JP4633521B2 - Brushless motor control device, control method, and motor system - Google Patents

Description

  The present invention relates to a control device and a control method for a brushless motor, and a motor system including such a control device and a brushless motor.

  The brushless motor control device performs energization control while switching energization to the stator winding wound in a coil shape, and the timing of switching energization is determined by detecting the magnetic pole position of the rotor. ing. In the conventional brushless motor control device, from the viewpoint of downsizing the entire system, the induced voltage generated in the stator winding by the rotation of the rotor is acquired without providing a position detection sensor separately, and the rotor rotation It is known to detect the position.

Here, when the energization is switched and the current is turned off, a flywheel current flows until the energy stored in the coil becomes zero, and a spike-like induced voltage (spike voltage) resulting from this flows in the stator. Occurs in the winding. For this reason, the control device needs to determine the switching timing after generating a mask signal and removing such spike voltage as noise. As a conventional method for removing the spike voltage, a voltage drop between the control device and the stator winding of the brushless motor is separately detected, and a reset signal is output when the voltage drop reaches the same potential as the reference voltage. It can be generated and position detection is ignored only during the spike voltage interval (see, for example, Patent Document 1).
JP-A-8-182379

However, in order to separately detect the voltage drop, a bidirectional diode, a bidirectional photocoupler, a flip-flop circuit, and the like are required, which causes a problem that the device configuration becomes complicated. In addition, when the reset signal is generated for a certain time from the generation of the spike voltage, the spike voltage may not be completely masked if the pulse width of the spike voltage changes due to load fluctuation. In such a case, the intersection between the induced voltage and the reference voltage cannot be detected, and the brushless motor may step out.
The present invention has been made in view of such circumstances, and an object of the present invention is to stably perform energization control without providing a separate sensor in a brushless motor.

The invention according to claim 1 of the present invention for solving the above-mentioned problem is to obtain a rotating magnetic field by energizing a plurality of stator windings arranged to give a rotating magnetic field to a rotor having a permanent magnet, The energization of the stator windings is sequentially switched based on the position detection signal obtained by comparing the change in the induced voltage generated in the stator winding that is not energized with the reference voltage by the rotation of the rotor. In the brushless motor control apparatus configured as described above, the mask signal generating means for masking the spike voltage pulse generated in the stator winding immediately after switching the energization to the stator winding, and the stator winding Judgment whether or not the edge of the spike voltage is detected when an edge that is not removed by the mask signal generating means is detected in the induced voltage signal based on the change in the induced voltage of the line And a control device for a brushless motor, characterized in that it comprises a stage, a.
In this brushless motor control device, in a steady state, a mask signal is generated by a mask signal generation means and a spike detection voltage is masked to generate a position detection signal. When the signal cannot be completely masked, the edge of the signal that cannot be masked by the determination means is identified. When it is determined that the edge is a spike voltage edge, the signal is removed and the edge to be used as a position detection signal is detected. If it is determined that there is, the signal is not removed.

According to a second aspect of the present invention, in the brushless motor control device according to the first aspect, when an edge that is not removed by the mask signal generating means is detected in the specific stator winding, It is determined whether or not the edge of the spike voltage is based on the level of the induced voltage of the stator winding.
In this brushless motor control device, when the determination means determines the edge of a specific stator winding, it checks whether the edge is a rising edge or a falling edge, and further determines the other stator windings. The level of the induced voltage is examined, and it is determined whether or not the edge to be determined is the spike voltage edge according to the combination of these.

According to a third aspect of the present invention, in the brushless motor control device according to the first or second aspect, when the edge detected by the determination means is determined to be caused by a spike voltage, the brushless motor is controlled. It has a stop processing means for outputting a stop signal for stopping the motor.
In this brushless motor control device, when the spike voltage that is equal to or less than the pulse width of the mask signal in the steady state cannot be completely removed by the mask signal, the load on the brushless motor is greatly increased, and the spike voltage pulse is increased. Assuming that the width has increased, the brushless motor is stopped.

