JP5250982B2 - Motor control apparatus, motor control method, motor control program, and image forming apparatus - Google Patents

Motor control apparatus, motor control method, motor control program, and image forming apparatus Download PDF

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JP5250982B2
JP5250982B2 JP2007047646A JP2007047646A JP5250982B2 JP 5250982 B2 JP5250982 B2 JP 5250982B2 JP 2007047646 A JP2007047646 A JP 2007047646A JP 2007047646 A JP2007047646 A JP 2007047646A JP 5250982 B2 JP5250982 B2 JP 5250982B2
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value
motor
means
pwm signal
motor control
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JP2008109835A (en
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孝尚 小池
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株式会社リコー
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Description

  The present invention relates to a motor control device, a motor control method, a motor control program, and an image forming apparatus that limit a current flowing through a driver for driving a motor within an allowable value.

  Conventionally, in order to protect a driver that drives a motor, a method for detecting the temperature of the driver and a method for detecting a drive current so that an excessive current does not flow through the driver are known. For example, Patent Document 1 proposes a technique in which an inverter circuit is provided with an overcurrent protection circuit and a temperature protection circuit in order to protect switching elements constituting the inverter circuit of the motor control device.

  Further, in Patent Document 2, an overcurrent is detected by an overcurrent detection circuit and rotation is stopped so that an external microcomputer can determine whether or not the drive current flowing through the inverter circuit is an overcurrent. There has been proposed a technique for outputting an arm reset signal indicating this together with a rotation speed signal.

  As described above, the conventional technology for protecting the driver uses a comparator that compares the current value with a predetermined current limit value, and if the current limit value is exceeded, a circuit that determines that an overcurrent is present in the driver or Provided outside the driver.

JP 2005-80349 A JP 2004-229430 A

  However, in the conventional method, since it is necessary to provide a comparator in the motor control device, there is a problem in that power consumption occurs due to the current detection resistor of the comparator, leading to a reduction in efficiency. In addition, there is a problem that the current limit value for determining whether or not an overcurrent can be freely changed. Furthermore, the cost increase due to the addition of the comparator itself and the cost increase due to an increase in the number of pins of the control IC are problematic.

  The present invention has been made in view of the above, and makes it possible to limit the current of a driver that drives a motor while avoiding a decrease in efficiency by not using an element such as a comparator for detecting overcurrent. An object is to provide a motor control device, a motor control method, a motor control program, and an image forming apparatus.

To solve the above problems and achieve the object, the present invention corresponds to the control means and, Ru voltage values being determined by the PWM signal for controlling a PWM signal for determining the voltage value supplied to the motor current Drive means for driving the motor by energizing the windings of the motor, and the control means is a speed detection means for detecting the rotation speed of the motor, and the motor is not rotating. The predetermined current limit value is exceeded based on the rotational speed detected by the speed detecting means after the predetermined first time and the predetermined second time after the lapse of the first time. and output means for outputting a PWM signal corresponding to the energizable voltage without current, wherein the output means during said second time, du of the PWM signal to be output immediately after elapse the second time Than tea value and outputs a PWM signal of a large duty value, said first period of time, it outputs a PWM signal of a large duty value than PWM signal output by the second time, and said.

Further, the present invention, the control means comprises a control step of controlling a PWM signal for determining the voltage value supplied to the motor, the drive means, a current corresponding to the Ru voltage values being determined by the PWM signal of the motor A drive step for driving the motor by energizing the winding, and the control step is determined in advance from a speed detection step for detecting a rotation speed of the motor and a state in which the motor is not rotating. A current value that does not exceed a predetermined current limit value based on the rotational speed detected by the speed detection step after the first time and a predetermined second time have elapsed since the first time has elapsed. comprising an output step of outputting a PWM signal corresponding to the energizable voltage value, wherein the output step is between the second time, and outputs immediately passed the second time P Than the duty value of the M signal and outputs a PWM signal of a large duty value, said first period of time, it outputs a PWM signal of a large duty value than PWM signal output by the second time, characterized by This is a motor control method .

The present invention also provides a motor control program that causes a computer to execute the motor control method.

The present invention also relates to an image forming apparatus for forming a toner image on a transfer target, wherein the toner image formed by being rotatably held and transporting means for transporting the transfer target is formed. An image carrier to be carried; charging means for uniformly charging the surface of the image carrier; latent image forming means for forming a latent image on the surface of the image carrier uniformly charged by the charging means; A developing unit that visualizes the latent image formed by the image forming unit, a transfer unit that is rotatably held and transfers the toner image visualized by the developing unit to the transfer target, the conveying unit, an image bearing member, and a motor controller for controlling the driving of the motor for rotating at least one of us and the transfer unit, the motor control device controls a PWM signal for determining the voltage value supplied to the motor Control means and the PWM signal Driving means for driving the motor by energizing the winding of the motor with a current corresponding to the voltage value determined by the control means, and the control means includes speed detecting means for detecting the rotational speed of the motor. Based on the rotational speed detected by the speed detecting means after a predetermined first time and a predetermined second time from the lapse of the first time from the state where the motor is not rotating. Output means for outputting a PWM signal corresponding to a voltage value capable of energizing a current value that does not exceed a predetermined current limit value, the output means for the second time period during the second time period. A PWM signal having a duty value larger than the duty value of the PWM signal output immediately after the lapse of time is output, and a duty larger than the PWM signal output in the second time during the first time. Outputting a PWM signal having a value, and wherein.

  According to the present invention, it is possible to limit the current of a driver that drives a motor without using an element such as a comparator for detecting overcurrent.

  In addition, according to the present invention, it is possible to appropriately give a necessary torque when the motor starts up, and it is possible to quickly reach the target value of the motor rotation speed.

  In addition, according to the present invention, there is an effect that it is possible to suppress the amount of heat generated after a predetermined period has elapsed while realizing an increase in torque at the time of startup.

  In addition, according to the present invention, it is possible to control a motor that does not include an FG and to control a motor that avoids the use of an FG in which the output may not be stable.

  Moreover, according to this invention, there exists an effect that the overflow of the counter at the time of rotational speed measurement can be avoided.

  Exemplary embodiments of a motor control device, a motor control method, a motor control program, and an image forming apparatus according to the present invention are explained in detail below with reference to the accompanying drawings.

(First embodiment)
The motor control device according to the first embodiment calculates a current value flowing through the driver from the motor rotation speed, and controls a PWM (Pulse Width Modulation) drive signal so that the calculated current value does not exceed the current limit value. To do.

  In this embodiment, a so-called composite function including a copy function, a facsimile (FAX) function, a print function, a scanner function, and an input image (an original image read by the scanner function or an image input by the printer or the FAX function) is combined. An example applied to a motor control apparatus that controls a motor provided in an image forming apparatus such as a digital multi-function peripheral called MFP (Multi Function Peripheral) will be described.

  FIG. 1 is an explanatory diagram showing the configuration of the image forming apparatus according to the present embodiment. As shown in FIG. 1, the image forming apparatus 10 includes a photosensitive belt 11, a charging unit 12, a latent image forming unit 13, a developing unit 0, a transfer unit 14, a cleaning unit 15, and an intermediate transfer belt 16. A transport roller 17, a fixing unit 18, a paper discharge roller 19, and a paper discharge tray 20.

  The photoreceptor belt 11 carries a toner image formed to be held rotatably. An organic photosensitive layer is formed on the surface 11 a of the photoreceptor belt 11. Around the photosensitive belt 11, a charging unit 12, a developing unit 0, a photosensitive belt cleaning unit 15a of the cleaning unit 15, and the like, which will be described later, are arranged.

  The charging unit 12 applies a high voltage to the surface 11 a of the photosensitive belt 11 to apply a uniform potential.

