in steps S120 and S130, the control management device 3000 determines whether the set mode is the blower setting mode, the generator setting mode, or the stop setting mode. Determined. When the set mode is the operation mode (blower setting mode or generator setting mode), in step S170, the operation command value of the mode is transmitted from the control management device 3000 to each defrosting fan 2000 via the communication line CL. And is set in the memory or register in each anti-frost fan 2000. As a result, each anti-frost fan 2000 starts operation in the set mode. In addition, it is preferable that the operation command value in the blower setting mode includes a command value for designating the rotation speed and drive voltage value of the blower. Moreover, it is preferable that the operation command value in the generator setting mode includes a command value for designating the regeneration amount. If such an operation command value is used, it is possible to specify not only the operation mode but also the degree of operation. After executing step S170, the process returns to step S100 and waits for the next mode setting input.

  On the other hand, when the set mode is the stop setting mode, in step S180, an operation stop command value is transmitted from the control management device 3000 to each anti-frost fan 2000 via the communication line CL. When step S180 ends, the overall control ends.

  Thus, in the defrosting fan system of the present embodiment, the defrosting fan 2000 can be used for blowing air (for defrosting), and when no blowing is required, the defrosting fan 2000 is used as a generator. can do. Therefore, the defrost fan can be used more effectively.

  In the above description, the same operation mode is set for all of the plurality of defrost fans, but instead, the operation mode may be set individually for each defrost fan. In this case, an identifier (ID) is assigned to each defrosting fan in advance and registered in the control management device 3000, and this identifier is registered in advance in each defrosting fan (for example, a nonvolatile memory). Is preferred. In this configuration, since the operation mode can be designated for each individual defrost fan, it is possible to use each defrost fan more efficiently.

B. Overview of motor configuration and operation:
FIGS. 3A to 3C are cross-sectional views showing the configuration of the motor body of the brushless motor used in the defrost fan according to the embodiment of the present invention. This brushless motor has both a function as an electric motor and a function as a generator.

  The motor main body 100 includes a stator portion 10 and a rotor portion 30 whose outer shapes are substantially disk-shaped. The stator unit 10 (FIG. 3C) is provided with three sets of electromagnetic coils 11 to 13 constituting three phases on the circuit board 120 and two magnetic sensors 40A and 40B. The first magnetic sensor 40A is a sensor for the first set of coils 11, and the second magnetic sensor 40B is a sensor for the second set of coils 12. Note that a magnetic sensor for the third set of coils 13 is not mounted. Hereinafter, the three sets of electromagnetic coils 11 to 13 are referred to as “A phase coil 11”, “B phase coil 12”, and “C phase coil 13”. The magnetic sensors 40A and 40B are referred to as “A phase sensor 40A” and “B phase sensor 40B”.

  The rotor unit 30 (FIG. 3B) is provided with four magnets 32, and the central axis of the rotor unit 30 constitutes the rotation shaft 112. The magnetization direction of these magnets 32 is a direction perpendicular to the paper surface in FIG. 3B, which corresponds to the vertical direction in FIG.

  4A to 4D are explanatory views showing the positional relationship between the magnet array and the coil array during operation of the motor. As shown in FIG. 4A, the magnets 32 are arranged at a constant magnetic pole pitch Pm, and adjacent magnets are magnetized in opposite directions. Further, the two coils constituting the coil group of one phase are arranged at a constant pitch Pc and are always excited in the same direction. The adjacent phase coils are separated by 1/3 of the pitch Pc between the in-phase coils. The pitch Pc between the in-phase coils is equal to twice the magnetic pole pitch Pm. The magnetic pole pitch Pm corresponds to π in electrical angle. The electrical angle 2π is associated with a mechanical angle or distance that moves when the phase of the drive signal changes by 2π. In this embodiment, when the phase of the drive signal changes by 2π, the rotor unit 30 moves by twice the magnetic pole pitch Pm.

  FIG. 4A shows a state where the phase is 0 or 2π. FIGS. 4B to 4D show states at the time when the phases are π / 2, π, and 3π / 2, respectively. 4A and 4C, the hatching of the A-phase coil 11 is omitted because the polarity of the drive signal of the A-phase coil 11 is reversed at these timings (that is, the excitation direction is reversed). Because.

  FIG. 5 is an explanatory diagram showing an example of sensor output and drive signals during normal rotation of the motor. FIG. 5A shows the sensor output SSA of the A-phase sensor 40A and the sensor output SSB of the B-phase sensor 40B. As the sensors 40A and 40B, Hall IC sensors having an analog output can be used. FIG. 5B shows a simulated C-phase sensor output SSC (also referred to as “C-phase sensor simulation signal SSC”) synthesized from two sensor outputs SSA and SSB. A method for generating the C-phase sensor simulation signal SSC will be described later. It can be understood that the three sensor outputs SSA, SSB, and SSC constitute a beautiful three-phase signal whose phases are sequentially shifted by 2π / 3.

