CN107026595B - motor speed regulation circuit, method and device - Google Patents
motor speed regulation circuit, method and device Download PDFInfo
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- CN107026595B CN107026595B CN201710474617.0A CN201710474617A CN107026595B CN 107026595 B CN107026595 B CN 107026595B CN 201710474617 A CN201710474617 A CN 201710474617A CN 107026595 B CN107026595 B CN 107026595B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/02—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the kind of motor
- H02P25/04—Single phase motors, e.g. capacitor motors
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Abstract
the invention discloses a motor speed regulation circuit, which comprises: the pulse generator comprises a first switch, a second switch, a first rectifying module, a second rectifying module and a pulse controller; when the first switch is closed and the second switch is opened, the first switch and the first rectifying module are connected in parallel at two ends of the motor, the voltage at two ends of the second switch is the input voltage of the motor, and the pulse controller adjusts the conducting duration of the first switch and the second switch in the current period according to the voltage detected by the detection end. The invention also discloses a motor speed regulation method and a motor speed regulation device. According to the invention, the voltage of the detection end of the pulse controller is compared with the preset voltage when the first switch is switched on and the second switch is switched off, and then the switching-on duration of the first switch and the switching-on duration of the second switch in the current period are adjusted, so that the current of the motor can be adjusted, the rotating speed of the motor is stabilized, and the phenomenon of unstable rotating speed caused by the fluctuation of mains supply voltage in the running process of the motor is avoided.
Description
Technical Field
the invention relates to the technical field of motors, in particular to a motor speed regulation circuit, a motor speed regulation method and a motor speed regulation device.
Background
In single-phase ac motor applications, it is often necessary to control the speed of the motor, and various single-phase ac motor speed control circuits have been developed. The speed regulating circuit of the currently common single-phase alternating-current motor is roughly as follows: the speed regulation by series inductance, capacitance, resistance, tap, frequency-variable speed regulation, and SCR.
according to the existing speed regulation control scheme for regulating the speed of the motor by adjusting the duty ratio of PWM, when the duty ratio of PWM is locked, if the input voltage (namely, mains voltage) changes, the rotating speed of the motor also changes correspondingly, so that the rotating speed of the motor at the same gear is unstable. For example, for a motor applied to a fan, before the fan leaves a factory, the rotation speed of the motor (i.e. the duty ratio of PWM) is preset for each gear, but when the input voltage (i.e. the mains voltage) changes, for example, when the mains voltage is 220V +/-15%, and the same PWM duty ratio is used, the rotation speed of the motor is different, and the fan may resonate, so that the noise of the fan is increased, and the user experience is seriously affected.
disclosure of Invention
The invention provides a motor speed regulation circuit, a motor speed regulation method and a motor speed regulation device, and aims to solve the technical problem that the rotating speed of a motor is unstable when the voltage of a mains supply changes.
in order to achieve the above object, the present invention provides a motor speed regulating circuit, including: the pulse generator comprises a first switch, a second switch, a first rectifying module, a second rectifying module and a pulse controller;
the input end of the first rectifying module is electrically connected with the input end of the motor, the output end of the first rectifying module is electrically connected with the output end of the motor, and the first switch is connected between the two load access ends of the first rectifying module; the input end of the second rectifying module is electrically connected with the output end of the motor, the output end of the second rectifying module is connected with a zero line, and the second switch is connected between two load access ends of the second rectifying module;
a first pulse output end of the pulse controller is electrically connected with the first switch and is used for controlling the on and off of the first switch; a second pulse output end of the pulse controller is electrically connected with the second switch and is used for controlling the second switch to be switched on and off; the detection end of the pulse controller is used for detecting the voltage at two ends of the second switch;
when the first switch is closed and the second switch is opened, the first switch and the first rectifying module are connected in parallel at two ends of the motor, the voltage at two ends of the second switch is the input voltage of the motor, and the pulse controller adjusts the conducting time of the first switch and the second switch in the current period according to the voltage detected by the detection end.
preferably, the first switch is a first mos tube, and the first switch is a second mos tube;
The grid electrode of the first mos tube is electrically connected with the first pulse output end of the pulse controller, the grid electrode of the second mos tube is electrically connected with the second pulse output end of the pulse controller, and the drain electrode of the second mos tube is electrically connected with the detection end of the pulse controller.
Preferably, the first rectifier module comprises a first rectifier bridge and the second rectifier module comprises a second rectifier bridge;
The first rectifier bridge comprises a diode D1, a diode D2, a diode D3, and a diode D4; the anode of the diode D1 is connected with the cathode of the diode D2 and the input end of the motor respectively, the cathode of the diode D3 is connected with the anode of the diode D4 and the output end of the motor respectively, the cathode of the diode D1 is connected with the cathode of the diode D4 and the drain of the first mos tube respectively, and the anode of the diode D2 is connected with the anode of the diode D3 and the source of the first mos tube respectively;
The second rectifier bridge comprises a diode D5, a diode D6, a diode D7, and a diode D8; the anode of the diode D5 is connected with the cathode of the diode D6 and the output end of the motor respectively, the cathode of the diode D7 is connected with the anode of the diode D8 and the zero line respectively, and the cathode of the diode D5 is connected with the cathode of the diode D8 and the drain of the second mos tube respectively; the anode of the diode D6 is connected to the anode of the diode D7 and the source of the second mos transistor, respectively.