  The latent image forming unit 13 forms a latent image on the surface 11 a of the photosensitive belt 11 uniformly charged by the charging unit 12. The latent image forming unit 13 includes a laser (not shown), a polygon mirror 13a, an f / θ lens 13b, and a reflection mirror 13c. For example, the latent image forming unit 13 activates a laser in accordance with an image signal converted into each color output from a computer (not shown).

  That is, a laser beam corresponding to each image signal of black (K), cyan (C), magenta (M), and yellow (Y) is emitted from a laser (not shown), and this laser beam is emitted from the polygon mirror 13a and f. / Θ lens 13b and reflection mirror 13c are incident on surface 11a of photoreceptor belt 11 for optical writing to form electrostatic latent images of the respective colors.

The developing unit 0 visualizes the latent image formed by the latent image forming unit 13. The developing unit 0 has four black toner cartridges 0a each containing toner of each color charged by applying a charge opposite to the potential applied by the charging unit 12 to the surface 11a of the photosensitive belt 11. K) toner cartridge 0a 1 , cyan (C) toner cartridge 0a 2 , magenta (M) toner cartridge 0a 3 , and yellow (Y) toner cartridge 0a 4 .

  The developing unit 0 includes a developing roller 1 that abuts on the photosensitive belt 11 or rotates at the time of image formation while supplying a small distance and supplies toner. The development roller 1 is brought into contact with the surface 11a of the photosensitive belt 11 or the shock of the shock when maintaining a small interval is alleviated, and the image formation of a high-quality toner image is reduced at a high speed by reducing shock jitter and the like. Done.

Black (K) toner cartridge 0a 1 , cyan (C) toner cartridge 0a 2 , magenta (M) toner cartridge 0a 3 , yellow (Y) toner cartridge 0a 4 are black (K) of developing roller 1. A developing roller 1a, a cyan (C) developing roller 1b, a magenta (M) developing roller 1c, and a yellow (Y) developing roller 1d are provided, and toner of each color is electrostatically latentized through the developing rollers 1a to 1d. A toner image is formed by electrostatically attracting the image to make it visible.

  The transfer unit 14 includes a primary transfer unit 14 a that primarily transfers the toner image developed by the developing unit 0 to the intermediate transfer belt 16, and a secondary transfer unit 14 b that performs secondary transfer onto the transfer sheet (P). And.

  The cleaning means 15 scrapes off residual toner adhering to the surface 11a of the photoreceptor belt 11 having a toner image transferred onto an intermediate transfer belt 16 to be described later by means of the photoreceptor belt cleaning unit 15a for image formation in the next process. It is to be prepared.

  The intermediate transfer belt 16 is used in contact with a part of the surface 11 a of the photoreceptor belt 11. The intermediate transfer belt 16 applies a charge opposite to the toner of each color by the primary transfer device 14a of the transfer unit 14, thereby performing an operation for transferring the toner image on the intermediate transfer belt 16 for each color. A four-color superimposed image in which colors are superimposed is formed.

  The conveyance roller 17 conveys the transfer target (P). In the secondary transfer device 14 b of the transfer unit 14, 4 4 formed on the intermediate transfer belt 16 is formed by applying a charge opposite to the toner to the transfer sheet of the transfer target (P) transported by the transport roller 17. Each toner of the color-duplicated image is transferred to the transfer sheet of the transfer target (P).

  The fixing unit 18 melts and fixes the toners of the respective colors carried on the transfer paper of the transfer target (P) by heating and pressing by the heating roller 18a and the pressure roller 18b.

  The paper discharge roller 19 conveys transfer paper, which is a transfer target (P), on which the toner image is melted and fixed by the fixing unit 18, to the paper discharge tray 20.

  The above-described paper discharge roller 19 is driven by the photosensitive belt 11, the transport roller 17, the fixing unit 18, and the developing unit 0 by the main motor 25 or the transport motor 26 in FIG. Further, although the above-described image forming apparatus 10 performs the secondary transfer of the toner image, the image forming apparatus may be configured to transfer the toner image to the transfer sheet without performing the secondary transfer.

  Next, a control system centering on the main controller 40 of the image forming apparatus 10 according to the present embodiment will be described with reference to FIG.

  The image forming apparatus 10 includes a main controller 40 that controls the entire apparatus. The main controller 40 includes image processing for performing display for an operator, an operation unit 30 for performing function setting input control from the operator, control for a scanner, control for writing a document image in an image memory, control for image formation from the image memory, and the like. A distributed control device such as a unit (IPU) 49, an ADF (Auto Document Feeder) 1, and a finisher is connected. The operation unit 30 is connected to a liquid crystal touch panel 31, a numeric keypad 32, a clear / stop key 33, a print key 34, a preheat key 35, and the like. Each distributed controller and the main controller 40 exchange machine status and operation commands as necessary. A main motor 25 and various clutches 21 to 24 necessary for paper conveyance are also connected.

  The main controller 40 includes a motor control controller (motor control device) that controls various motors provided in the image forming apparatus 10 such as the main motor 25 and the transport motor 26. Hereinafter, the motor control device of the present embodiment will be described in detail by taking as an example a motor control device that is provided in the main controller 40 of the image forming apparatus 10 and controls the driving of various motors of the image forming apparatus 10 as described above. .

  The motor to be controlled is not limited to the main motor 25, and any motor in the image forming apparatus 10 can be the control target. Further, applicable motor control devices are not limited to those used in the image forming apparatus 10 such as a digital multi-function peripheral, and can be applied to motor control devices used in any device.

  FIG. 3 is a block diagram showing the configuration of the motor control device 200 according to the first embodiment of the present invention. As shown in the figure, the main motor 25 is a three-phase motor, and outputs a winding 211U, 211V, 211W corresponding to each phase, a hall element 212, and a pulse signal having a frequency according to the rotation of the main motor 25. FG (Frequency Generator) 213 to be provided. In addition, the motor control device 200 includes a PID control circuit 140, a driver 130, and a current limiting PWM circuit 120.

  The PID control circuit 140 performs a calculation by PID control according to the output of the FG 213 and outputs a PWM instruction value for instructing a torque necessary for rotation control of the main motor 25.

  The driver 130 drives the main motor 25 by supplying current to the windings 211U, 211V, 211W, and a three-phase output switching circuit 131 that switches the output of each phase in accordance with the output of the Hall element 212; 6 FET (Field Effect Transistor).

  The current limit PWM circuit 120 determines the allowable current of the driver 130 based on the PWM instruction value, the pulse signal (FG signal) output from the FG 213, and a current limit value determined in advance so that no overcurrent flows to the driver 130. PWM output (PWM signal) for outputting a current limited to a value that does not exceed is output to the driver 130. Details of the current limiting PWM circuit 120 will be described later.

  Here, the overcurrent protection function for the driver of the conventional motor control device will be described. FIG. 4 is a block diagram showing a configuration of a conventional motor control device 300. As shown in the figure, the motor control device 300 includes a PID control circuit 340, a driver 330, and a PWM circuit 320.

  Similar to the PID control circuit 140, the PID control circuit 340 performs calculation by PID control in accordance with the output of the FG 213, and outputs a PWM instruction value for instructing torque necessary for motor rotation control.

  In addition to the three-phase output switching circuit 331 that switches the output of each phase according to the output of the Hall element 212, the driver 330 includes a comparator 332 that compares a current value that is energized in the driver 330 with a reference value. .

  The PWM circuit 320 outputs a PWM signal to the driver 330 in accordance with the PWM instruction value input from the PID control circuit 340. In the conventional motor control device 300, when the drive current in the driver 330 exceeds the reference value, the PWM signal from the PWM circuit 320 to the driver 330 is turned off by the signal from the comparator 332.