  FIG. 5C shows an example of a three-phase drive signal generated by PWM control using these three-phase sensor outputs SSA, SSB, and SSC. The A-phase drive signals DRVA1 and DRVA2 have effective voltages similar in shape to the A-phase sensor output SSA. The A-phase first drive signal DRVA1 is a signal that generates a pulse only when the sensor output SSA is positive, and the second drive signal DRVA2 generates a pulse only when the sensor output SSA is positive. The signals are shown together in FIG. 5C. For convenience, the second drive signal DRVA2 is drawn as a negative pulse. The same applies to the other phases.

  FIG. 6 is an explanatory diagram showing an example of the sensor output and the drive signal when the motor is reversely rotated. Similarly to FIG. 5, during reverse rotation, the C-phase sensor output SSC is synthesized from the other two-phase sensor outputs SSA and SSB, and these three sensor outputs SSA, SSB, and SSC are used to drive the three-phase drive signal. Is generated.

  Similarly, when power is regenerated from the coils 11 to 13, the C-phase sensor output SSC is synthesized from the other two-phase sensor outputs SSA and SSB, and these three sensor outputs SSA, SSB and SSC are used. Thus, a three-phase regeneration control signal is generated.

  FIG. 7 is a block diagram showing the configuration of the motor control circuit of the brushless motor of this embodiment. The motor control circuit 1000 includes a drive control circuit 200, a regeneration control circuit 300, and a CPU 400. The CPU 400 sets values in various registers in the control circuits 200 and 300 according to the operation command values received from the control management device 3000, and instructs the control values in the control circuits 200 and 300. It has a function. Below, each structure and operation | movement of the drive control circuit 200 and the regeneration control circuit 300 are demonstrated sequentially.

C. Configuration of drive control circuit:
FIG. 8A is a block diagram illustrating the configuration of the drive control circuit of the brushless motor of this embodiment. The drive control circuit 200 includes a C-phase sensor signal generation unit 230, a drive signal generation unit 240, three-phase driver circuits 250A to 250C, and an AD conversion unit 260. The two sensor outputs SSA and SSB are converted into digital multilevel signals by the AD conversion unit 260 and supplied to the C-phase sensor signal generation unit 230. The C-phase sensor signal generation unit 230 generates the C-phase sensor simulation signal SSC shown in FIG. The internal configuration of the C-phase sensor signal generation unit 230 will be described later. The drive signal generation unit 240 generates a three-phase drive signal (FIG. 5C) based on the three-phase sensor outputs SSA, SSB, and SSC. The driver circuits 250A to 250C drive the three-phase electromagnetic coil groups 11 to 13 in the motor main body 100 according to these three-phase drive signals.

  FIG. 8B shows an example of the internal configuration of the magnetic sensor 40A. The B-phase magnetic sensor 40B also has the same configuration. The magnetic sensor 40 </ b> A includes a Hall element 42, a bias adjustment unit 44, and a gain adjustment unit 46. The Hall element 42 measures the magnetic flux density X. The bias adjustment unit 44 adds the bias value b to the output X of the Hall element 42, and the gain adjustment unit 46 multiplies the gain value a. The output SSA (= Y) of the magnetic sensor 40A is given by, for example, the following formula (1) or formula (2).

Y = a · X + b (1)
Y = a (X + b) (2)

  The gain value a and the bias value b of the magnetic sensor 40A are set in the magnetic sensor 40A by the CPU 400. By setting the gain value a and the bias value b to appropriate values, the sensor output SSA can be calibrated to a preferable waveform shape. The same applies to the B-phase sensor 40B.

  In this embodiment, the magnetic sensor is mounted only for two phases (A phase and B phase) of the three-phase coil group, and the magnetic sensor is omitted for the other one phase (C phase). Each magnetic sensor can obtain a sensor output having a preferable waveform shape by appropriately setting a gain and a bias (also referred to as “offset”). However, in order to obtain sensor outputs having appropriate waveform shapes, it is necessary to perform an operation (calibration) for actually measuring each sensor output and setting the gain and bias to appropriate values. In the present embodiment, since the magnetic sensor is mounted only for two of the three phases, there is an advantage that calibration regarding the magnetic sensor for one phase can be omitted. Further, if the outputs SSA and SSB of the mounted two-phase magnetic sensor are correctly calibrated, there is an advantage that the phases of the three-phase drive signals can be easily matched. Furthermore, from the viewpoint of cost, the smaller the number of sensors, the better.