Preferably, the motor speed regulation circuit is further provided with a series voltage division circuit comprising a first resistor and a second resistor; one end of the series voltage division circuit is connected with the drain electrode of the second mos tube, and the other end of the series voltage division circuit is connected with the source electrode of the second mos tube; the detection end is electrically connected with a node at the joint of the first resistor and the second resistor and is used for detecting the voltage at two ends of the second resistor.
Preferably, the gate of the first mos transistor is electrically connected to the first pulse output terminal through an off-electric coupler.
In addition, in order to achieve the above object, the present invention further provides a motor speed regulating method, which adopts any one of the above motor speed regulating circuits, and the motor speed regulating method includes the following steps:
When the first switch is turned on and the second switch is turned off, the pulse controller acquires the voltage of the detection end;
Determining whether the acquired voltage is equal to a preset voltage;
When the acquired voltage is not equal to a preset voltage, adjusting the on-time of the first switch and the on-time of the second switch in the current period based on the acquired voltage and the preset voltage.
preferably, the step of adjusting the on-time of the first switch and the on-time of the second switch in the current period based on the acquired voltage and a preset voltage includes:
Calculating the voltage difference between the acquired voltage and the preset voltage;
calculating a voltage ratio between the voltage difference and the preset voltage;
and when the acquired voltage is greater than the preset voltage, increasing the conduction time of the first switch in the current period and reducing the conduction time of the second switch in the current period based on the voltage ratio.
Preferably, after the step of calculating the voltage ratio between the voltage difference and the preset voltage, the method further includes:
when the acquired voltage is smaller than the preset voltage, reducing the conduction time of the first switch in the current period and increasing the conduction time of the second switch in the current period based on the voltage ratio.
Preferably, when the first switch is a first mos transistor and the first switch is a second mos transistor, the step of obtaining the voltage at the detection end of the pulse controller when the first switch is turned on and the second switch is turned off includes:
and when the first mos tube is conducted and the second mos tube is cut off, delaying a preset time interval to obtain the voltage of the detection end.
In addition, in order to achieve the above object, the present invention further provides a motor speed adjusting device, which uses the motor speed adjusting circuit described in any one of the above, the motor speed adjusting device including: a memory and a motor speed regulation program stored on the memory and operable on the pulse controller, wherein:
The motor speed regulating program is executed by the pulse controller to realize the steps of the motor speed regulating method.
According to the motor speed regulating circuit, the voltage of the detection end of the pulse controller is compared with the preset voltage when the first switch is switched on and the second switch is switched off, and then the switching-on duration of the first switch and the switching-on duration of the second switch in the current period are adjusted, so that the current of the motor can be adjusted, the rotating speed of the motor is stabilized, and the phenomenon of unstable rotating speed caused by the fluctuation of mains supply voltage in the operation process of the motor is avoided.
drawings
FIG. 1 is a schematic diagram of a circuit structure in an embodiment of a motor speed regulation circuit according to the present invention;
FIG. 2 is a schematic flow chart of a first embodiment of a motor speed control method according to the present invention;
fig. 3 is a detailed flowchart of a step of adjusting the on-time of the first switch and the on-time of the second switch in the current period based on the acquired voltage and the preset voltage in the second embodiment of the motor speed regulating method of the present invention.
The reference numbers illustrate:
| First switch K1 | second switch K2 | First rectifier module 10 | Second rectifier module 20 |
| Pulse controller 30 | Motor M | Diode D1 | Diode D2 |
| Diode D3 | Diode D4 | Diode D5 | Diode D6 |
| diode D7 | diode D8 | First resistor RV1 | Second resistor RV2 |
| Power-off coupler P1 |
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The invention provides a motor speed regulation circuit. Referring to fig. 1, fig. 1 is a schematic circuit structure diagram of an embodiment of a motor speed regulating circuit of the present invention.
in this embodiment, the motor speed regulation circuit includes: a first switch K1, a second switch K2, a first rectification module 10, a second rectification module 20 and a pulse controller 30.
the input end of the first rectifying module 10 is electrically connected with the input end of the motor M, the output end of the first rectifying module 10 is electrically connected with the output end of the motor M, and the first switch K1 is connected between the two load access ends of the first rectifying module; the input end of the second rectifying module 20 is electrically connected with the output end of the motor M, the output end of the second rectifying module 20 is connected with a zero line, and the second switch K2 is connected between two load access ends of the second rectifying module 20.
In this embodiment, the first switch K1 and the second switch K2 may be transistors, mos transistors, or the like. The first rectifying module 10 and the second rectifying module 20 may be bridge rectifying circuits, i.e. rectifying bridges. When the first switch K1 is closed, the first switch K1 is connected to the first rectifying module 10 and then connected in parallel to two ends of the motor M, so that the motor M is short-circuited, that is, current flows into the second rectifying module 20 after flowing through the first switch K1 and the first rectifying module 10, and if the second switch K2 is disconnected at this time, current flows to one end of the second switch K2 through the second rectifying module 20, so that the voltage at two ends of the second switch K2 is the input voltage of the motor M. That is, when the first switch K1 is closed and the second switch K2 is opened, the first switch K1 and the first rectification module 10 are connected in parallel across the motor M, and the voltage across the second switch K2 is the input voltage of the motor M.
a first pulse output end of the pulse controller 30 is electrically connected with the first switch K1 and is used for controlling the on and off of the first switch K1; a second pulse output end of the pulse controller 30 is electrically connected with the second switch K2 and is used for controlling the on and off of the second switch K2; the sensing terminal of the pulse controller 30 is used for sensing the voltage across the second switch K2. When the first switch K1 is closed and the second switch K2 is opened, the pulse controller 30 adjusts the on-time of the first switch K1 and the second switch K2 in the current cycle according to the voltage detected by the detection terminal.