  FIG. 5 is an explanatory diagram illustrating a timing chart of the PWM signal output from the PWM circuit 320 of the conventional motor control device 300. The upper part of the figure represents the PWM instruction value (PWM output 1) input from the PID control circuit 340. When an overcurrent is detected by the comparator 332, the signal (comparator output) from the comparator 332 is turned on, and the PWM signal (PWM output 2) output from the PWM circuit 320 is turned off accordingly. In this way, the output is limited to avoid overcurrent. When the drive current falls below the reference value, the comparator output is turned off, and the PWM signal is output from the next cycle.

  FIG. 6 is an explanatory diagram illustrating an example of a current waveform of a drive current flowing through the driver 330 of the conventional motor control device 300. In the conventional motor control device 300, even if a PWM instruction value that should have a current waveform as shown on the right side of the figure is input by the above-described function, the left side of the figure (overcurrent detection waveform). As shown in the figure, the current waveform is cut by the current exceeding the reference value.

  On the other hand, the motor control apparatus 200 according to the present embodiment does not include an element for detecting an overcurrent such as a comparator in the driver 130 as shown in FIG. 3, and instead suppresses the overcurrent with the current limiting PWM circuit 120. The driver 130 is protected by outputting the PWM signal controlled to do so.

FIG. 7 is an explanatory diagram for explaining the principle used in the present embodiment. In general, the current flowing through the motor decreases as the rotational speed of the motor increases. This is because an induced voltage is generated in the motor as the motor rotates. When the induction coefficient is K E and the rotational speed of the motor is ω, the induced voltage is expressed by K E ω. Further, the current flowing through the motor can be calculated by the equation shown in the lower part of FIG. Since ω = 0 in the initial state where the motor is not rotating, the motor is driven by a PWM signal that has a voltage value (initial voltage value) that is the product of the electric resistance value R of the winding 211 and the current limit value. Is done.

  FIG. 8 is a graph showing the relationship between the rotation speed and the value of the current flowing in the driver 130. As shown in the figure, the current value decreases linearly with respect to the rotational speed. Actually, when the rotational speed increases, the efficiency decreases due to the loss of the iron core, and the rotational speed becomes constant at a certain level. Immediately after driving the motor, the rotational speed is low, so that the current value exceeds the current limit value as shown in FIG. Therefore, it is necessary to limit the PWM signal in order to prevent overcurrent.

  In the present embodiment, the rotational speed of the motor is detected by the FG signal from the FG 213, and the value of the current flowing in the driver 130 is calculated by the equation of FIG. Then, the PWM signal is controlled so that the calculated current value does not exceed a predetermined current limit value.

  FIG. 9 is an explanatory diagram showing the duty of a PWM signal that is restricted so as not to exceed the current limit value (PWM duty limit value). As shown in the figure, the limit is tightened when the number of rotations of the motor is small, and the limit is weakened as the number of rotations increases. Further, after the rotation speed reaches a certain constant speed, the PWM duty limit value is set to a certain fixed value.

  FIG. 10 is an explanatory diagram showing changes in the rotational speed, the PWM instruction value, and the PWM duty limit value over time after the motor starts driving. FIG. 11 is an explanatory diagram showing the relationship of the PWM output value that is actually output with respect to the PWM instruction value and the PWM duty limit value.

  As shown in FIGS. 10 and 11, the PID control circuit 140 for instructing torque outputs a large PWM instruction value because the difference from the target speed is large at the beginning of motor startup. On the other hand, since the PWM duty limit value at the start of the motor is smaller than the PWM instruction value, the current limit PWM circuit 120 controls the output of the PWM signal (PWM output value) so that the duty does not exceed the PWM duty limit value. As the rotational speed increases, the PWM instruction value gradually decreases, so when a certain speed is reached, the PWM output value that is actually output is the PWM specified by the PID control circuit 140 from the PWM duty limit value. Switch to the indicated value.

  Next, details of the current limiting PWM circuit 120 that controls the PWM output value in this way will be described. FIG. 12 is a block diagram showing a detailed configuration of the current limiting PWM circuit 120. As shown in the figure, the current limiting PWM circuit 120 includes a speed detection unit 121, an averaging unit 122, a current calculation unit 123, a comparison unit 124, and a PWM output unit 125.

  The speed detector 121 receives the FG signal from the FG 213 and detects the rotational speed of the main motor 25 from the cycle of the FG signal (FG cycle).

  The averaging unit 122 calculates an average value of the rotational speeds detected by the speed detection unit 121 within a predetermined time. Specifically, the averaging unit 122 calculates the average value of the rotational speeds detected within the time until the number of pulses of the PWM signal reaches a predetermined number.

  The current calculation unit 123 calculates the current value from the average value of the rotation speed calculated by the averaging unit 122 and the currently output PWM output value by the calculation formula of FIG.

  The comparison unit 124 compares the current value calculated by the current calculation unit 123 with a predetermined current limit value.

  The PWM output unit 125 outputs a PWM signal that lowers the voltage value from the voltage value at the time of calculating the current value when the calculated current value is larger than the current limit value according to the comparison result of the comparison unit 124. is there. Specifically, when the calculated current value exceeds the current limit value, the PWM output unit 125 outputs a PWM signal in which the duty is reduced by a fixed amount.

  Next, a current limiting process performed by the motor control device 200 according to the first embodiment configured as described above will be described. FIG. 13 is a flowchart showing the overall flow of the current limiting process in the first embodiment.

  First, the current limiting PWM circuit 120 counts up the number of pulses of the PWM signal (step S1301). Here, the PWM signal pulse number counter is PWMCNT, and 1 is added to PWMCNT.

  Next, the speed detector 121 detects the pulse signal (FG signal) from the FG 213, calculates the time between the pulse signals (step S1302), and counts up the number of detected pulse signals (step S1303). Here, the time between pulse signals is FGT, the number of detected pulse signals is Nfg, and 1 is added to Nfg.

  Next, the speed detection unit 121 adds the time between the detected pulse signals (step S1304). Here, the time between the detected pulse signals is added to FGVAL.

  Next, the current limiting PWM circuit 120 determines whether or not the number of PWM pulses (PWMCNT) exceeds a predetermined threshold value (n) (step S1305). If not (step S1305: NO), step S1301 Return to and repeat the process.

When the number of PWM pulses (PWMCNT) exceeds a predetermined threshold (n) (step S1305: YES), the averaging unit 122 calculates the average value of the rotational speed from the time (FGVAL) between the pulse signals detected during that time. Is calculated (step S1306). Specifically, the averaging unit 122 calculates the average value of the rotation speed by the following equation (1).
ω = 2πNfg / (FGVAL) (1)

Next, the current calculation unit 123 calculates the average value of the rotation speed, the duty (Duty) of the current PWM signal, the power supply voltage (V) of the driver 130, the resistance value (R) of the driver 130, and the induction coefficient K. A drive current value flowing through the driver 130 is calculated from E (step S1307). Specifically, the current calculation unit 123 calculates a current value by the following equation (2).
I = (V × Duty−K E ω) / R (2)

  Next, the comparison unit 124 determines whether or not the calculated current value is greater than a predetermined current limit value (step S1308). When the calculated current value is larger than the predetermined current limit value (step S1308: YES), the PWM output unit 125 outputs a PWM signal with the duty decreased by a certain amount (const) (step S1309). Note that the PWM signal may be turned off instead of decreasing the duty by a certain amount.

  Next, the current limiting PWM circuit 120 initializes PWMCNT, Nfg, and FGVAL to 0 (step S1310), returns to step S1301, and repeats the processing.

  As described above, in the present embodiment, the current value flowing through the driver 130 is calculated using the rotation speed of the main motor 25 calculated from the FG signal, and the PWM is performed so as not to exceed the current limit value in the current limit PWM circuit 120. The signal can be controlled. For this reason, protection from an overcurrent can be realized without providing a comparator in the driver 130.