  FIG. 9 is a block diagram illustrating an internal configuration of the C-phase sensor signal generation unit 230. The C-phase sensor signal generation unit 230 includes five latch circuits 231 to 235 and an arithmetic circuit 236. The first and second latch circuits 231 and 232 latch the A-phase sensor output SSA and the B-phase sensor output SSB, respectively, in synchronization with the rising edge of the clock signal CLK. The third and fourth latch circuits 233 and 234 latch the outputs of the first and second latch circuits 231 and 232, respectively, in synchronization with the falling edge of the clock signal CLK. The arithmetic circuit 236 generates a C-phase sensor output SSC by executing an arithmetic operation using both the outputs of the first and second latch circuits 231 and 232 in real time. The fifth latch circuit 235 latches the sensor output SSC output from the arithmetic circuit 236 in synchronization with the falling edge of the clock signal CLK. As a result, three-phase sensor outputs SSA, SSB, and SSC are output from the three latch circuits 223 to 235 at the same timing.

FIG. 9B shows the contents of the calculation executed by the calculation circuit 236. In this table, the values of the sensor outputs SSA, SSB, SSC of each phase corresponding to the angle θ (phase) are shown. In this embodiment, it is assumed that the range of each sensor output is between 0 and VDD (VDD is a power supply voltage). At this time, the C-phase sensor output SSC can be calculated according to the following calculation formula.
SSC =-(SSB-(VDD / 2))-(SSA-(VDD / 2)) + (VDD / 2)
=-SSB-SSA + 3/2 ・ (VDD)

  Instead of the arithmetic circuit 236, it is also possible to use a look-up table having the A-phase and B-phase sensor outputs SSA and SSB as input values and the C-phase sensor output SSC as output values. This look-up table stores the above-described calculation results in advance, and is the same as the calculation circuit 236 in that the C-phase sensor output SSC is obtained based on the calculation. Note that the circuit for performing the above calculation can be realized by either an analog circuit or a digital circuit.

  FIG. 10A shows the internal configuration of the driver circuit. The driver circuits 250A to 250C for each phase constitute an H-type bridge circuit. For example, the A-phase driver circuit 250A drives the A-phase coil 11 according to the drive signals DRVA1 and DRVA2. Arrows denoted by reference signs IA1 and IA2 indicate directions of currents flowing through the drive signals DRVA1 and DRVA2, respectively. The same applies to the other phases. FIG. 10B shows an example of a driver circuit 250 in which three-phase coil groups 11 to 13 are star-connected to reduce the number of transistors.

  FIG. 11 is an explanatory diagram showing the internal configuration and operation of the drive signal generator 240 (FIG. 8A). For convenience of illustration, only the circuit elements for the A phase are shown here, but the same circuit elements are provided for the B phase and the C phase.

  The drive signal generation unit 240 includes a basic clock generation circuit 510, a 1 / N frequency divider 520, a PWM unit 530, a forward / reverse direction value register 540, a multiplier 550, an encoding unit 560, and a voltage command. A value register 580 and an excitation interval setting unit 590 are provided.

  The basic clock generation circuit 510 is a circuit that generates a clock signal PCL having a predetermined frequency, and is composed of, for example, a PLL circuit. The frequency divider 520 generates a clock signal SDC having a frequency 1 / N of the clock signal PCL. The value of N is set to a predetermined constant value. The value of N is set in the frequency divider 520 by the CPU 400 in advance. The PWM unit 530 is supplied from the clock signals PCL and SDC, the multiplication value Ma supplied from the multiplier 550, the forward / reverse direction indication value RI supplied from the forward / reverse direction indication value register 540, and the encoding unit 560. In response to the positive / negative sign signal Pa and the excitation interval signal Ea supplied from the excitation interval setting unit 590, the A-phase drive signals DRVA1 and DRVA2 (FIG. 5C) are generated. This operation will be described later.

  In the forward / reverse direction value register 540, a value RI indicating the rotation direction of the motor is set by the CPU 400. In the present embodiment, the motor rotates forward when the forward / reverse direction instruction value RI is at L level, and reverses when it is at H level. Other signals Ma, Pa, and Ea supplied to the PWM unit 530 are determined as follows.

  The output SSA of the magnetic sensor 40A is supplied to the encoding unit 560. The encoding unit 560 converts the range of the sensor output SSA and sets the value of the middle point of the sensor output to 0. As a result, the sensor output value Xa generated by the encoding unit 560 takes a value in a predetermined range on the positive side (for example, +127 to 0) and a predetermined range on the negative side (for example, 0 to −128). However, what is supplied from the encoding unit 560 to the multiplier 550 is the absolute value of the sensor output value Xa, and the sign of the sensor output value Xa is supplied to the PWM unit 530 as the sign signal Pa.