In the present embodiment, the specific process of the pulse controller 30 controlling the first switch K1 and the second switch K2 to be turned on and off includes: when the pulse controller 30 controls the first switch K1 to be closed through the first pulse output end, the second switch K2 is controlled to be opened through the second pulse output end; when the pulse controller 30 controls the first switch K1 to be opened through the first pulse output terminal, the second switch K2 is controlled to be closed through the second pulse output terminal. When the first switch K1 is turned off and the second switch K2 is turned on, current flows to the zero line through the motor M, the second rectifier module 20 and the second switch K2, so that the motor M works normally; when the first switch K1 is closed and the second switch K2 is open, the current flows to one end of the second switch K2 through the first rectifier module 10, the first switch K1 and the second rectifier module 20, so that the motor M is short-circuited, and the voltage across the second switch K2 is the current input voltage, i.e., the current mains voltage.
Therefore, when the first switch K1 is closed and the second switch K2 is opened, the voltage detected by the detection end of the pulse controller 30 can adjust the on-time of the first switch K1 and the second switch K2 in the current period, and further adjust the current of the motor M, so that when the input voltage (mains voltage) fluctuates, the motor M can work at a stable rotation speed, and the phenomenon of unstable rotation speed caused by the fluctuation of the mains voltage in the running process of the motor M is avoided.
for example, if the first switch K1 is closed and the second switch K2 is opened, the voltage detected by the detection terminal is 265V, and the difference between the detected voltage and the preset voltage is: and the ratio of the difference value to the preset voltage is as follows: 46V/311V is 15%, so that the on-time of the second switch K2 in the current period is increased by 15%, that is, adjusted to 115% of the original on-time, the on-time of the first switch K1 in the current period is set to be the new on-time, which is the original on-time of the first switch K1-the original on-time of the second switch K2-15%, and then the on-time of the second switch K2 is increased, and the on-time of the first switch K1 is decreased, so as to increase the current of the motor M, and enable the motor M to operate at a stable rotation speed. If the first switch K1 is closed and the second switch K2 is open, the voltage detected by the detection terminal is 357V, and the difference between the detected voltage and the preset voltage is: 357V-311V-47V, the ratio of the difference to the preset voltage is: therefore, the on-time of the second switch K2 in the current period is reduced by 15%, that is, adjusted to 85% of the original on-time, the on-time of the first switch K1 in the current period is set to be the new on-time, which is the original on-time of the first switch K1 + the original on-time of the second switch K2 × 15%, so as to increase the on-time of the first switch K1 and reduce the on-time of the second switch K2, thereby reducing the current of the motor M, and enabling the motor M to operate at a stable rotation speed. When the preset voltage is 220V, the voltage across the second switch K2 may be specifically set to 311V.
Further, in an embodiment, the first switch K1 is a first mos transistor, and the first switch K1 is a second mos transistor.
the grid electrode of the first mos tube is electrically connected with the first pulse output end of the pulse controller 30, the grid electrode of the second mos tube is electrically connected with the second pulse output end of the pulse controller 30, and the drain electrode of the second mos tube is electrically connected with the detection end of the pulse controller 30.
the first mos tube and the second mos tube may be n-channel mos tubes or p-channel mos tubes, and in this embodiment, the first mos tube and the second mos tube are both n-channel mos tubes. The pulse controller 30 controls the conduction and the cut-off of the first mos tube and the second mos tube through PWM, specifically, for example, when the first mos tube and the second mos tube are both n-channel mos tubes, a high level is output at a first pulse output end of the pulse controller 30 to conduct the first mos tube, and a low level is output at a second pulse output end to cut-off the second mos tube, so that the second mos tube is cut-off when the first mos tube is conducted; a low level is output at the first pulse output end of the pulse controller 30 to stop the first mos tube, and a high level is output at the second pulse output end to turn on the second mos tube, and when the first mos tube is stopped, the second mos tube is turned on.
When the first mos tube is an n-channel mos tube, the source electrode of the first mos tube is connected with a virtual ground, when the first pulse output end outputs a high level, the source electrode of the first mos tube is grounded through the virtual ground, and then the high voltage of the grid electrode of the first mos tube can enable the drain electrode and the source electrode of the first mos tube to be conducted, namely the first mos tube is conducted, and when the first mos tube is conducted, the source electrode of the first mos tube is disconnected from the virtual ground. When the first mos tube is a p-channel mos tube, the source electrode of the first mos tube is connected with a virtual high level with voltage larger than the output voltage of the first pulse output end, and then the high voltage of the grid electrode of the first mos tube can enable the drain electrode of the first mos tube to be conducted with the source electrode, namely the first mos tube is conducted, and when the first mos tube is conducted, the source electrode of the first mos tube is disconnected with the virtual high level. When the second mos tube is an n-channel mos tube, the source electrode of the second mos tube is connected with a virtual ground, when the second pulse output end outputs a high level, the source electrode of the second mos tube is grounded through the virtual ground, and further, the high voltage of the grid electrode of the second mos tube can enable conduction between the drain electrode and the source electrode of the second mos tube, namely, the second mos tube is conducted, and when the second mos tube is conducted, the source electrode of the second mos tube is disconnected from the virtual ground. When the second mos tube is a p-channel mos tube, the source electrode of the second mos tube is connected with a virtual high level with voltage larger than the output voltage of the first pulse output end, and then the high voltage of the grid electrode of the second mos tube can enable the drain electrode of the second mos tube to be conducted with the source electrode, namely the second mos tube is conducted, and when the second mos tube is conducted, the source electrode of the second mos tube is disconnected with the virtual high level.