  Next, a modification of the first embodiment will be described. In the above-described current limiting PWM circuit 120, the PWM signal is controlled by calculating the current value from the rotation speed. On the other hand, a method of outputting a PWM signal that avoids an overcurrent according to the rotation speed by referring to a conversion table in which the duty of the PWM signal according to the rotation speed is determined in advance can be considered.

  FIG. 14 is a block diagram showing another configuration of a current limiting PWM circuit 1420 for realizing such a method. As shown in the figure, the current limiting PWM circuit 1420 includes a speed-duty conversion table 151, a speed detecting unit 121, an averaging unit 122, and a PWM output unit 1425.

  The speed-duty conversion table 151 is a storage unit that stores the rotational speed of the main motor 25 in association with the duty value of the PWM signal that can energize a current value that does not exceed the current limit value.

  Since the functions of the speed detection unit 121 and the averaging unit 122 are the same as those of the speed detection unit 121 and the averaging unit 122 in the current limiting PWM circuit 120 described above, the description thereof is omitted.

  The PWM output unit 1425 acquires the duty value of the PWM signal corresponding to the average value of the rotation speed calculated by the averaging unit 122 from the speed-duty conversion table 151, and outputs the acquired duty value to the driver 130. .

  Next, a current limiting process performed by the motor control device 200 according to the modification of the first embodiment configured as described above will be described. FIG. 15 is a flowchart showing an overall flow of the current limiting process in the modification of the first embodiment.

  Since the rotation speed detection process and the averaging process from step S1501 to step S1506 are the same as those from step S1301 to step S1306, description thereof will be omitted.

  After calculating the average value of the rotation speed, the PWM output unit 1425 acquires the duty corresponding to the calculated average value of the rotation speed from the speed-duty conversion table 151 and outputs it to the driver 130 (step S1507). The parameter initialization process in step S1508 is the same process as in step S1310.

  As described above, by using the speed-duty conversion table 151 that is predetermined according to the current limit value, it is possible to control the PWM signal so as to prevent overcurrent according to the rotational speed of the motor. Further, since the current calculation unit 123 and the comparison unit 124 as described above are not necessary, the circuit configuration can be simplified.

  As described above, in the motor control device according to the first embodiment, the PWM signal can be controlled so that the current value supplied to the driver does not exceed the current limit value according to the rotational speed of the motor. . Therefore, it is possible to limit the current of the driver that drives the motor without using an element such as a comparator for detecting overcurrent.

(Second Embodiment)
In the first embodiment, the PWM signal is controlled so as to prevent overcurrent immediately after the motor is started. However, since the starting torque is required when the motor starts up, the required torque is often larger than usual. Further, if it is only the moment of rising, a large current can be passed if the heat generation of the driver does not exceed the allowable range even if the current exceeds a certain amount. Therefore, the motor control device according to the second embodiment controls the current value in a predetermined period immediately after startup to be high in order to obtain a necessary torque when the motor starts up.

  FIG. 16 is a block diagram showing a configuration of a current limiting PWM circuit 1620 of the motor control device according to the second embodiment. As shown in the figure, the current limiting PWM circuit 1620 of the second embodiment includes a speed detection unit 121, an averaging unit 122, a current calculation unit 123, a comparison unit 124, a PWM output unit 1625, A timer 1626 and a maximum duty determination circuit 1627 are provided.

  In the second embodiment, the timer 1626 and the maximum duty determination circuit 1627 are added, and the function of the PWM output unit 1625 is different from that of the current limiting PWM circuit 120 of the first embodiment. Other configurations and functions are the same as those in FIG. 12, which is a block diagram showing the configuration of the current limiting PWM circuit 120 according to the first embodiment.

  The timer 1626 measures time. The maximum duty determination circuit 1627 refers to the output value from the timer 1626, and outputs a predetermined initial value as the duty of the PWM signal from the start of motor startup (initial state) to a predetermined time (ts). To decide.

  The PWM output unit 1625 outputs the initial value determined by the maximum duty determination circuit 1627 as a PWM output value until ts, and after ts, the PWM output according to the rotation speed is performed in the same manner as in the first embodiment. A value is calculated and output.

  FIG. 17 is an explanatory diagram showing an example of the duty value of the PWM signal output in the second embodiment. As shown in the figure, the duty value is set to a predetermined initial value in order to increase the starting torque from the start of the motor start to ts. After the elapse of ts, a limited value (PWM duty limit value) is output in consideration of the rotational speed as in the first embodiment.

  Next, the duty determination process by the motor control device according to the second embodiment configured as described above will be described. FIG. 18 is a flowchart showing the overall flow of the duty determination process in the second embodiment.

  First, the maximum duty determination circuit 1627 refers to the output value from the timer 1626 and determines whether or not the time from the start of the motor is smaller than a predetermined threshold value (ts) (step S1801). If smaller than ts (step S1801: YES), the maximum duty determination circuit 1627 sets the duty to a predetermined initial value (step S1802). The PWM output unit 1625 outputs a PWM signal having a duty corresponding to the initial value to the driver 130.

  If the time from the start of the motor is greater than ts (step S1801: NO), a current limiting process for limiting the duty of the PWM signal to a value corresponding to the rotation speed is executed (step S1803). As the current limiting process, any one of the processes described in FIG. 13 or FIG. 15 of the first embodiment can be applied.

  As described above, in the motor control device according to the second embodiment, the current value in a predetermined period immediately after the start can be controlled to be high, so that the necessary torque can be appropriately given when the motor starts up. It is possible to quickly reach the target value.

(Third embodiment)
In the second embodiment, the duty value for a predetermined time after start-up is set large in order to minimize the delay of mechanical start-up of the motor. If the adjustment stage of the duty limit is increased, the starting torque can be further increased. The motor control apparatus according to the third embodiment controls the current value in a predetermined period immediately after startup higher in consideration of the current rise time (electrical time constant) immediately after startup.

  FIG. 19 is an explanatory diagram showing the relationship between the rise of current after the start of motor startup and the rise of motor rotation speed. As shown in the figure, when a voltage is applied to the motor, the electrical rise time te is generally much shorter than the mechanical rise time tm. In the present embodiment, the initial value of the duty value of the PWM signal is changed every predetermined time corresponding to each of te and tm.

  FIG. 20 is an explanatory diagram showing an example of the duty value of the PWM signal output in the third embodiment. As shown in the figure, from the start of the motor to t1 corresponding to the rise delay time due to the L component of the coil, the PWM signal is started with a 100% duty.

  When it rises electrically, the PWM duty limit value is added for the rising torque up until t2 time when it rises mechanically. After the mechanical start-up, the duty is controlled according to the normal WPM instruction value. Thereby, the torque increase at the time of starting is implement | achieved and the emitted-heat amount of the area from t2 to t3 can be reduced.

  FIG. 21 is a block diagram showing a configuration of a current limiting PWM circuit 2120 of the motor control device according to the third embodiment. As shown in the figure, the current limiting PWM circuit 2120 of the third embodiment includes a speed detection unit 121, an averaging unit 122, a current calculation unit 123, a comparison unit 124, a PWM output unit 2125, A timer 1626, a maximum duty determination circuit 2127, and a sequencer 2128 are provided.

  In the third embodiment, the sequencer 2128 is added, and the functions of the PWM output unit 2125 and the maximum duty determination circuit 2127 are different from those of the first embodiment. Other configurations and functions are the same as those in FIG. 16, which is a block diagram showing the configuration of the current limiting PWM circuit 1620 of the motor control device according to the second embodiment. Is omitted.

  The sequencer 2128 refers to the time elapsed from the start of the motor and controls the start mode representing the start state according to the time elapsed after the motor start. FIG. 22 is a state transition diagram showing the relationship between the activation modes. As shown in the figure, when starting is started from an initial state where the motor is not started (idle mode), the mode is changed to a full mode in which the duty is maximized. Thereafter, when t1 time elapses, the mode changes to an acceleration mode for increasing torque. When the time t2 further elapses, a transition is made to the normal mode in which normal duty control is performed.