  Voltage command value register 580 stores voltage command value Ya set by CPU 400. This voltage command value Ya functions as a value for setting the applied voltage of the motor together with an excitation interval signal Ea described later, and takes a value of 0 to 1.0, for example. If the excitation interval signal Ea is set so that the entire excitation interval is set without providing the non-excitation interval, Ya = 0 means that the applied voltage is zero, and Ya = 1.0 is This means that the applied voltage is the maximum value. Multiplier 550 multiplies sensor output value Xa output from encoding unit 560 and voltage command value Ya to produce an integer, and supplies the multiplied value Ma to PWM unit 530.

  11B to 11E show the operation of the PWM unit 530 when the multiplication value Ma takes various values. Here, it is assumed that the entire period is an excitation interval and there is no non-excitation interval. The PWM unit 530 is a circuit that generates one pulse with a duty of Ma / N during one cycle of the clock signal SDC. That is, as shown in FIGS. 11B to 11E, the duty of the pulses of the A-phase drive signals DRVA1 and DRVA2 increases as the multiplication value Ma increases. The first drive signal DRVA1 is a signal that generates a pulse only when the sensor output SSA is positive, and the second drive signal DRVA2 is a signal that generates a pulse only when the sensor output SSA is positive. However, these are described together in FIGS. 11 (B) to 11 (E). For convenience, the second drive signal DRVA2 is drawn as a negative pulse.

  12 (A) to 12 (C) are explanatory diagrams showing the correspondence between the waveform of the sensor output and the waveform of the drive signal generated by the PWM unit 530. FIG. In the figure, “Hiz” means a high impedance state in which the electromagnetic coil is in an unexcited state. As described in FIG. 11, the A-phase drive signals DRVA1 and DRVA2 are generated by PWM control using an analog waveform of the sensor output SSA. Therefore, it is possible to supply an effective voltage indicating a level change corresponding to the change of the sensor output SSA to each coil using these A-phase drive signals DRVA1 and DRVA2.

  Further, the PWM unit 530 outputs a drive signal only in the excitation interval indicated by the excitation interval signal Ea supplied from the excitation interval setting unit 590, and does not output a drive signal in intervals other than the excitation interval (non-excitation interval). It is configured. FIG. 12C shows a drive signal waveform when the excitation interval EP and the non-excitation interval NEP are set by the excitation interval signal Ea. In the excitation interval EP, the drive signal pulse shown in FIG. 12B is generated as it is, and no drive signal pulse is generated in the non-excitation interval NEP. Thus, if the excitation interval EP and the non-excitation interval NEP are set, no voltage is applied to the coil in the vicinity of the middle point of the sensor output (this corresponds to the vicinity of the middle point of the back electromotive force waveform). Therefore, it is possible to further improve the efficiency of the motor. The excitation interval EP is preferably set to a symmetrical interval centered on the peak of the sensor output waveform (which is substantially equal to the back electromotive force waveform), and the non-excitation interval NEP is the middle of the sensor output waveform. It is preferable to set a symmetrical section centered on a point (center point).

  As described above, when the voltage command value Ya is set to a value less than 1, the multiplication value Ma becomes smaller in proportion to the voltage command value Ya. Therefore, the effective applied voltage can be adjusted also by the voltage command value Ya.

  As can be understood from the above description, in the motor of this embodiment, it is possible to adjust the applied voltage using both the voltage command value Ya and the excitation interval signal Ea. The relationship between the desired applied voltage, the voltage command value Ya, and the excitation interval signal Ea is preferably stored in advance as a table in a memory in the drive control circuit 200 (FIG. 8A). In this way, when the drive control circuit 200 receives a target value of a desired applied voltage from the outside, the CPU 400 outputs the voltage command value Ya and the excitation interval signal Ea according to the target value. Can be set. Note that it is not necessary to use both the voltage command value Ya and the excitation interval signal Ea to adjust the applied voltage, and only one of them may be used.

  FIG. 13 is a block diagram illustrating an example of an internal configuration of the PWM unit 530 (FIG. 11). The PWM unit 530 includes a counter 531, an EXOR circuit 533, and a drive waveform forming unit 535. These operate as follows.

  FIG. 14 is a timing chart showing the operation of the PWM unit 530 during normal rotation of the motor. In this figure, two clock signals PCL and SDC, forward / reverse direction instruction value RI, excitation interval signal Ea, multiplication value Ma, positive / negative sign signal Pa, count value CM1 in counter 531 and counter 531 The output S1, the output S2 of the EXOR circuit 533, and the output signals DRVA1 and DRVA2 of the drive waveform forming unit 535 are shown. The counter 531 repeats the operation of down-counting the count value CM1 to 0 in synchronization with the clock signal PCL every period of the clock signal SDC. The initial value of the count value CM1 is set to the multiplication value Ma. In FIG. 14, a negative value is also drawn as the multiplication value Ma for convenience of illustration, but the counter 531 uses the absolute value | Ma |. The output S1 of the counter 531 is set to H level when the count value CM1 is not 0, and falls to L level when the count value CM1 becomes 0.