preferably, the first rectifier module 10 comprises a first rectifier bridge and the second rectifier module 20 comprises a second rectifier bridge.
the first rectifier bridge comprises a diode D1, a diode D2, a diode D3 and a diode D4, wherein the anode of the diode D1 is connected with the cathode of the diode D2 and the input end of the motor M, the cathode of the diode D3 is connected with the anode of the diode D4 and the output end of the motor M, the cathode of the diode D1 is connected with the cathode of the diode D4 and the drain of the first mos tube, and the anode of the diode D2 is connected with the anode of the diode D3 and the source of the first mos tube.
The diode D1, the diode D2, the diode D3, and the diode D4 are all rectifier diodes. The input end of the first rectifying module 10 is a node at a junction of anodes of the diodes D1 and a cathode of the diode D2, respectively, a junction of a cathode of the diode D3 at the output end of the first rectifying module 10 and an anode of the diode D4, respectively, and the two load access ends are nodes at a junction of a cathode of the diode D1 and a cathode of the diode D4, respectively, and a junction of an anode of the diode D2 and an anode of the diode D3, respectively.
In this embodiment, when the first mos transistor is turned on, if the input terminal of the motor M is a forward voltage, a current flows through the diode D1, the first mos transistor and the diode D3, the motor M is short-circuited through the diode D1, the first mos transistor and the diode D3, and the current directly flows into the second rectifier bridge and is discharged to a back-emf of the motor M; if the input end of the motor M is reverse voltage, current flows through the diode D2, the first mos tube and the diode D4, the motor M is short-circuited through the diode D2, the first mos tube and the diode D4, and the current directly flows into the second rectifier bridge and is discharged to the back potential of the motor M.
The second rectifier bridge comprises a diode D5, a diode D6, a diode D7 and a diode D8, the anode of the diode D5 is connected with the cathode of the diode D6 and the output end of the motor M respectively, the cathode of the diode D7 is connected with the anode of the diode D8 and the zero line respectively, and the cathode of the diode D5 is connected with the cathode of the diode D8 and the drain of the second mos tube respectively; the anode of the diode D6 is connected to the anode of the diode D7 and the source of the second mos transistor, respectively.
The diode D5, the diode D6, the diode D7, and the diode D8 are all rectifier diodes. The input end of the second rectifying module 20 is a node at a junction of the anodes of the diodes D5 and D6, the output end of the second rectifying module 20 is a node at a junction of the cathodes of the diodes D7 and the anode of the diode D8, and the second switch K2 is connected to a node at a junction of the two load access ends of the second rectifying module 20, the two load access ends of the second rectifying module 20 are a junction of the cathodes of the diodes D5 and the cathodes of the diodes D8, and a node at a junction of the anodes of the diodes D6 and the anode of the diode D7.
In this embodiment, when the first mos transistor is turned on, the second mos transistor is turned off, if the input terminal of the motor M is a forward voltage, a current flows to the drain of the second mos transistor through the diode D6, so that a voltage between the drain and the source of the second mos transistor is a mains voltage, and if the input terminal of the motor M is a reverse voltage, the current flows to the source of the second mos transistor through the diode D7, so that a voltage between the drain and the source of the second mos transistor is a mains voltage. And then the voltage between the drain electrode and the source electrode of the second mos tube can be compared with a preset voltage, so that the conduction time of the first mos tube and the conduction time of the second mos tube in the current period can be adjusted according to the comparison result, the current of the motor M can be adjusted, and the rotating speed of the motor M can be stabilized.
further, in an embodiment, the motor speed regulation circuit is further provided with a series voltage division circuit comprising a first resistor RV1 and a second resistor RV 2; one end of the series voltage division circuit is connected with a drain electrode of the second mos tube, and the other end of the series voltage division circuit is connected with a source electrode of the second mos tube; the detection end is electrically connected with a node at the joint of the first resistor RV1 and the second resistor RV2 and is used for detecting the voltage at two ends of the second resistor RV 2.
the first resistor RV1 is greater than the second resistor RV2, for example, the first resistor RV1 is 1020K Ω, and the second resistor RV2 is 5.1K Ω, and of course, the resistances of the first resistor RV1 and the second resistor RV2 may also be set reasonably according to actual parameters of the pulse controller 30.