  The maximum duty determination circuit 2127 refers to the output of the sequencer 2128 and determines the duty value of the PWM signal according to the start mode. Specifically, the duty value is determined to be 100% in the full mode, and the duty value is determined to be a predetermined initial value in the acceleration mode.

  The PWM output unit 2125 controls and outputs the PWM output value according to the duty value determined by the maximum duty determination circuit 2127. Specifically, the PWM output unit 2125 outputs a 100% duty value in the full mode after startup, outputs a predetermined initial value in the acceleration mode, and after transitioning to the normal mode, the PWM output unit 2125 is the same as in the first embodiment. By a similar method, a PWM output value corresponding to the rotation speed is calculated and output.

  Next, the duty determination process by the motor control device according to the third embodiment configured as described above will be described. FIG. 23 is a flowchart showing an overall flow of the duty determination process in the third embodiment.

  First, the sequencer 2128 refers to the output value from the timer 1626 and determines the motor start mode (step S2301). Next, the maximum duty determination circuit 2127 determines a duty value corresponding to the activation mode.

  Specifically, first, the maximum duty determination circuit 2127 determines whether or not the activation mode is the full mode (step S2302). If the activation mode is the full mode (step S2302: YES), the duty value is set to 100%. Setting is performed (step S2303). The PWM output unit 2125 outputs a PWM signal to the driver 130 with a 100% duty.

  When not in the full mode (step S2302: NO), the maximum duty determination circuit 2127 determines whether or not the activation mode is the acceleration mode (step S2304). When the acceleration mode is set (step S2304: YES), the maximum duty determination circuit 2127 sets the duty value to a predetermined initial value (step S2305). This initial value means a value determined with the intention of increasing torque, as in step S1802 of the second embodiment.

  When not in the acceleration mode (step S2304: NO), a current limiting process for limiting the duty of the PWM signal to a value corresponding to the rotation speed is executed (step S2306). As the current limiting process, any one of the processes described in FIG. 13 or FIG. 15 of the first embodiment can be applied.

  Thus, in the motor control device according to the third embodiment, the PWM duty for controlling the current value in a predetermined period immediately after start-up is maximized in consideration of the current rise time immediately after start-up. It is possible to suppress the amount of heat generated after a predetermined period while increasing the torque at the time of startup.

(Fourth embodiment)
In the first to third embodiments, a pulse signal from the FG is used as an input for speed detection. However, in the case of FG, there is a problem that the output is not stable until a constant rotational speed is reached. In addition, since there is a motor that does not use the FG itself, another means is required as a speed detection method. The motor control apparatus according to the fourth embodiment detects the rotation speed of the motor using a pulse signal from the Hall element instead of detecting the rotation speed by a signal from the FG.

  FIG. 24 is a block diagram illustrating a configuration of a motor control device 2400 according to the fourth embodiment. As shown in the figure, the motor control device 2400 includes a PID control circuit 140, a driver 130, and a current limiting PWM circuit 2420.

  In the fourth embodiment, the function of the current limiting PWM circuit 2420 is different from that of the first embodiment. Other configurations and functions are the same as those in FIG. 3, which is a block diagram showing the configuration of the motor control device 200 according to the first embodiment, and thus are denoted by the same reference numerals and description thereof is omitted here.

  The current limit PWM circuit 2420 is different from the current limit PWM circuit 120 of the first embodiment in that the current value is calculated by inputting the pulse signal output from the Hall element 212 instead of the FG signal. Although not shown in FIG. 24, since the main motor 25 of the present embodiment is a three-phase motor, three Hall elements 212 are provided for each phase. Hereinafter, the three Hall elements are referred to as Hall element A, Hall element B, and Hall element C.

  In the present embodiment, the current limiting PWM circuit 2420 increases the resolution by synthesizing the outputs from the three Hall elements A, B, and C. FIG. 25 is an explanatory diagram showing an example of the output from the synthesized Hall element. As shown in the figure, by calculating the exclusive OR of the signal waveforms from the three Hall elements A, B, and C, a combined waveform obtained by combining the signals can be obtained. The speed detector 121 of the current line source PWM circuit 2420 detects the rotational speed of the motor from the signal synthesized in this way. Since the control process of the PWM signal after detecting the rotation speed is the same as that of the first embodiment, the description thereof is omitted.

  As described above, in the motor control device according to the fourth embodiment, since the rotation speed of the motor can be detected using the pulse signal from the Hall element, the control and output of the motor not equipped with the FG can be performed. The motor can be controlled while avoiding the use of FG which may not be stable.

(Fifth embodiment)
In each of the above-described embodiments, the time between the input pulses of the FG or the Hall element is measured in order to detect the rotation speed. Since the rotation speed is proportional to the reciprocal of the time between the input pulses, the value of the measurement result becomes excessive at low speed (such as at the time of startup), and the counter may overflow. Further, at high speed, there is a problem that the count number between pulses becomes too small and the measurement resolution becomes small. The motor control device according to the fifth embodiment changes the count-up clock in accordance with the change in the length of time between pulses during rotation speed measurement.

  FIG. 26 is a block diagram illustrating a configuration of a motor control device 2800 according to the fifth embodiment. As shown in the figure, the motor control device 2800 includes a PID control circuit 140, a driver 130, a current limit PWM circuit 2820, and an adjustment circuit 2840.

  In the fifth embodiment, the adjustment circuit 2840 is added, and the function of the current limiting PWM circuit 2820 is different from that of the first embodiment. Other configurations and functions are the same as those in FIG. 1 which is a block diagram showing the configuration of the motor control device 200 according to the first embodiment, and thus the same reference numerals are given and description thereof is omitted here.

  The current limit PWM circuit 2820 inputs a time between pulse signals that are counted by adjusting the number of clocks by an adjustment circuit 2840 described later, and controls the PWM signal using the input time. FIG. 27 is a block diagram showing a detailed configuration of the current limiting PWM circuit 2820. As shown in the figure, the current limiting PWM circuit 2820 includes a speed detection unit 2821, an averaging unit 122, a current calculation unit 123, a comparison unit 124, and a PWM output unit 125.

  In the fifth embodiment, the function of the speed detector 2821 is different from that of the first embodiment. Other configurations and functions are the same as those in FIG. 12, which is a block diagram showing the configuration of the current limiting PWM circuit 120 according to the first embodiment.

  The speed detector 2821 receives time between pulse signals that are count values output from the adjustment circuit 2840, and detects the rotational speed of the main motor 25 from the input time.

  The adjustment circuit 2840 adjusts the clock of the counter that counts the time between the FG signals input from the FG 213, and outputs the time counted by the adjusted clock. FIG. 28 is a block diagram showing a detailed configuration of the adjustment circuit 2840. As shown in the figure, the adjustment circuit 2840 includes a frequency division sequencer 2841, a frequency division circuit 2842, a counter 2843, a comparison unit 2844 and a comparison unit 2845.

  The comparison unit 2844 compares the measured count value with a predetermined upper limit value (upper reference value), and sends a signal indicating that the count value has exceeded when the count value exceeds the upper reference value to the frequency dividing sequencer 2841. Output. The comparison unit 2845 compares the measured count value with a predetermined lower limit value (lower reference value), and when the count value falls below the lower reference value, a signal indicating that the count value has fallen is sent to the frequency dividing sequencer 2841. Output.

  The frequency division sequencer 2841 controls the frequency division ratio of the counter 2843 according to the outputs of the comparison unit 2844 and the comparison unit 2845.

  The frequency dividing circuit 2842 divides the system clock (system CLK) by the frequency dividing ratio set by the frequency dividing sequencer 2841. The counter 2843 counts the pulse signal from the FG 213 using the clock divided by the frequency dividing circuit 2842.