  The EXOR circuit 533 outputs a signal S2 indicating an exclusive OR of the positive / negative sign signal Pa and the forward / reverse direction instruction value RI. When the motor rotates normally, the forward / reverse direction instruction value RI is at the L level. Therefore, the output S2 of the EXOR circuit 533 is the same signal as the positive / negative sign signal Pa. The drive waveform forming unit 535 generates drive signals DRVA1 and DRVA2 from the output S1 of the counter 531 and the output S2 of the EXOR circuit 533. That is, out of the output S1 of the counter 531, the signal during the period when the output S2 of the EXOR circuit 533 is at the L level is output as the first drive signal DRVA1, and the signal during the period when the output S2 is at the H level is output as the second drive signal DRVA2. Output as. In the vicinity of the right end of FIG. 14, the excitation interval signal Ea falls to the L level, thereby setting the non-excitation interval NEP. Accordingly, in this non-excitation interval NEP, none of the drive signals DRVA1, DRVA2 is output and the high impedance state is maintained.

  FIG. 15 is a timing chart showing the operation of the PWM unit 530 during motor reverse rotation. During reverse rotation of the motor, the forward / reverse direction instruction value RI is set to H level. As a result, it can be understood that the two drive signals DRVA1 and DRVA2 are interchanged from FIG. 14, and as a result, the motor reverses.

  FIG. 16 is an explanatory diagram showing the internal configuration and operation of the excitation interval setting unit 590. The excitation interval setting unit 590 includes an electronic variable resistor 592, voltage comparators 594, 596, and an OR circuit 598. The resistance value Rv of the electronic variable resistor 592 is set by the CPU 400. Voltages V1 and V2 across the electronic variable resistor 592 are applied to one input terminal of a voltage comparator 594,596. A sensor output SSA is supplied to the other input terminal of the voltage comparators 594 and 596. Output signals Sp and Sn of the voltage comparators 594 and 596 are input to the OR circuit 598. The output of the OR circuit 598 is an excitation interval signal Ea for distinguishing between excitation intervals and non-excitation intervals.

  FIG. 16B shows the operation of the excitation interval setting unit 590. Both-end voltages V1 and V2 of the electronic variable resistor 592 are changed by adjusting the resistance value Rv. Specifically, both-end voltages V1 and V2 are set to values having the same difference from the median value (= VDD / 2) of the voltage range. When the sensor output SSA is higher than the first voltage V1, the output Sp of the first voltage comparator 594 becomes H level, while when the sensor output SSA is lower than the second voltage V2, the second voltage V2 is output. The output Sn of the voltage comparator 596 becomes H level. The excitation interval signal Ea is a signal obtained by taking the logical sum of these output signals Sp and Sn. Therefore, as shown in the lower part of FIG. 16B, the excitation interval signal Ea can be used as a signal indicating the excitation interval EP and the non-excitation interval NEP. The excitation interval EP and the non-excitation interval NEP are set by the CPU 400 adjusting the variable resistance value Rv.

  As described above, in the brushless motor of the first embodiment, the magnetic sensor is mounted only for two phases of the three-phase coil group and the magnetic sensor is omitted for the other one phase. The work load related to the operation can be reduced, and the phases of the three-phase drive signals can be easily matched. Furthermore, a low-cost and efficient motor can be provided.

D. Regenerative control circuit configuration:
FIG. 17A is a block diagram showing a configuration of a regeneration control circuit of the brushless motor of the present embodiment. The regeneration control circuit 300 includes a C-phase sensor signal generation unit 330, a regeneration control signal generation unit 340, three-phase rectifier circuits 350A to 350C, an AD conversion unit 360, and a power output unit 380. The two sensor outputs SSA and SSB are converted into digital multilevel signals by the AD conversion unit 360 and supplied to the C-phase sensor signal generation unit 330. C-phase sensor signal generation unit 330 generates C-phase sensor simulation signal SSC shown in FIG. The internal configuration of the C-phase sensor signal generation unit 330 is the same as that described with reference to FIG. Note that it is possible to provide only one C-phase sensor signal generation unit and share the two control circuits 200 and 300. In this case, only one AD converter 260, 360 may be provided.

  The regeneration control signal generation unit 340 generates three-phase regeneration control signals (RECAp, RECAn), (RECBp, RECBn), (RECCp, RECCn) based on the three-phase sensor outputs SSA, SSB, SSC. The rectifier circuits 350 </ b> A to 350 </ b> C regenerate power from the three-phase electromagnetic coil groups 11 to 13 in the motor main body 100 in accordance with these three-phase regeneration control signals. The regenerated electric power is supplied to the outside via the power output unit 380.