In this embodiment, the voltage dividing effect of the first resistor RV1 and the second resistor RV2, and the detection voltage when the detection end is used for detecting the voltage at the two ends of the second resistor RV2 are small, so that the requirement of the pulse controller 30 can be reduced. In one embodiment, to ensure the voltage across the second resistor RV2 to be stable, a capacitor CV1 is connected in parallel across the second resistor RV2
For example, when the first resistor RV1 is 1020K Ω and the second resistor RV2 is 5.1K Ω, if the first mos transistor is closed and the second mos transistor is open, the voltage detected by the detection terminal is 1.32V, and the difference between the detected voltage and the preset voltage is: 1.55V-1.32V ═ 0.23V, the ratio of this difference to the preset voltage is: 0.23V/1.55V is 15%, so that the conduction time of the second mos tube in the current period is increased by 15%, that is, adjusted to 115% of the original conduction time, the conduction time of the first mos tube in the current period is set to be a new conduction time, the new conduction time is the original conduction time of the first mos tube-the original conduction time of the second mos tube-15%, and then the conduction time of the second mos tube is increased, and the conduction time of the first mos tube is reduced, so as to increase the current of the motor M, so that the motor M can operate at a stable rotation speed; if the first mos tube is closed and the second mos tube is disconnected, the voltage detected by the detection end is 1.87V, and the difference value between the detected voltage and the preset voltage is as follows: 1.87V-1.55V ═ 0.23V, the ratio of this difference to the preset voltage is: 0.23V/1.55V is 15%, so that the conduction time of the second mos tube in the current period is reduced by 15%, that is, adjusted to 85% of the original conduction time, the conduction time of the first mos tube in the current period is set to be a new conduction time, the new conduction time is the original conduction time of the first mos tube + the original conduction time of the second mos tube by 15%, and further the conduction time of the first mos tube is increased, and the conduction time of the second mos tube is reduced, so that the current of the motor M is reduced, and the motor M can operate at a stable rotation speed. When the preset voltage is 220V, the voltage across the second resistor RV2 may be specifically set to 1.55V.
Preferably, the gate of the first mos transistor is electrically connected to the first pulse output terminal through an off-electrical coupler P1. So as to improve the efficiency when the first mos tube is switched on or off. In one embodiment, the power-off coupler P1 is electrically connected to the first pulse output terminal through a resistor, and the second mos transistor is electrically connected to the second pulse output terminal through a resistor.
Preferably, the motor speed regulation circuit is further provided with a third resistor RM1 and a capacitor CM1, and the third resistor RM1 is connected in series with the capacitor CM1 and then connected in parallel to two ends of the motor M. When the first mos tube is switched from off to on, the motor M is buffered.
When the first switch K1 is turned on and the second switch K2 is turned off, the voltage of the detection end of the pulse controller 30 is the current mains voltage, the voltage is compared with the preset voltage, and then the on-time of the first switch K1 and the on-time of the second switch K2 in the current period are adjusted, so that the current of the motor M can be adjusted, the rotating speed of the motor M is stabilized, and the phenomenon that the rotating speed is unstable due to the fluctuation of the mains voltage in the operation process of the motor M is avoided.
The invention further provides a motor speed regulating method. Referring to fig. 2, fig. 2 is a schematic flow chart of a first embodiment of the motor speed regulating method of the present invention.
In this embodiment, the motor speed control method adopts the motor speed control circuit of the above embodiment. The method comprises the following steps:
Step S10, when the first switch K1 is turned on and the second switch K2 is turned off, the pulse controller 30 obtains the voltage of the detection terminal;
In this embodiment, when the first switch K1 is closed, the first switch K1 is connected to the first rectification module 10 and then connected in parallel to two ends of the motor M, so that the motor M is short-circuited, that is, current flows into the second rectification module 20 after flowing through the first switch K1 and the first rectification module 10, and if the second switch K2 is disconnected, current flows to one end of the second switch K2 through the second rectification module 20, so that the voltage at two ends of the second switch K2 is the input voltage of the motor M.
if the first switch K1 is a first mos transistor, the first switch K1 is a second mos transistor, the first rectifying module 10 includes a first rectifying bridge, and the second rectifying module 20 includes a second rectifying bridge, when the first mos transistor is turned on and the second mos transistor is turned off, if the input end of the motor M is a forward voltage, a current flows through the diode D1, the first mos transistor and the diode D3, the motor M is short-circuited through the diode D1, the first mos transistor and the diode D3, the current directly flows into the second rectifying bridge, and simultaneously a back-emf of the motor M is discharged, and the current flows through the diode D6 to a drain of the second mos transistor, so that a voltage between the drain and a source of the second mos transistor is a mains voltage; if the input end of the motor M is reverse voltage, current flows through the diode D2, the first mos tube and the diode D4, the motor M is further short-circuited through the diode D2, the first mos tube and the diode D4, the current directly flows into the second rectifier bridge, the back potential of the motor M is discharged, and the current flows to the source electrode of the second mos tube through the diode D7, so that the voltage between the drain electrode and the source electrode of the second mos tube is mains supply voltage; the detection voltage of the detection end of the pulse controller 30 is the voltage between the drain and the source of the second mos transistor, so that when the first mos transistor is turned on and the second mos transistor is turned off, the voltage of the detection end of the pulse controller 30 is the current mains voltage.
Step S20, determining whether the acquired voltage is equal to a preset voltage;
When the preset voltage is 220V, the voltage across the second switch K2 may be specifically set to 311V. When the motor speed regulation circuit is further provided with a series voltage division circuit comprising a first resistor RV1 and a second resistor RV2, when the preset voltage is 220V, the voltage across the second resistor RV2 may be specifically set to 1.55V, wherein the first resistor RV1 is greater than the second resistor RV2, for example, the first resistor RV1 is 1020K Ω, and the second resistor RV2 is 5.1K Ω.