  Next, frequency division ratio setting processing performed by the motor control device 2800 according to the fifth embodiment configured as described above will be described. FIG. 29 is a flowchart showing an overall flow of the frequency division ratio setting process in the fifth embodiment.

  First, the frequency division sequencer 2841 sets an initial value of a predetermined frequency division ratio for the clock of the counter 2843 (step S3101). Thereafter, the frequency dividing circuit 2842 generates a clock with the set frequency dividing ratio, and the counter 2843 starts counting the time between the pulse signals from the FG 213 according to the generated clock.

  Next, the comparison unit 2844 determines whether or not the counter value is larger than the upper reference value (step S3102). If the counter value is larger (step S3102: YES), the frequency division sequencer 2841 decreases the clock frequency division ratio. (Step S3103). When the counter value is not larger than the upper reference value (step S3102: NO), the comparison unit 2845 determines whether or not the counter value is smaller than the lower reference value (step S3104).

  When the counter value is smaller than the lower reference value (step S3104: YES), the frequency division sequencer 2841 increases the clock frequency division ratio (step S3105). When the counter value is not smaller than the lower reference value (step S3104: NO), the current limiting process is executed without changing the clock cycle (step S3106).

  Next, a specific method for reducing the frequency division ratio or increasing the frequency division ratio at step S3103 or step S3105 will be described. In the following, the case where the rotational speed of the motor is slow and the case where the rotational speed of the motor is fast will be described separately.

  First, the case where the rotational speed of the motor becomes slow will be described. FIG. 30 is an explanatory diagram for explaining the pulse period and the count value. The horizontal axis of the graph is time (t), and the vertical axis is the pulse detection voltage. As shown in the figure, when the rotational speed of the motor is slowed down, the pulse period increases, and the count value when the interval between pulses (α) is counted with a clock having a constant period also increases. The figure shows an example in which the count value increases to 9 counts, 14 counts, and 20 counts as the rotational speed decreases.

  FIG. 31 is a diagram showing the count value between pulses (α) when the pulse period increases. The horizontal axis of the graph is time (t), and the vertical axis is the count value. If the count value between pulses becomes excessive, the counter 2843 may overflow. Therefore, the comparison unit 2844 determines whether or not the count value is larger than a predetermined upper reference value (γ). If the count value is larger, the frequency division sequencer 2841 determines the frequency division ratio and divides the clock. To do. The predetermined upper reference value (γ) is obtained by subtracting an arbitrary value from the maximum value of the counter 2843 so as not to overflow even if the next count value is larger than expected. Dividing is to convert the frequency to 1 / n. For example, dividing by 2 doubles the period, and when counting up the same length, it is possible to count with 1/2 count value. . This n is called a frequency division ratio.

  When the frequency dividing sequencer 2841 performs frequency division, if an excessive frequency dividing ratio is used, the resolution with respect to the pulse becomes too small. If the resolution is too small, the error of the pulse length detected by the count value = motor speed becomes large. For this reason, the next frequency division ratio is determined from the previous count value and the frequency division ratio so that the count value is larger than a predetermined lower reference value (β). The lower reference value is arbitrarily determined according to the required resolution.

  Specifically, the frequency dividing sequencer 2841, when the rotation speed of the motor becomes slow and exceeds a predetermined upper reference value, (current count value × current frequency dividing ratio) / predetermined lower reference value (β ) (= Preliminary frequency division ratio) The smallest integer value smaller than (set to the provisional frequency division ratio) is set as the next frequency division ratio. Note that the division ratio may not be the maximum integer value smaller than the provisional division ratio as long as it is smaller than the provisional division ratio and larger than the current division ratio.

  Next, a case where the rotational speed of the motor is increased will be described. As described in the case where the rotation speed of the motor becomes slow, if the period is excessive, the counter 2843 may overflow. For this reason, when it is expected that the rotation speed of the motor is slow, such as immediately after startup, the frequency division ratio is increased in advance.

  FIG. 32 is an explanatory diagram explaining the pulse period and the count value. The horizontal axis of the graph is time (t), and the vertical axis is the pulse detection voltage. As shown in the figure, when the rotation speed of the motor is increased, the pulse period is reduced, and the count value when the interval between pulses (α) is counted at a constant period is also reduced.

  FIG. 33 is a diagram showing the count value between pulses (α) when the pulse period becomes smaller. The horizontal axis of the graph is time (t), and the vertical axis is the count value. When the count value between pulses becomes smaller than the above-mentioned lower reference value (β), the error of the pulse length detected by the count value = the rotational speed of the motor increases. Therefore, the comparison unit 2845 determines whether or not the count value is smaller than a predetermined lower reference value (β). If the count value is smaller, the frequency division sequencer 2841 determines that the frequency division ratio is small. Determine the ratio.

  At this time, if an excessively small division ratio is determined, the same length is counted with a clock that is finer than necessary, so that the next count value may overflow. For this reason, the next frequency division ratio is determined so that the count value is smaller than a predetermined upper reference value (γ) from the previous count value and the frequency division ratio.

  Specifically, the frequency dividing sequencer 2841, when the rotation speed of the motor becomes faster and becomes smaller than a predetermined lower reference value, (current count value × current frequency dividing ratio) / predetermined upper reference value (γ ) (= The provisional frequency division ratio) is set to the smallest integer value larger than the provisional frequency division ratio as the next frequency division ratio. Note that the frequency division ratio need not be the smallest integer value larger than the temporary frequency division ratio as long as it is larger than the temporary frequency division ratio and smaller than the current frequency division ratio.

  When the count value is smaller than the predetermined upper reference value and larger than the predetermined lower reference value, the frequency dividing sequencer 2841 does not change the frequency dividing ratio and the current limiting process is executed.

  Next, details of the current limiting process in step S3106 will be described below. FIG. 34 is a flowchart showing the overall flow of the current limiting process in the fifth embodiment.

  First, the current limiting PWM circuit 2820 counts up the number of pulses of the PWM signal (step S3201). Next, the speed detection unit 2821 acquires a counter value from the counter 2843 of the adjustment circuit 2840 (step S3202), and counts up the number of counter values acquired (step S3203). Next, the speed detection unit 2821 adds the acquired count value as the time between pulse signals (step S3204).

  Since the average value calculation process, the duty setting process, and the parameter initialization process from step S3205 to step S3210 are the same as the process from step S1305 to step S1310 in the motor control device 200 according to the first embodiment, the description thereof will be given. Is omitted.

(Modification)
As described above, the frequency division sequencer 2841 divides the current count value, the current frequency division ratio, and a frequency that satisfies a predetermined condition determined from a predetermined upper reference value (γ) or a predetermined lower reference value (β). The ratio was calculated and set as the next division ratio. On the other hand, the frequency division sequencer 2841 may be configured to set the frequency division ratio changed at a predetermined ratio as the next frequency division ratio.

  In this case, the comparison unit 2844 first determines whether or not the count value is larger than the upper reference value. If the count value is larger, the frequency division sequencer 2841 sets the frequency division ratio larger by a predetermined ratio. For example, the frequency division sequencer 2841 sets the frequency division ratio to 2 times. When the count value is not larger than the upper reference value, the comparison unit 2845 determines whether or not the count value is smaller than the lower reference value.

  When the count value is smaller than the lower reference value, the frequency division sequencer 2841 decreases the frequency division ratio by a predetermined ratio. For example, the frequency division sequencer 2841 sets the frequency division ratio to ½. If the count value is not smaller than the lower reference value, the frequency dividing ratio is not changed and the current limiting process is executed. Since the flow of the current limiting process is the same as that of the fifth embodiment, the description thereof is omitted.