  FIG. 18A shows the internal configuration of the rectifier circuit. The rectifier circuits 350A to 350C of each phase are respectively configured as full-wave rectifier circuits in which a rectifier element (diode) is added to an H-type bridge circuit. For example, the A-phase rectifier circuit 350 </ b> A regenerates power from the A-phase coil 11 in response to the regeneration control signals RECap and RECAn. The power regenerated from the three-phase coils 11 to 13 is output to the outside from the power output unit 380 as regenerative power signals RECp and RECn. FIG. 18B shows an example of a rectifier circuit 350 in which three-phase coil groups 11 to 13 are star-connected to reduce the number of transistors and diodes.

  FIG. 19 is an explanatory diagram showing the internal configuration and operation of the regeneration control signal generation unit 340. The regeneration control signal generation unit 340 includes an electronic variable resistor 342 and voltage comparators 344 and 346. The regenerative control signal generator 340 has the same configuration as that obtained by omitting the OR circuit 598 from the configuration of the excitation interval setting unit 590 shown in FIG. The resistance value Rv of the electronic variable resistor 342 is set by the CPU 400. The voltages V1 and V2 across the electronic variable resistor 342 are applied to one input terminal of the voltage comparators 344 and 346. A sensor output SSA is supplied to the other input terminal of the voltage comparators 344 and 346. As a result, the output signals RECAp and RECAn of the voltage comparators 344 and 346 are supplied to the control terminals of the transistors of the rectifier circuit 350A shown in FIG. In FIG. 19, only the A-phase circuit is shown, but the same circuit is provided for the B-phase and the C-phase.

  FIG. 19B shows the operation of the regeneration control signal generation unit 340. Both-end voltages V1 and V2 of the electronic variable resistor 342 are changed by adjusting the resistance value Rv. Specifically, both-end voltages V1 and V2 are set to values having the same difference from the median value (= VDD / 2) of the voltage range. When the sensor output SSA is higher than the first voltage V1, the output RECAp of the first voltage comparator 344 becomes H level, while when the sensor output SSA is lower than the second voltage V2, the second voltage V2 is output. The output RECAn of the voltage comparator 346 becomes H level. The interval in which the regenerative control signals RECAp and RECAn are at the H level is adjusted by the CPU 400 adjusting the variable resistance value Rv.

  It should be noted that the section in which the regenerative control signals RECap and RECAn are at the H level is preferably set to a symmetric section centered on the peak of the sensor output waveform (which is substantially equal to the back electromotive force waveform). If it does in this way, it is possible to collect | recover electric power efficiently from a coil.

  FIG. 20 is an explanatory diagram illustrating an example of sensor output and regenerative power during regeneration. 20A shows the sensor output SSA of the A-phase sensor 40A and the sensor output SSB of the B-phase sensor 40B, and FIG. 20B shows the C synthesized from the two sensor outputs SSA and SSB. The phase sensor simulation signal SSC is shown.

  FIG. 20A shows values of both-end voltages V1 and V2 (FIG. 19B) set in the regeneration control signal generation unit 340. FIG. 20C shows regenerative power regenerated in accordance with the setting of the both-end voltages V1 and V2. A combination of these three-phase regenerative power signals is output as regenerative power signals RECp and RECn (FIG. 18).

  As described above, in the regeneration control circuit of the present embodiment, the output of the other one-phase magnetic sensor is generated from the output of the mounted two-phase magnetic sensor, and the regeneration is performed using these three-phase sensor outputs. Since the control signal is generated, the phases of the three-phase regenerative control signals can be easily matched. As a result, regeneration can be performed efficiently.

E. Other examples:
FIG. 21 is a cross-sectional view showing a configuration of a motor body of a brushless motor as another embodiment of the present invention. The stator portion 10 and the rotor portion 30 of the motor main body 100a are each formed in a substantially cylindrical shape, and the rotor portion 30 circulates around the outer periphery of the stator portion 10.

  As can be understood from this example, various shapes can be adopted as the mechanical shape of the brushless motor of the present invention. The present invention is not limited to a three-phase four-pole motor, and can be applied to a brushless motor having any number of phases and poles.

FIG. 22 shows a method of calculating a simulated sensor output in a four-phase brushless motor as still another embodiment of the present invention. Note that the mechanical structure of the four-phase brushless motor is omitted. In the four-phase brushless motor, the C-phase sensor output SSC and the D-phase sensor output SSD are calculated according to the following arithmetic expression.
SSC =-(SSA-(VDD / 2)) + (VDD / 2)
=-SSA + VDD
SSD =-(SSB-(VDD / 2)) + (VDD / 2)
=-SSB + VDD

  In general, the correlation between m magnetic sensor outputs for an m-phase (m is an integer of 3 or more) electromagnetic coil group is expressed by some function (such as a trigonometric function). Therefore, even if the magnetic sensor is mounted only on n (n is an integer less than or equal to 2 and less than m) of the m phases, the simulated sensor output of the (mn) phase where the magnetic sensor is not mounted. Can be obtained by calculation using the output of the n-phase magnetic sensor as a variable. The simulated sensor output of the (mn) phase is preferably generated using one or more of n sensor outputs, and more preferably generated using two or more. For example, in the case of a three-phase motor as in the first embodiment, the sensor output of the remaining phase is not uniquely determined by only one of the two-phase sensor outputs, and both of the two sensor outputs are used. It is possible for the first time to determine the sensor output of the remaining phase.