According to a fourth aspect of the present invention, in the brushless motor control device according to the first or second aspect of the present invention, the generation cycle of the edge of the induced voltage signal that is periodically generated is measured, and a predetermined electrical angle is exceeded. When an edge of the next induced voltage signal is not detected, stop processing means is provided for outputting a stop signal for stopping the brushless motor.
In this brushless motor control device, when the pulse width of the spike voltage exceeds the pulse width of the mask signal in a steady state, the falling edge or rising edge of the next induced voltage is not detected even if it exceeds a predetermined electrical angle. If not detected, it is considered that the load applied to the brushless motor has greatly increased, and the brushless motor is stopped.

According to a fifth aspect of the present invention, there is provided a motor system comprising the brushless motor control device according to any one of the first to fourth aspects and the brushless motor.
In this motor system, when the pulse width of the spike voltage is larger than the pulse width of the mask signal, the spike voltage is removed by extracting the edge of the spike voltage by the judging means, and a position detection signal is created to create a position detection signal. Rotation control is performed.

According to a sixth aspect of the present invention, a rotating magnetic field is obtained by energizing a plurality of stator windings arranged so as to give a rotating magnetic field to a rotor having a permanent magnet, and energized by the rotation of the rotor. In a brushless motor control method for sequentially switching energization to the stator winding based on a position detection signal obtained by comparing a change in induced voltage generated in the stator winding with a reference voltage. Masking spike voltage pulses generated in the stator winding immediately after switching the stator winding, and the position detection signal when an edge that cannot be removed by the mask signal generating means is detected. And a step of determining whether the edge is the edge of the spike voltage or the edge of the spike voltage.
In this brushless motor control method, in a steady state, a mask signal is generated by a mask signal generating means and a spike voltage is masked to generate a position detection signal. When the signal cannot be completely masked, the edge of the signal that cannot be masked by the determination means is identified. When it is determined that the edge is a spike voltage edge, the signal is removed and the edge to be used as a position detection signal is detected. If it is determined that there is, the signal is not removed.

According to the present invention, when the pulse width of the spike voltage fluctuates due to the fluctuation of the load applied to the brushless motor, even if a signal that cannot completely remove the spike voltage by mask processing is generated, the signal is due to the spike voltage. Since it is determined whether or not there is a spike voltage, even if the pulse width of the spike voltage is large, it can be reliably removed. Therefore, the rotation of the brushless motor can be reliably controlled.
Further, if the brushless motor is stopped without being overloaded when the pulse width of the spike voltage exceeds a certain width, the brushless motor can be operated in an appropriate load region.

The best mode for carrying out the invention will be described in detail with reference to the drawings.
FIG. 1 shows a schematic configuration of a motor system including a brushless motor. This motor system includes a brushless motor 1 and a drive device 2 for the brushless motor 1, and is configured such that energization control is performed from a power source 3 via the drive device 2.
As shown in FIG. 2, the brushless motor 1 includes a stator 5 and a rotor 6 as main components. Three stator windings U, V, and W are wound around the stator, and a coil formed by these stator windings U, V, and W is a so-called star connection. The rotor 6 includes a rotating shaft and a permanent magnet in which a plurality of magnetic poles (N pole and S pole) are arranged along the circumferential direction of the rotating shaft. The brushless motor 1 may be an inner rotor type or an outer rotor type.

  As shown in FIG. 1, each of the stator windings U, V, W of the brushless motor 1 is drawn from the brushless motor 1 and connected to the driving device 2. The drive device 2 includes a control device 10 that performs a predetermined process by inputting a drive signal, and an output of the control device 10 is connected to a three-phase inverter 12 via a pre-driver 11. The three-phase inverter 12 is connected to the power source 3 and is configured to energize the stator windings U, V, and W according to the output of the control device 10. The analog waveform of the induced voltage that appears in each of the stator windings U, V, and W when the brushless motor 1 is energized from the three-phase inverter 12 is stepped down by the voltage dividing circuit 13 and then the induced voltage I / F (interface). The signal is input to the circuit 14. The induced voltage I / F circuit 14 generates the neutral point potential of the star connection as a reference voltage (equivalent neutral point voltage) from the respective voltages (induced voltages) of the stator windings U, V, and W. In addition, the waveform of the induced voltage of each stator winding U, V, and W and the equivalent neutral point voltage are input to the respective comparators to generate a digital signal. The output of each comparator is connected to the control device 10.