  FIG. 35 is an explanatory diagram showing an example of the relationship between the rotation speed and the count value in this modification. In the figure, immediately after startup, the counter clock is counted as a normal divide by 8, and the division ratio is changed to 4 divided, 2 divided, or 1 divided as the rotational speed increases. An example is shown. That is, at the start, the count value is measured by counting up with the clock divided by eight. When the rotation speed reaches a constant speed, it counts up by 4 and measures. Further, when the speed reaches a predetermined speed, the frequency is divided by 2, and finally counted up without frequency division. Thereby, even when the rotational speed is low, overflow of the counter can be avoided.

  FIG. 36 is an explanatory diagram showing the correspondence between the change in rotational speed and the temporal change in frequency division. As shown in the figure, in this embodiment, the adjustment circuit controls the frequency division ratio so that the frequency division ratio decreases as the rotational speed increases, and increases again when the speed decreases.

  Thus, in the fifth embodiment, the rotation speed is calculated using the time between the FG signals counted by adjusting the frequency division ratio by the adjustment circuit. Note that after calculating the rotation speed, a method of obtaining the PWM output value with reference to the speed-duty conversion table 151 as shown in FIG. 15 may be applied.

  As described above, in the motor control device according to the fifth embodiment and the modified embodiment, in order to increase the rotation speed measurement period at low speed rotation, the counter overflow is prevented, and at high speed rotation, the rotation speed measurement period is increased. In order to reduce the resolution, the resolution can be maintained at an arbitrary size or more.

  The motor control program executed by the motor control device according to the first to fifth embodiments is provided by being incorporated in advance in a ROM or the like.

  The motor control program executed by the motor control apparatus according to the first to fifth embodiments is a file in an installable format or an executable format, and is a CD-ROM, flexible disk (FD), CD-R, DVD. (Digital Versatile Disk) or the like may be provided by being recorded on a computer-readable recording medium.

  Further, the motor control program executed by the motor control apparatus according to the first to fifth embodiments is provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. It may be configured. Moreover, you may comprise so that the motor control program performed with the motor control apparatus concerning the 1st-5th embodiment may be provided or distributed via networks, such as the internet.

  The motor control program executed by the motor control device according to the first to fifth embodiments is a module including the above-described units (speed detection unit, averaging unit, current calculation unit, comparison unit, PWM output unit, etc.). As actual hardware, the CPU (processor) reads the motor control program from the ROM and executes it to load the above units onto the main memory, and the above units are generated on the main memory. It has come to be.

  As described above, the motor control device, the motor control method, the motor control program, and the image forming apparatus according to the present invention are the motor control device, the motor control method, the motor control program, and the image that control the driver that drives the motor by the PWM method. Suitable for forming equipment.

It is explanatory drawing which shows the structure of the image forming apparatus concerning this Embodiment. FIG. 3 is an explanatory diagram showing a configuration of a control system of the image forming apparatus according to the present embodiment. It is a block diagram which shows the structure of the motor control apparatus concerning the 1st Embodiment of this invention. It is a block diagram which shows the structure of the conventional motor control apparatus. It is explanatory drawing showing the timing chart of the PWM signal output with the PWM circuit of the conventional motor control apparatus. It is explanatory drawing which shows an example of the current waveform of the drive current which flows into the driver of the conventional motor control apparatus. It is explanatory drawing for demonstrating the principle utilized by this Embodiment. It is a graph which shows the relationship between a rotational speed and the electric current value which flows into a driver. It is explanatory drawing which showed the PWM duty limit value. It is explanatory drawing which showed the change of a rotational speed, a PWM instruction | indication value, and a PWM duty limit value. It is explanatory drawing which shows the relationship of the PWM output value actually output with respect to a PWM instruction | indication value and a PWM duty limit value. It is the block diagram which showed the detailed structure of the current limiting PWM circuit. It is a flowchart which shows the whole flow of the electric current limitation process in 1st Embodiment. It is the block diagram which showed another structure of the current limiting PWM circuit. It is a flowchart which shows the whole flow of the electric current limitation process in the modification of 1st Embodiment. It is the block diagram which showed the structure of the current limiting PWM circuit of the motor control apparatus concerning 2nd Embodiment. It is explanatory drawing which showed an example of the duty value of the PWM signal output in 2nd Embodiment. It is a flowchart which shows the whole flow of the duty determination process in 2nd Embodiment. It is explanatory drawing which showed the relationship between the rise of an electric current and the rise of a motor rotational speed. It is explanatory drawing which showed an example of the duty value of the PWM signal output in 3rd Embodiment. It is the block diagram which showed the structure of the current limiting PWM circuit of the motor control apparatus concerning 3rd Embodiment. It is a state transition diagram showing the relationship between activation modes. It is a flowchart which shows the whole flow of the duty determination process in 3rd Embodiment. It is a block diagram which shows the structure of the motor control apparatus concerning 4th Embodiment. It is explanatory drawing which showed an example of the output from the synthetic | combination Hall element. It is a block diagram which shows the structure of the motor control apparatus concerning 5th Embodiment. It is a block diagram which shows the detailed structure of a current limiting PWM circuit. It is a block diagram which shows the detailed structure of an adjustment circuit. It is a flowchart which shows the whole flow of the division ratio setting process in 5th Embodiment. It is explanatory drawing explaining the period and count value of a pulse. It is the figure which showed the count value between pulses ((alpha)) when the period of a pulse becomes large. It is explanatory drawing explaining the period and count value of a pulse. It is the figure which showed the count value of between pulses ((alpha)) when the period of a pulse becomes small. It is a flowchart which shows the whole flow of the current limiting process in 5th Embodiment. It is explanatory drawing which showed an example of the relationship between a rotational speed and a count value. It is explanatory drawing which showed the response | compatibility of the change of a rotational speed, and the time change of a frequency division.

Explanation of symbols

DESCRIPTION OF SYMBOLS 0 Developing unit 0a Toner cartridge 1 Developing roller 10 Image forming apparatus 11 Photosensitive belt 11a Surface 12 Charging means 13 Latent image forming means 13a Polygon mirror 13b f / θ lens 13c Reflecting mirror 14 Transfer means 14a Primary transfer device 14b Secondary transfer device DESCRIPTION OF SYMBOLS 15 Cleaning means 15a Photoconductor belt cleaning unit 16 Intermediate transfer belt 17 Conveyance roller 18 Fixing means 18a Heating roller 18b Pressure roller 19 Paper discharge roller 20 Paper discharge tray 21, 22, 23, 24 Clutch 25 Main motor 26 Transport motor 30 Operation Unit 31 LCD touch panel 32 Numeric keypad 33 Clear / Stop key 34 Print key 35 Preheating key 40 Main controller 120 Current limit PWM circuit 121 Speed detection unit 122 Averaging unit 123 Current Out section 124 comparison section 125 PWM output unit 130 the driver 131 three-phase output switching circuit 140 PID control circuit 151 Speed - duty conversion table 200 motor controller 211U, 211V, 211W winding 212 Hall element 213 FG
300 Motor Controller 320 PWM Circuit 330 Driver 331 Three-Phase Output Switching Circuit 332 Comparator 340 PID Control Circuit 1420 Current Limit PWM Circuit 1425 PWM Output Unit 1620 Current Limit PWM Circuit 1625 PWM Output Unit 1626 Timer 1627 Maximum Duty Determination Circuit 2120 Current Limit PWM Circuit 2125 PWM output unit 2127 Maximum duty determination circuit 2128 Sequencer 2400 Motor control device 2420 Current limit PWM circuit 2800 Motor control device 2820 Current limit PWM circuit 2821 Speed detection unit 2840 Adjustment circuit 2841 Frequency division sequencer 2842 Frequency division circuit 2843 Counter 2844 Comparison unit 2845 comparator

Claims (20)