  Thus, the present invention provides n magnetic sensors corresponding to the n-phase (n is an integer of 2 or more and less than m) of the m-phase (m is an integer of 3 or more) electromagnetic coil groups. Can be applied to generate a regenerative control signal (or drive signal) for an m-phase coil group from the outputs of these n-phase magnetic sensors. In addition, the present invention provides (mn) sets of regenerative control signals (or drive signals) for the (mn) phase electromagnetic coil groups that are not mounted on the n magnetic sensors that are mounted. The present invention can be applied to one generated by using one or more of sensor outputs.

F. Variation:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

F1. Modification 1:
In the above embodiment, an analog magnetic sensor is used, but a digital magnetic sensor having a multi-valued analog output may be used instead of the analog magnetic sensor. An analog magnetic sensor and a digital magnetic sensor having a multi-value output are common in that they have an output signal indicating an analog change. In this specification, “an output signal indicating an analog change” includes both a digital output signal having multiple levels of three or more values and an analog output signal, not an on / off binary output. Used in a broad sense.

F2. Modification 2:
As the PWM circuit, various circuit configurations other than the circuit shown in FIG. 11 can be adopted. For example, a circuit that performs PWM control by comparing the sensor output with a reference triangular wave may be used. Further, the drive signal may be generated by a method other than PWM control. A circuit that generates a drive signal by a method other than PWM control may be employed. For example, it is possible to employ a circuit that amplifies the sensor output and generates an analog drive signal.

F3. Modification 3:
In the above embodiment, a simulated sensor output relating to a phase in which the magnetic sensor is not mounted is generated, and the regeneration control signal (or drive signal) for that phase is generated using this, but the magnetic sensor is generated by other methods. A regenerative control signal (or drive signal) of a phase in which is not mounted may be generated. For example, an n-phase regeneration control signal (or drive signal) on which a magnetic sensor is mounted is generated, and the magnetic sensor is not mounted (m) using these n-phase regeneration control signals (or drive signals). -N) A phase regeneration control signal (or drive signal) may be generated.

F4. Modification 4:
The system of the present invention can be used as an electric vehicle and a hydroelectric generator (upstream: drive / downstream: power generation) by performing driving and power generation (regeneration) with a single electric motor.

It is explanatory drawing which shows the structure of the defrost fan as one Example of this invention, and a defrost fan system. It is a flowchart which shows the control action of a defrost fan system. It is sectional drawing which shows the structure of the motor main body of the brushless motor in an Example. It is explanatory drawing which shows the positional relationship of the magnet row | line | column and coil row | line | column at the time of operation | movement of a motor. It is explanatory drawing which shows the example of the sensor output at the time of forward rotation of a motor, and a drive signal. It is explanatory drawing which shows the example of the sensor output at the time of reverse rotation of a motor, and a drive signal. It is a block diagram which shows the structure of the motor control circuit of the brushless motor of a present Example. It is a block diagram which shows the structure of the drive control circuit of the brushless motor of a present Example. 4 is a block diagram showing an internal configuration of a C-phase sensor signal generation unit 230. FIG. It is a figure which shows the internal structure of a driver circuit. It is explanatory drawing which shows the internal structure and operation | movement of a drive signal production | generation part. It is explanatory drawing which shows the correspondence of a sensor output waveform and a drive signal waveform. It is a block diagram which shows the internal structure of a PWM part. It is a timing chart which shows operation | movement of the PWM part at the time of motor forward rotation. It is a timing chart which shows operation | movement of the PWM part at the time of motor reverse rotation. It is explanatory drawing which shows the internal structure and operation | movement of an excitation area setting part. It is a block diagram which shows the structure of the regeneration control circuit of the brushless motor of a present Example. It is a figure which shows the internal structure of a rectifier circuit. It is explanatory drawing which shows the internal structure and operation | movement of the regeneration control signal generation part 340. It is explanatory drawing which shows the example of the sensor output at the time of regeneration, and regenerative electric power. It is sectional drawing which shows the other structure of a motor main body. It is explanatory drawing which shows the calculation method of the simulated sensor output in the 4-phase brushless motor as another Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Stator part 11-13 ... Electromagnetic coil 30 ... Rotor part 32 ... Magnet 40A, 40B ... Magnetic sensor 42 ... Hall element 44 ... Bias adjustment part 46 ... Gain adjustment part 100 ... Motor main body 112 ... Rotating shaft 120 ... Circuit board 200 ... Drive control circuit 221 to 235 ... Latch circuit 230 ... C phase sensor signal generation unit 236 ... Calculation circuit 240 ... Drive signal generation unit 250 ... Driver circuit 260 ... AD conversion unit 330 ... C phase sensor signal generation unit 340 ... Regeneration control signal Generator 342 ... Electronic variable resistor 344, 346 ... Voltage comparator 350 ... Rectifier circuit 360 ... AD converter 380 ... Power output part 400 ... CPU
DESCRIPTION OF SYMBOLS 510 ... Basic clock generation circuit 520 ... Frequency divider 530 ... PWM part 531 ... Counter 533 ... EXOR circuit 535 ... Drive waveform formation part 540 ... Forward / reverse direction instruction value register 550 ... Multiplier 560 ... Encoding part 580 ... Command value register 590 ... excitation section setting unit 592 ... electronic variable resistor 594,596 ... voltage comparator 598 ... OR circuit 1000 ... motor control circuit 2000 ... frost-proof fan 2100 ... brushless motor 2200 ... fan blade 3000 ... control management device