  Here, the control device 10 creates a start processing unit 21 to which a drive signal is input, an edge separation processing unit 22 connected to the induced voltage I / F circuit 14, and a signal for detecting the rotational position of the rotor 6. A rotor position detection unit 23 (determination unit) that performs an overload, a stop processing unit 24 (stop processing unit) that performs processing at the time of overload, an energization switching timing generation processing unit 25, and a mask signal for removing spike voltages. The function can be divided into the mask signal generator 26 (mask signal generator). Signals are output from the edge separation processing unit 22 to the rotor position detection unit 23 and the stop processing unit 24, and signals are output from the rotor position detection unit 23 to the stop processing unit 24 and the energization switching timing generation processing unit 25. Is output. Furthermore, signals are output from the start processing unit 21 and the stop processing unit 24 to the energization switching timing generation processing unit 25. Then, a signal is fed back from the energization switching timing generation processing unit 25 to the edge separation processing unit 22 via the mask processing unit 26, and final switching timing information is output to the pre-driver 11. It has become so. Detailed functions of each part will be described later. In addition, such a control apparatus 10 is implement | achieved by the single chip microcomputer etc., for example.

Next, the operation of this embodiment will be described.
First, with reference mainly to FIG. 2, a relationship between an energization pattern for energizing the brushless motor 1 from the driving device 2 and induced states of the stator 5 and the rotor 6 of the brushless motor 1 will be described. FIG. 2 shows a case where 120 ° energization rectangular wave driving is performed by an inner rotor type brushless motor.

  As shown in FIG. 2, there are six energization patterns (# 1 to # 6) in combination of three stator windings U, V, and W. In the energization pattern # 1, the stator winding W is energized from the stator winding W, and the stator 5 and the rotor 6 are in an induced state as shown in the pattern [A] when switching to the energization pattern # 1. become. Here, pattern [B] shows a state in which when energization pattern # 1 is maintained, torque is generated in rotor 6 and the electrical angle is rotated 30 ° in the CCW direction from the position of pattern [A]. . At this time, physically, the center of the stator winding W (open phase) and the center of the S pole of the rotor 6 face each other. Electrically, the equivalent neutral point voltage and the induced voltage cross each other. Such a state is set as a timing for detecting the rotational position of the rotor 6. Further, the pattern [C] is a state in which the rotor 6 is rotated by an electrical angle of 30 ° from the pattern [B]. Since this pattern [C] indicates the moment when the energization pattern is switched to # 2, if the energization pattern is switched at a timing at which the rotor 6 is rotated by an electrical angle of 30 ° from the timing at which the rotation position of the rotor 6 is detected. The rotor 6 can be rotated by a rotating magnetic field formed by the stator windings U, V, and W. When such energization patterns # 1 to # 6 are sequentially switched, the rotor 6 rotates with respect to the stator 5 while the induced state sequentially shifts to the patterns [A] to [L]. The patterns [B], [D], [F], [H], [J], and [L] all indicate the timing for detecting the rotational position of the rotor 6, and the torque generated at this time is the maximum. Torque.

Next, processing at the start of the brushless motor 1 will be described.
In the brushless motor 1 that does not have a position detection sensor, the position of the rotor 6 at the time of starting cannot be specified. Therefore, the energization timing generation processing unit 25 is set so that the start processing unit 21 outputs a predetermined energization pattern for a predetermined time. Control (initial operation). As a result, the rotor 6 is locked at a position corresponding to the energization pattern, and the initial position of the rotor 6 is determined. For example, when the energization pattern # 5 is executed as the initial operation, the rotor 6 is locked at the position indicated by the pattern [M], thereby determining the initial position. As the duration at this time, a value set in advance according to the physique of the brushless motor 1 and the inertia load is used. Then, an energization pattern that skips one from the current energization pattern is performed (skip energization). In the above example, the energization pattern # 5 is normally followed by the energization pattern # 6, while the skip energization is performed with the energization pattern # 1. Since the energization pattern # 6 is already passed through the position of the pattern [J] where the maximum torque can be obtained at the lock position of the pattern [M], even if the pattern # 6 is executed as it is, the position information is obtained. This is because the induced voltage at the maximum torque cannot be obtained. Therefore, by executing the pattern # 1, the pattern [M] is shifted to the pattern [A], and the same torque as that when the pattern [L] is shifted to the pattern [A] is generated. In this way, when the induced voltage generated by rotating the rotor 6 reaches a certain level and the position information is obtained, the operation shifts to the normal operation and the feedback control is performed. On the other hand, if the induced voltage does not reach a certain level, position information cannot be obtained. Therefore, after conducting the initial operation with the energization pattern # 1, the skip energization is performed with the energization pattern # 3. Thereafter, the same processing is repeated until normal operation becomes possible. In addition, you may produce | generate the switching timing of the electricity supply at the time of a start by the synchronous operation by an analog system.