When the voltage at the detection end is obtained, the pulse controller 30 determines whether the obtained voltage is equal to a preset voltage, and further determines whether the current input voltage (mains voltage) fluctuates, wherein when the obtained voltage is not equal to the preset voltage, the current input voltage (mains voltage) fluctuates, and if the current PWM is continuously used to control the first switch K1 and the second switch K2, the rotation speed of the motor M may be unstable.
In step S30, when the acquired voltage is not equal to a preset voltage, the on duration of the first switch K1 and the on duration of the second switch K2 in the current period are adjusted based on the acquired voltage and the preset voltage.
in this embodiment, when the obtained voltage is not equal to the preset voltage, the pulse controller 30 adjusts the on-time of the first switch K1 and the on-time of the second switch K2 in the current period based on the obtained voltage and the preset voltage, for example, when the obtained voltage is greater than the preset voltage, the pulse controller 30 increases the on-time of the first switch K1 and decreases the on-time of the second switch K2 based on the obtained voltage and the preset voltage, and when the obtained voltage is less than the preset voltage, the pulse controller 30 decreases the on-time of the first switch K1 and increases the on-time of the second switch K2 based on the obtained voltage and the preset voltage, and further adjusts the current of the motor M, so that the motor M can operate at a stable rotation speed when the input voltage (mains voltage) fluctuates.
Further, in an embodiment, when the first switch K1 is a first mos transistor and the first switch K1 is a second mos transistor, the step S10 includes:
And when the first mos tube is conducted and the second mos tube is cut off, delaying a preset time interval to obtain the voltage of the detection end.
In this embodiment, after the second mos transistor is turned off, the voltage across the second mos transistor gradually rises until stabilization, so that the accuracy of adjusting the on-time of the first switch K1 by one stage of the on-time of the second switch K2 is improved by delaying the preset time interval to acquire the voltage across the second mos transistor after the voltage across the second mos transistor is stabilized, and the stability of the rotation speed of the motor M is further improved.
According to the motor speed regulation method provided by the embodiment, when the first switch K1 is switched on and the second switch K2 is switched off, the pulse controller 30 acquires the voltage of the detection end, then determines whether the acquired voltage is equal to the preset voltage, and then adjusts the on duration of the first switch K1 and the on duration of the second switch K2 in the current period based on the acquired voltage and the preset voltage when the acquired voltage is not equal to the preset voltage, so that the on duration of the first switch K1 and the on duration of the second switch K2 in the current period can be adjusted through the voltage of the detection end and the preset voltage, the current of the motor M is further adjusted, the rotating speed of the motor M is stabilized, and the phenomenon that the rotating speed is unstable due to the fluctuation of mains supply voltage in the operation process of the motor M is avoided.
Based on the first embodiment, a second embodiment of the motor speed regulating method of the present invention is proposed, and referring to fig. 3, in this embodiment, step S30 includes:
Step S31, calculating a voltage difference between the acquired voltage and the preset voltage;
Step S32, calculating a voltage ratio between the voltage difference and the preset voltage;
Step S33, when the obtained voltage is greater than the preset voltage, increasing the on-time of the first switch K1 in the current period and decreasing the on-time of the second switch K2 in the current period based on the voltage ratio.
in this embodiment, if the voltage detected by the detection terminal is 357V, the voltage difference between the detected voltage and the preset voltage is: 357V-311V is 47V, and the ratio of the voltage difference to the preset voltage, i.e. the voltage ratio, is: when the voltage ratio is 15%, the procedure of increasing the on-time of the first switch K1 in the current period and decreasing the on-time of the second switch K2 in the current period based on the voltage ratio specifically includes: reducing the conducting time of the second switch K2 in the current period by 15%, namely adjusting to 85% of the original conducting time, setting the conducting time of the first switch K1 in the current period as a new conducting time, wherein the new conducting time is the original conducting time of the first switch K1 + the original conducting time of the second switch K2 by 15%, further increasing the conducting time of the first switch K1, and reducing the conducting time of the second switch K2, so as to reduce the current of the motor M, so that the motor M can work at a stable rotating speed. When the preset voltage is 220V, the voltage across the second switch K2 may be specifically set to 311V.
In another embodiment, the motor speed regulation circuit further includes a series voltage divider circuit including a first resistor RV1 and a second resistor RV2, for example, when the first resistor RV1 is 1020K Ω and the second resistor RV2 is 5.1K Ω, if the voltage detected by the detection terminal is 1.87V, the voltage difference between the detected voltage and the preset voltage is: 1.87V-1.55V ═ 0.23V, and then the ratio of the voltage difference to the preset voltage, i.e. the voltage ratio, is: therefore, the procedure of increasing the on-duration of the first switch K1 in the current period and decreasing the on-duration of the second switch K2 in the current period based on the voltage ratio includes: reducing the conduction time of the second mos tube in the current period by 15%, namely adjusting the conduction time to 85% of the original conduction time, setting the conduction time of the first mos tube in the current period as new conduction time, wherein the new conduction time is equal to the original conduction time of the first mos tube plus the original conduction time of the second mos tube by 15%, further increasing the conduction time of the first mos tube, reducing the conduction time of the second mos tube, so as to reduce the current of the motor M, and enable the motor M to work at a stable rotating speed. When the preset voltage is 220V, the voltage across the second resistor RV2 may be specifically set to 1.55V.
Further, in an embodiment, after step S32, the method further includes:
when the acquired voltage is smaller than the preset voltage, the on-time of the first switch K1 in the current period is reduced and the on-time of the second switch K2 in the current period is increased based on the voltage ratio.