  1. Control means for controlling a PWM signal for determining a voltage value to be supplied to the motor;
    And a driving means for driving the motor by applying a current corresponding to the voltage values Ru determined by the PWM signal to the windings of the motor,
    The control means includes
    Speed detecting means for detecting the rotational speed of the motor;
    Based on the rotational speed detected by the speed detection means after a predetermined first time and a predetermined second time from the lapse of the first time from the state where the motor is not rotating, An output means for outputting a PWM signal corresponding to a voltage value capable of energizing a current value that does not exceed a predetermined current limit value ;
    The output means outputs a PWM signal having a duty value larger than the duty value of the PWM signal output immediately after the second time elapses during the second time, and the second time during the first time. Outputting a PWM signal having a duty value larger than that of the output PWM signal;
    Motor control apparatus according to claim.
  2. The motor control device according to claim 1, wherein the first time is determined based on an electrical time constant of the winding.
  3. The motor control apparatus according to claim 1, wherein the output unit outputs a PWM signal that maximizes a voltage value during the first time period.
  4. The control means includes
    Calculating means for calculating a current value energized to the motor based on the rotational speed detected by the speed detecting means after the first time and the second time have elapsed ;
    Comparing means for comparing the calculated current value with the current limit value,
    The output means outputs a PWM signal for lowering the voltage value from the voltage value when the current value is calculated when the calculated current value is larger than the current limit value;
    The motor control device according to claim 1.
  5. The calculation means calculates a difference between the voltage value determined by the PWM signal and an induced voltage value corresponding to the detected rotation speed, and based on the calculated difference and the electrical resistance value of the winding Calculating the current value;
    The motor control device according to claim 4 .
  6. Further comprising an averaging means for calculating an average value of the plurality of rotation speeds detected by the speed detection means;
    The calculating means calculates the current value based on the calculated average value;
    The motor control device according to claim 4 .
  7. The output means outputs a PWM signal in which the voltage value is 0 when the calculated current value is larger than the current limit value;
    The motor control device according to claim 4 .
  8. The output means reduces the duty value of the PWM signal by a predetermined value when the calculated current value is larger than the current limit value;
    The motor control device according to claim 4 .
  9. And the rotational speed of the motor, further comprising a storage unit that stores an association and the duty value of the PWM signal corresponding to the voltage value that can be energized a current value does not exceed the current limit value,
    The output means acquires a PWM signal corresponding to the detected rotation speed from the storage unit, and outputs the acquired PWM signal;
    The motor control device according to claim 1.
  10. The speed detection means receives an input of a pulse signal corresponding to the number of rotations of the motor, and detects the rotation speed based on a time interval between the received pulse signals;
    The motor control device according to claim 1.
  11. The speed detecting means receives an input of the pulse signal which is an FG (Frequency Generator) signal having a frequency corresponding to the number of rotations of the motor;
    The motor control device according to claim 10 .
  12. The speed detection means receives the input of the pulse signal output from a Hall element that detects a magnetic pole position of a magnet constituting the motor;
    The motor control device according to claim 10 .
  13. The speed detecting means receives the input of the pulse signal output from the three Hall elements corresponding to each phase of the motor which is a three-phase motor;
    The motor control device according to claim 12 .
  14. A counter that counts a count value corresponding to the time interval based on a clock of a predetermined period;
    Count value comparing means for comparing the counted value with a predetermined upper limit value and a predetermined lower limit value;
    When the count value is larger than the upper limit value, a division ratio larger than the division ratio of the clock when the count value is counted is set, and when the count value is smaller than the lower limit value, the count value Frequency division ratio setting means for setting a frequency division ratio smaller than the frequency division ratio when counting
    Frequency division means for dividing the clock by the frequency division ratio set by the frequency division ratio setting means,
    The speed detecting means detects the rotational speed based on the count value counted by the divided clock;
    The motor control device according to claim 10 .
  15. The frequency division ratio setting means, when the count value is larger than the upper limit value, is less than or equal to a value obtained by dividing the product of the count value and the frequency division ratio when the count value is counted by the lower limit value, and Setting a frequency division ratio that is equal to or higher than the frequency division ratio when the count value is counted;
    15. The motor control device according to claim 14 ,
  16. When the count value is smaller than the lower limit value, the frequency division ratio setting means is equal to or greater than a value obtained by dividing the product of the count value and the frequency division ratio when the count value is counted by the upper limit value, and Setting a frequency division ratio equal to or less than the frequency division ratio when the count value is counted;
    The motor control device according to claim 14 .
  17. When the count value is greater than the upper limit value, the frequency division ratio setting unit multiplies the frequency division ratio when the count value is counted by a constant larger than 1, and the count value is less than the lower limit value. If smaller than the value, dividing the division ratio when the count value is counted by the constant,
    The motor control device according to claim 14 .
  18. A control step for controlling a PWM signal for determining a voltage value supplied to the motor by the control means;
    Drive means, and a driving step of driving the motor by applying a current corresponding to the voltage values Ru determined by the PWM signal to the windings of the motor,
    The control step includes
    A speed detecting step for detecting the rotational speed of the motor;
    Based on the rotation speed detected by the speed detection step after a predetermined first time and a predetermined second time have elapsed since the first time has elapsed since the motor is not rotating, An output step for outputting a PWM signal corresponding to a voltage value capable of energizing a current value that does not exceed a predetermined current limit value ,
    The output step outputs a PWM signal having a duty value larger than the duty value of the PWM signal output immediately after the second time elapses during the second time, and during the second time during the first time. Outputting a PWM signal having a duty value larger than that of the output PWM signal;
    The motor control method according to claim.
  19. A motor control program for causing a computer to execute the motor control method according to claim 18 .
  20. An image forming apparatus for forming a toner image on a transfer target,
    A conveying means which is rotatably held and conveys the transfer object;
    An image carrier for carrying a toner image formed to be held rotatably;
    Charging means for uniformly charging the surface of the image carrier;
    A latent image forming means for forming a latent image on the surface of the image carrier that is uniformly charged by the charging means;
    Developing means for visualizing the latent image formed by the latent image forming means;
    A transfer unit that is rotatably held and transfers the toner image visualized by the developing unit to the transfer target;
    It said conveying means, and a motor controller for controlling the driving of the motor for rotating at least one of the image bearing member, contact and said transfer means,
    The motor control device
    Control means for controlling a PWM signal for determining a voltage value to be supplied to the motor;
    Driving means for driving the motor by energizing the winding of the motor with a current corresponding to a voltage value determined by the PWM signal;
    The control means includes
    Speed detecting means for detecting the rotational speed of the motor;
    Based on the rotational speed detected by the speed detection means after a predetermined first time and a predetermined second time from the lapse of the first time from the state where the motor is not rotating, An output means for outputting a PWM signal corresponding to a voltage value capable of energizing a current value that does not exceed a predetermined current limit value;
    The output means outputs a PWM signal having a duty value larger than the duty value of the PWM signal output immediately after the second time elapses during the second time, and the second time during the first time. Outputting a PWM signal having a duty value larger than that of the output PWM signal;
    An image forming apparatus.
JP2007047646A 2006-09-27 2007-02-27 Motor control apparatus, motor control method, motor control program, and image forming apparatus Expired - Fee Related JP5250982B2 (en)

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JP2007047646A JP5250982B2 (en) 2006-09-27 2007-02-27 Motor control apparatus, motor control method, motor control program, and image forming apparatus
US12/068,411 US7911168B2 (en) 2007-02-27 2008-02-06 Method and device for controlling motor, and image forming apparatus
CN2008100741751A CN101257270B (en) 2007-02-27 2008-02-27 Method and device for controlling motor, and image forming apparatus

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JP6413756B2 (en) * 2014-12-24 2018-10-31 株式会社アドヴィックス Motor drive control device
JP6447874B2 (en) * 2015-08-25 2019-01-09 京セラドキュメントソリューションズ株式会社 Image forming apparatus
JP6497339B2 (en) * 2016-03-10 2019-04-10 京セラドキュメントソリューションズ株式会社 Motor control device, image forming apparatus, and motor control method
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