Next, energization control during normal operation will be described with reference to FIGS.
In FIG. 3, the horizontal axis represents the electrical angle, and the vertical axis represents the energization state from the upper side to each of the stator windings U, V, W, and the actual induced voltage waveform Uv of each of the stator windings U, V, W. , Vv, Wv (analog signals) and induced voltage signals Ud, Vd, Wd (digital signals) of the respective stator windings U, V, W are shown. The energization state of the uppermost stator windings U, V, W is such that the stator windings U, V, W added with “+” in the upper stage are on the high potential side, and “−” is in the lower stage. It shows that the added stator windings U, V, W are on the low potential side. That is, “W +” and “V−” between the electrical angles of 0 ° and 60 ° indicate that the stator winding W is energized to the stator winding V (equivalent to the energization pattern # 1 in FIG. 2). . Further, for example, in the induced voltage waveform Uv, a pulse that rises at an electrical angle of 0 ° and a pulse that falls at an electrical angle of 180 ° are spike voltages Ps, and these spike voltages Ps are signals to be removed in this embodiment. is there.

  FIG. 4 is a diagram schematically showing a mask signal generation process and a position detection signal generation process. In FIG. 4, the horizontal axis represents the electrical angle, and the vertical axis represents the induced voltage signals Ud, Vd, Wd (the same signals as in FIG. 3) of the stator windings U, V, W from the upper side, and the stator windings. Position detection signals Us, Vs, Ws of lines U, V, W, position detection signals Uss, Vss, Wss after phase shift of electrical angle of 30 °, mask signal Um for stator winding U, stator winding The mask signal Vm for the line V and the mask signal Wm for the stator winding W are shown in order.

  The induced voltage waveforms Uv, Vv, Wv of the stator windings U, V, W shown in FIG. 3 are input to the induced voltage I / F circuit 14 (see FIG. 1), and the equivalent neutral point is calculated from these voltage values. A voltage is obtained. When this equivalent neutral point voltage and the induced voltage waveform Uv are input to the comparator, an induced voltage signal Ud is obtained. Similarly, induced voltage signals Vd and Wd as digital signals are obtained from induced voltage waveforms Vv and Wv as analog signals. These induced voltage signals Ud, Vv, Wv are input to the edge separation processing unit 22 of the control device 10, and the energization switching timing is generated by the following processing.

  First, the edge separation processing unit 22 separates the edge of the spike voltage Ps and the edge of the induced voltage generated by the rotation of the rotor 6 from the pulse signals of the induced voltage signals Ud, Vv, Wv, and the rotor position detecting unit 23. Creates position detection signals Us, Vs, Ws composed of information on the induced voltage generated by the rotation of the rotor 6, and passes them to the energization switching timing generation processing unit 25. The energization switching timing generation processing unit 25 counts the intervals Te of the edges (induced voltage edges) of the position detection signals Us, Vs, Ws shown in FIG. Specifically, measurement by the counter is started using all edges of the position detection signals Us, Vs, and Ws as triggers, and the count value is cleared when any edge of the position detection signals Us, Vs, and Ws is detected next. At the same time, the next count is started. Here, when the brushless motor 1 is rotating, the induced voltage edge interval Te is generated every 60 ° of electrical angle, and therefore the rotor 6 (see FIG. 2) is calculated from the count value indicating the induced voltage generation interval. The rotational speed and acceleration are calculated, and the next timing of switching the current is estimated accordingly, and the phase of the position detection signals Us, Vs, Ws is shifted by that amount to generate the phase detection signals Uss, Vss, Wss. . The control device 10 controls the three-phase inverter 12 in accordance with the phase detection signals Uss, Vss, Wss, and switches the energization to the stator windings U, V, W to rotate the rotor 6 of the brushless motor 1. Let