In this embodiment, if the voltage detected by the detecting terminal is 265V, the voltage difference between the detected voltage and the preset voltage is: the voltage ratio of the voltage difference to the preset voltage, namely the voltage ratio, is as follows: therefore, the procedure of increasing the on-duration of the first switch K1 in the current period and decreasing the on-duration of the second switch K2 in the current period based on the voltage ratio specifically includes: the on-time of the second switch K2 in the current period is increased by 15%, that is, adjusted to 115% of the original on-time, the on-time of the first switch K1 in the current period is set as a new on-time, the new on-time is the original on-time of the first switch K1-the original on-time of the second switch K2 is 15%, and then the on-time of the second switch K2 is increased, and the on-time of the first switch K1 is reduced, so as to improve the current of the motor M, so that the motor M can operate at a stable rotation speed. When the preset voltage is 220V, the voltage across the second switch K2 may be specifically set to 311V.
In another embodiment, the motor speed regulation circuit further includes a series voltage divider circuit including a first resistor RV1 and a second resistor RV2, for example, when the first resistor RV1 is 1020K Ω and the second resistor RV2 is 5.1K Ω, if the voltage detected at the detection end is 1.32V, the voltage difference between the detected voltage and the preset voltage is: 1.55V-1.32V ═ 0.23V, and the ratio of the voltage difference to the preset voltage, i.e. the voltage ratio, is: therefore, the procedure of increasing the on-duration of the first switch K1 in the current period and decreasing the on-duration of the second switch K2 in the current period based on the voltage ratio includes: the conduction time of the second mos tube in the current period is increased by 15%, namely adjusted to 115% of the original conduction time, the conduction time of the first mos tube in the current period is set to be a new conduction time, the new conduction time is equal to the original conduction time of the first mos tube-the original conduction time of the second mos tube by 15%, the conduction time of the second mos tube is further increased, the conduction time of the first mos tube is reduced, the current of the motor M is improved, and the motor M can work at a stable rotating speed. When the preset voltage is 220V, the voltage across the second resistor RV2 may be specifically set to 1.55V.
According to the motor speed regulation method provided by the embodiment, the voltage obtained by calculation and the voltage difference between the preset voltages are calculated, then the voltage ratio between the voltage difference and the preset voltages is calculated, and then when the obtained voltage is greater than the preset voltage, the conduction time of the first switch K1 in the current period is increased and the conduction time of the second switch K2 in the current period is reduced based on the voltage ratio, so that the conduction time of the first switch K1 and the second switch K2 is accurately adjusted according to the obtained voltage and the preset voltage, the adjustment accuracy and the accuracy of the conduction time of the first switch K1 and the second switch K2 are improved, the stability of the rotating speed of the motor M is improved, and the phenomenon that the rotating speed is unstable due to the fluctuation of the mains supply voltage in the operation process of the motor M is avoided.
The invention further provides a motor speed regulating device.
In this embodiment, the motor speed adjusting device adopts the motor speed adjusting circuit of the above embodiment, and the motor speed adjusting device includes: a memory and a motor speed regulation program stored in the memory and operable on the pulse controller 30, and the pulse controller 30 may be configured to call the motor speed regulation program stored in the memory and perform the following operations:
when the first switch K1 is turned on and the second switch K2 is turned off, the pulse controller 30 obtains the voltage of the detection end;
Determining whether the acquired voltage is equal to a preset voltage;
When the acquired voltage is not equal to a preset voltage, adjusting the on-time of the first switch K1 and the on-time of the second switch K2 in the current period based on the acquired voltage and the preset voltage.
further, the pulse controller 30 may be configured to invoke a motor speed regulation program stored in the memory, and further perform the following operations:
Calculating the voltage difference between the acquired voltage and the preset voltage;
Calculating a voltage ratio between the voltage difference and the preset voltage;
when the acquired voltage is greater than the preset voltage, increasing the on-time of the first switch K1 in the current period and decreasing the on-time of the second switch K2 in the current period based on the voltage ratio.
further, the pulse controller 30 may be configured to invoke a motor speed regulation program stored in the memory, and further perform the following operations:
When the acquired voltage is smaller than the preset voltage, the on-time of the first switch K1 in the current period is reduced and the on-time of the second switch K2 in the current period is increased based on the voltage ratio.
Further, the pulse controller 30 may be configured to invoke a motor speed regulation program stored in the memory, and further perform the following operations:
And when the first mos tube is conducted and the second mos tube is cut off, delaying a preset time interval to obtain the voltage of the detection end.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or system that comprises the element.
the above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
through the above description of the embodiments, those skilled in the art will clearly understand that the method of the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but in many cases, the former is a better implementation manner. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which is stored in a storage medium (such as ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal device (such as a mobile phone, a computer, a server, an air conditioner, or a network device) to execute the method according to the embodiments of the present invention.