Claims (8)

A defrost fan system,
A plurality of anti-frost fans,
A control management device for managing the operation of the plurality of defrost fans;
With
The control management device is a defrost fan system having a plurality of modes including a defrost mode in which the defrost fan is used for defrosting and a power generation mode in which the defrost fan is used as a generator. A frost-proof fan system according to claim 1,
Each anti-frost fan has a brushless motor,
The brushless motor is
a coil array having an m-phase (m is an integer of 3 or more) electromagnetic coil group;
A magnet array having a plurality of permanent magnets;
Among the m-phase electromagnetic coil groups, n magnetic sensors associated with an n-phase (n is an integer less than or equal to 2 and less than m) electromagnetic coil group, the relative positions of the magnet row and the coil row N magnetic sensors for detecting
A drive control circuit for controlling power supply to the coil array by using sensor outputs of the n magnetic sensors;
A regeneration control circuit for controlling regeneration of electric power from the coil array, using sensor outputs of the n magnetic sensors;
With
The drive control circuit includes:
Generating n sets of drive signals for the n-phase electromagnetic coil groups associated with the n magnetic sensors using the sensor outputs of the n magnetic sensors;
One of the sensor outputs of the n magnetic sensors is set to (mn) sets of drive signals for an (mn) phase electromagnetic coil group not associated with the n magnetic sensors. Generate using each of the above,
The regeneration control circuit is
Generating n sets of regenerative control signals for the n-phase electromagnetic coil groups associated with the n magnetic sensors using the sensor outputs of the n magnetic sensors;
(Mn) sets of regenerative control signals for the (mn) phase electromagnetic coil groups not associated with the n magnetic sensors are represented by one of the sensor outputs of the n magnetic sensors. A defrost fan system that uses two or more of each. The anti-frost fan system according to claim 2, further comprising:
The ((n−n) simulated sensor outputs for the (mn) phase electromagnetic coil group not associated with the n magnetic sensors are represented by the sensor outputs of the n magnetic sensors. A simulated sensor output generation unit that generates based on a calculation using one or more of them as a variable,
The drive control circuit is configured for the m-phase electromagnetic coil group according to m sensor outputs including sensor outputs of the n magnetic sensors and (mn) simulated sensor outputs. Generate m sets of drive signals,
The regenerative control circuit is configured for the m-phase electromagnetic coil group according to m sensor outputs including sensor outputs of the n magnetic sensors and (mn) simulated sensor outputs. A defrost fan system that generates m sets of regenerative control signals. A frost-proof fan system according to claim 3,
The simulated sensor output generator is
Among the sensor outputs of the n magnetic sensors, (mn) simulated sensor outputs for the (mn) phase electromagnetic coil group not associated with the n magnetic sensors A frost-proof fan system that is generated based on a calculation using two or more of the above as variables. A frost-proof fan system according to claim 3 or 4,
The simulated sensor output generation unit generates the simulated sensor output by real-time calculation using sensor outputs of the n magnetic sensors. A frost-proof fan system according to claim 3 or 4,
The simulated sensor output generation unit generates the simulated sensor output using a look-up table using sensor outputs of the n magnetic sensors as input values and the simulated sensor outputs as output values. Fan system. A frost-proof fan system according to any one of claims 2 to 6,
The frost-proof fan system, wherein the integer m is 3 and the integer n is 2. The frost-proof fan system according to claim 2,
The magnetic sensor is a frost-proof fan system that outputs an output signal indicating an analog change according to a relative position between the magnet row and the coil row.

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