  Here, the energization switching timing generation processing unit 25 outputs the position detection signals Us, Vs, and Ws to the mask signal generation unit 26 at the same time or immediately before outputting a signal for instructing the 3-phase inverter 12 to switch energization. . The mask signal generation unit 26 receives the position detection signals Us, Vs, and Ws and generates mask signals Um, Vm, and Wm. For example, in the example of FIG. 4, the mask signal Wm of the stator winding W is set to H (High) at a timing corresponding to a predetermined electrical angle from the generation timing of the induced voltage edge of the position detection signal Us of the stator winding U. Set to level. Similarly, the mask signal Um of the stator winding U is set to the H (High) level at a timing corresponding to a predetermined electrical angle from the generation timing of the induced voltage edge of the position detection signal Vs of the stator winding V. The mask signal Vm of the stator winding V is set to the H (High) level at a timing corresponding to a predetermined electrical angle from the generation timing of the induced voltage edge of the position detection signal Ws of the stator winding W. The signal levels of these mask signals Um, Vm, Wm are changed to L (Low) level after being maintained for a predetermined electrical angle. The mask signals Um, Vm, and Wm are input to the edge separation processing unit 22.

  Note that the electrical angle that determines the pulse width of the mask signals Um, Vm, and Wm is always calculated in advance from the measured value of Te. Specifically, it is larger than the pulse width of the spike voltage Ps when rotating with a normal load, and the intersection of the induced voltage waveforms Uv, Vv, Wv and the equivalent neutral point voltage is not masked by the pulse of the mask signal. A value of 0 ° <θ <30 ° is used.

  Thereafter, the spike voltage Ps pulse is removed from the induced voltage signals Ud, Vd, Wd inputted from the induced voltage I / F circuit 14 by the mask signals Um, Vm, Wm, and the position detection signals Us, Vs, Ws is created and energization control of the brushless motor 1 is performed.

  Here, the pulse width of the spike voltage Ps varies depending on the size of the load and the rotation speed. On the other hand, since the mask signals Um, Vm, and Wm have a constant pulse width, there are cases where the pulse of the spike voltage Ps can be completely masked by the mask signals Um, Vm, and Wm and when the mask signal cannot be completely masked. The processing of the edge separation processing unit 22 in these cases will be described in order below.

  First, when the pulse width of the spike voltage Ps is equal to or smaller than the mask width, both the start edge and the end edge of the spike voltage Ps can be masked as shown in FIG. In this case, the rotor position detector 23 creates position detection signals Us, Vs, Ws from the induced voltage signals Ud, Vd, Wd according to the induced voltage signal detection logic as shown in Table 1.

  In FIG. 5, the rising edge and falling edge of the spike voltage Ps starting from the electrical angle θ1 are ignored because the mask signal Um is at the H level. Since the rising edge at the electrical angle θ2 satisfies the condition for the induced voltage signal Ud of the rising edge in Table 1, it is regarded as the rising edge of the induced voltage of the stator winding U. Similarly, the falling edge and rising edge of the spike voltage Ps starting from the electrical angle θ3 are ignored because the mask signal Um is at the H level. Since the falling edge of the induced voltage signal Ud at the electrical angle θ4 satisfies the conditions for the induced voltage signal Ud of the falling edge in Table 1, it is regarded as the falling edge of the induced voltage of the stator winding U. Similarly, with respect to the other induced voltage signals Vd and Wd, the rising edge and the falling edge of the induced voltage are determined according to the induced voltage signal detection logic shown in Table 1, and the position detection signals Us, Vs, and Ws are created.

  On the other hand, as shown in FIG. 6, when the pulse width of the spike voltage Ps exceeds the mask width, the start edge of the spike voltage Ps can be masked, but the end edge of the spike voltage Ps cannot be masked. . In such a case, the rotor position detector 23 separates the induced voltage edge by referring to the spike voltage end edge determination logic as shown in Table 2 in addition to the induced voltage signal detection logic as shown in Table 1. Then, the position detection signals Us, Vs, Ws are created.