the above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (9)
1. A motor speed regulation circuit, the motor speed regulation circuit comprising: the pulse generator comprises a first switch, a second switch, a first rectifying module, a second rectifying module and a pulse controller;
the input end of the first rectifying module is connected with the input end of the motor, the output end of the first rectifying module is connected with the output end of the motor, and the first switch is connected between the two load access ends of the first rectifying module; the input end of the second rectifying module is connected with the output end of the motor, the output end of the second rectifying module is connected with a zero line, and the second switch is connected between two load access ends of the second rectifying module;
a first pulse output end of the pulse controller is connected with the first switch and used for controlling the on and off of the first switch; a second pulse output end of the pulse controller is connected with the second switch and is used for controlling the second switch to be switched on and switched off; the detection end of the pulse controller is used for detecting the voltage at two ends of the second switch;
When the first switch is closed and the second switch is opened, the first switch and the first rectifying module are connected in parallel at two ends of the motor, and the voltage at two ends of the second switch is the input voltage of the motor;
The pulse controller acquires the voltage of the detection end and calculates a voltage ratio based on the voltage of the detection end;
When the acquired voltage is larger than a preset voltage, increasing the conducting time of the first switch in the current period and reducing the conducting time of the second switch in the current period based on the voltage ratio;
When the acquired voltage is smaller than the preset voltage, reducing the conduction time of the first switch in the current period and increasing the conduction time of the second switch in the current period based on the voltage ratio.
2. The motor throttle circuit of claim 1, wherein the first switch is a first mos transistor and the first switch is a second mos transistor;
The grid electrode of the first mos tube is connected with a first pulse output end of the pulse controller, the grid electrode of the second mos tube is connected with a second pulse output end of the pulse controller, and the drain electrode of the second mos tube is connected with a detection end of the pulse controller;
The motor speed regulating circuit is also provided with a series voltage division circuit comprising a first resistor and a second resistor; one end of the series voltage division circuit is connected with the drain electrode of the second mos tube, and the other end of the series voltage division circuit is connected with the source electrode of the second mos tube; the detection end is connected with a node at the joint of the first resistor and the second resistor and used for detecting the voltage at two ends of the second resistor.
3. The motor speed regulation circuit of claim 2 wherein the first commutation module comprises a first commutation bridge and the second commutation module comprises a second commutation bridge;
the first rectifier bridge comprises a diode D1, a diode D2, a diode D3, and a diode D4; the anode of the diode D1 is connected with the cathode of the diode D2 and the input end of the motor respectively, the cathode of the diode D3 is connected with the anode of the diode D4 and the output end of the motor respectively, the cathode of the diode D1 is connected with the cathode of the diode D4 and the drain of the first mos tube respectively, and the anode of the diode D2 is connected with the anode of the diode D3 and the source of the first mos tube respectively;
The second rectifier bridge comprises a diode D5, a diode D6, a diode D7, and a diode D8; the anode of the diode D5 is connected with the cathode of the diode D6 and the output end of the motor respectively, the cathode of the diode D7 is connected with the anode of the diode D8 and the zero line respectively, and the cathode of the diode D5 is connected with the cathode of the diode D8 and the drain of the second mos tube respectively; the anode of the diode D6 is connected to the anode of the diode D7 and the source of the second mos transistor, respectively.
4. the motor speed regulation circuit of claim 2 wherein the gate of the first mos transistor is connected to the first pulse output terminal through an opto-coupler.
5. a motor speed regulation method, which adopts the motor speed regulation circuit of any one of claims 1 to 4, characterized in that the motor speed regulation method comprises the following steps:
when the first switch is turned on and the second switch is turned off, the pulse controller acquires the voltage of the detection end;
determining whether the acquired voltage is equal to a preset voltage;
When the acquired voltage is not equal to a preset voltage, adjusting the on-time of the first switch and the on-time of the second switch in the current period based on the acquired voltage and the preset voltage.
6. The method for regulating speed of a motor according to claim 5, wherein the step of adjusting the on-time of the first switch and the on-time of the second switch in the current period based on the acquired voltage and a preset voltage comprises:
Calculating the voltage difference between the acquired voltage and the preset voltage;
Calculating a voltage ratio between the voltage difference and the preset voltage;
And when the acquired voltage is greater than the preset voltage, increasing the conduction time of the first switch in the current period and reducing the conduction time of the second switch in the current period based on the voltage ratio.
7. A method of regulating speed of a motor as claimed in claim 6, wherein said step of calculating a voltage ratio between said voltage difference and said preset voltage is followed by further comprising:
When the acquired voltage is smaller than the preset voltage, reducing the conduction time of the first switch in the current period and increasing the conduction time of the second switch in the current period based on the voltage ratio.
8. A method for regulating a speed of a motor according to any one of claims 5 to 7, wherein when the first switch is a first mos transistor and the first switch is a second mos transistor, the step of obtaining a voltage at a detection terminal of the pulse controller when the first switch is turned on and the second switch is turned off comprises:
and when the first mos tube is conducted and the second mos tube is cut off, delaying a preset time interval to obtain the voltage of the detection end.
9. a motor speed control device, characterized in that, the motor speed control circuit of any one of claims 1 to 4 is used, the motor speed control device comprises: a memory and a motor speed regulation program stored on the memory and operable on the pulse controller, wherein:
The motor speed regulation program when executed by the pulse controller implements the steps of the motor speed regulation method according to any one of claims 5 to 8.
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| US9698694B2 (en) * | 2014-01-10 | 2017-07-04 | Astec International Limited | Control circuits and methods for regulating output voltages based on adjustable references voltages |
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| CN101382814A (en) * | 2007-09-07 | 2009-03-11 | 苏州三星电子有限公司 | PWM controlled RC step-down power supply circuit based on feedback |
| CN102202449A (en) * | 2011-06-30 | 2011-09-28 | 杭州士兰微电子股份有限公司 | LED driving control circuit and method |
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