  In FIG. 6, the rising edge of the spike voltage Ps starting from the electrical angle θ1 is masked, but the falling edge of the same spike voltage Ps cannot be masked, so the conditions of the falling edge shown in Tables 1 and 2 are satisfied. Check whether or not. In this case, since the condition for the induced voltage signal Ud of the falling edge in Table 2 is satisfied, it is regarded as the edge of the spike voltage Ps, and the position detection signal Us is created after removing this signal. The edge of the electrical angle θ2 satisfies the conditions in Table 1 as described above, and is therefore an induced voltage edge. Similarly, the falling edge of the spike voltage Ps starting from the electrical angle θ3 is removed by the mask signal Um, and the rising edge of the same spike voltage Ps is removed because it satisfies the condition for the induced voltage signal Ud of the rising edge in Table 2. To do. In this way, when there is a pulse of the spike voltage Ps that cannot be removed by the mask signal Um, the level of the voltage level of the other induced voltage signals Vd and Wd is examined and applied to the conditions in Tables 1 and 2. Thus, the necessity of removal is determined, and the signal based on the spike voltage Ps is removed to generate the position detection signal Us. Further, similarly, the position detection signals Vs and Ws are created.

Next, processing by the stop processing unit 24 of the control device 10 will be described.
As shown in FIG. 7, this process is a process for determining that the brushless motor 1 is in an overload state and stopping the brushless motor 1 when the load applied to the brushless motor 1 gradually increases. Hereinafter, in this processing, when the load increases from a state where the pulse of the spike voltage Ps can be completely masked with the mask widths of the mask signals Um, Vm, Wm created by the mask signal generation unit 26 in a steady state (load determination D1). A case where the load increases from a state where the pulse of the spike voltage Ps cannot be masked in a steady state (load determination D2) will be described separately.

  First, when the load determination D1, that is, when the pulse width of the spike voltage Ps is equal to or less than the mask width in the steady state, the stop processing unit 24 performs determination using the mask width as a threshold for overload determination. Specifically, when there is a spike voltage Ps pulse that cannot be removed by the mask signals Um, Vm, and Wm, the edge separation processing unit 22 passes the signal to the stop processing unit 24. Since it is unclear whether such a pulse is due to the spike voltage Ps or the induced voltage, it is determined whether or not the conditions in Table 2 are satisfied. As a result, if the condition of Table 2 is satisfied and the edge of the spike voltage Ps is found, it is regarded as an overload state. Accordingly, the stop processing unit 24 outputs a signal for instructing the stop to the energization timing switching generation unit 26 to stop the brushless motor 1.

  On the other hand, when the load determination D2, that is, when the pulse width of the spike voltage Ps exceeds the mask width in the steady state, the stop processing unit 24 performs determination using the predetermined electrical angle R1 as the overload determination threshold. . Here, as the predetermined electrical angle R1, a value set in advance according to the physique of the brushless motor 1 and the inertia load is used, but may be set to 360 °, for example. As shown in FIG. 7, when the induced voltage edge that normally appears periodically cannot be detected by the rotor position detector 23, the counter 24 is reset every time the induced voltage edge is detected. Check the value of. As a result, if the counter value does not reset even when the value exceeds the value corresponding to the electrical angle R1, it is considered that an overload condition has occurred. Accordingly, the stop processing unit 24 outputs a signal for instructing the stop to the energization timing switching generation unit 26 to stop the brushless motor 1.

  According to this embodiment, since the induced voltage is detected to calculate the energization switching timing and the energization timing is fed back, the mask signals Um, Vm, Wm for masking the spike voltage Ps are created. Regardless of the presence or absence of the spike voltage Ps, the mask signals Um, Vm, and Wm can always be generated. Therefore, even when the spike voltage Ps is generated in the process of repeating energization switching, the position of the rotor 6 can be accurately detected, and an appropriate timing can be obtained regardless of the type of the brushless motor 1 and the load state. The energization can be switched with. In addition, since it is not necessary to provide a separate external digital mask circuit for mask processing, the circuit scale can be reduced.

In addition, since the rotor position detection unit 23 extracts and removes the spike voltage Ps pulse using the logic shown in Tables 1 and 2, it does not depend on the type of the brushless motor 1 or the load. Thus, the position of the rotor 6 can be reliably detected. In particular, the position of the rotor 6 can be reliably detected even when the pulse width of the spike voltage Ps is larger than the pulse width of the mask signals Um, Vm, and Wm.
Further, when the pulse width of the spike voltage exceeds the mask width by the stop processing unit 23, or when the induced voltage edge does not appear even when the electrical angle exceeds 30 °, the brushless motor 1 is stopped as an overload. As a result, the brushless motor 1 can be quickly stopped when the load becomes excessive.

The present invention is not limited to the above-described embodiment, and can be widely applied without departing from the spirit of the invention.
For example, an advance angle correction means may be added to the control device 10 in order to cope with the case where the pulse width of the spike voltage changes greatly during load fluctuation. The advance angle correction means subtracts the energization switching period from the pulse width of the spike voltage, and sets a value obtained by halving the subtraction result as an advance angle correction value. The energization timing generation processing unit 25 uses the position detection signals Us, Vs, and Ws advanced by the advance correction value as position detection signals Uss, Vss, and Wss, and controls energization switching based on the signals.

It is a system configuration figure including a control device of a brushless motor concerning an embodiment of the invention. It is a figure which shows the energization pattern of a brushless motor, and the induced state of a stator and a rotor. It is a figure explaining the signal processing of the induced voltage waveform of a stator winding, Comprising: It is a timing chart which shows the procedure which produces a digital signal from an analog signal. It is a figure explaining the signal processing of the induced voltage waveform of a stator winding, Comprising: It is a timing chart which shows the preparation procedure of a mask signal, and the preparation procedure of the position detection signal after a mask process. It is a timing chart explaining the determination process of an induced voltage edge, Comprising: It is a figure which shows the case where the pulse width of a spike voltage is below the pulse width of a mask signal. It is a timing chart explaining the determination process of an induced voltage edge, Comprising: It is a figure which shows the case where the pulse width of a spike voltage exceeds the pulse width of a mask signal. It is a timing chart explaining the determination process of an induced voltage edge, Comprising: It is a figure explaining the determination process at the time of an overload.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brushless motor 6 Rotor 10 Control apparatus 23 Rotor position detection part (determination means)
24 Stop processing unit (stop processing means)
26 Mask signal generator (mask signal generator)
U, V, W Stator winding Ud, Vd, Wd Induced voltage signal Um, Vm, Wm Mask signal Uss, Vss, Wss Position detection signal

Claims (6)

A plurality of stator windings arranged to give a rotating magnetic field to a rotor having a permanent magnet is energized to obtain a rotating magnetic field, and the rotation of the rotor causes the stator windings that are not energized to occur. In a brushless motor control device configured to sequentially switch energization to the stator winding based on a position detection signal obtained by comparing the induced voltage change with a reference voltage,
Mask signal generating means for masking a spike voltage pulse generated in the stator winding immediately after switching the energization to the stator winding;
A determination means for determining whether or not an edge of the spike voltage is detected when an edge that is not removed by the mask signal generation means is detected in the induced voltage signal based on a change in the induced voltage of the stator winding;
A control device for a brushless motor, comprising:   When an edge that is not removed by the mask signal generation means is detected in a specific stator winding, whether the determination means is an edge of a spike voltage due to the level of the induced voltage of another stator winding. The brushless motor control device according to claim 1, wherein:   The stop processing means for outputting a stop signal for stopping the brushless motor when it is determined that the edge detected by the determination means is caused by a spike voltage. The brushless motor control device according to 2.   Measures the generation cycle of the periodically generated induced voltage signal edge, and outputs a stop signal for stopping the brushless motor if the edge of the next induced voltage signal is not detected even after exceeding a predetermined electrical angle. The brushless motor control device according to claim 1, further comprising a stop processing unit.   A motor system comprising the brushless motor control device according to any one of claims 1 to 4, and the brushless motor. A plurality of stator windings arranged to give a rotating magnetic field to a rotor having a permanent magnet is energized to obtain a rotating magnetic field, and the rotation of the rotor causes the stator windings that are not energized to occur. In a brushless motor control method for sequentially switching energization to a stator winding based on a position detection signal obtained by comparing a change in induced voltage with a reference voltage,
Immediately after switching the energized stator winding, the spike voltage pulse generated in the stator winding is masked, and the induced voltage signal based on the change in the induced voltage of the stator winding is removed by the mask. A control method for a brushless motor, wherein when a non-performed edge is detected, it is determined whether or not the edge is a spike voltage edge, and a spike detection pulse is removed to generate a position detection signal.

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