A connection circuit for a brushless motor compatible with a brushed motor main control board

Abstract

The present invention discloses a connection circuit for a brushless motor compatible with a brushed motor main control board, comprising: a control chip U2, a rectifier circuit, a sampling circuit, a stall simulation circuit and a drive feedback circuit. The input end of the rectifier circuit is electrically connected to the output terminal J1 of the main control board. The rectifier circuit rectifies the voltage provided by the main control board and outputs a voltage VM. The voltage VM powers the drive feedback circuit. The sampling circuit collects the voltage signal of the main control board and feeds it back to the control chip U2. The control chip U2 determines the direction and magnitude of the current voltage of the main control board according to the sampling signal, and outputs a control signal to the drive feedback circuit. The drive feedback circuit drives the brushless motor according to the control signal and feeds back the status signal of the brushless motor to the control chip U2. The stall simulation circuit is electrically connected to the control chip U2 and a host computer. If the motor is stalled, the control chip U2 controls the stall simulation circuit according to the status signal to transmit a corresponding electrical signal to the host computer, so that the host computer knows that the motor has reached a limit point.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, in particular to a connection circuit for a brushless motor compatible with a brushed motor main control board. Background Art

[0002] Compared to brushless DC motors, brushed DC motors in consumer electronics suffer from higher noise, more complex reduction mechanisms, higher stall currents, higher electromagnetic interference, lower precision, and a lack of soft start / stop functionality. This has led many manufacturers to consider replacing brushless DC motors with brushless DC motors. However, brushless DC motors come with built-in electronic control driver boards (typically with three to six wiring harnesses), which are incompatible with the two-wire power supply of brushed DC motors. Switching to a brushless DC motor requires major changes to the electronic product's main control board circuitry and supporting software. Modifying the main control board circuitry involves complex changes to molds and materials, resulting in high costs and a significant pain point for the industry. Summary of the Invention

[0003] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a connection circuit for a brushless motor to be compatible with a brushed motor main control board.

[0004] According to an embodiment of the present invention, a connection circuit for a brushless motor compatible with a brushed motor main control board includes: a control chip U2, a rectifier circuit, a sampling circuit, a stall simulation circuit, and a drive feedback circuit. The input end of the rectifier circuit is electrically connected to the output terminal J1 of the main control board. The rectifier circuit is used to rectify the voltage provided by the main control board and output a voltage VM. The voltage VM powers the drive feedback circuit. The sampling circuit is used to collect the voltage signal of the main control board and feed it back to the control chip U2. The control chip U2 determines the direction and magnitude of the current voltage of the main control board based on the sampling signal, and then outputs a control signal to the drive feedback circuit. The drive feedback circuit drives the brushless motor at a corresponding speed and direction based on the control signal and simultaneously feeds back a status signal of the brushless motor to the control chip U2. One end of the stall simulation circuit is electrically connected to the control chip U2, and the other end of the stall simulation circuit is electrically connected to a host computer. When a stall occurs, the control chip U2 controls the stall simulation circuit to transmit a corresponding electrical signal to the host computer based on changes in the status signal, so that the host computer can detect that the motor has reached a limit point.

[0005] The connection circuit of the brushless motor compatible with the brush motor main control board according to the embodiment of the present invention has at least the following beneficial effects: the voltage output by the main control board is rectified by the rectifier circuit to form the power supply voltage VM required by the brushless motor, and the voltage VM also powers the drive feedback circuit. The control chip U2 inputs a control signal to the drive feedback circuit, and the drive feedback circuit outputs the drive current required by the brushless motor to generate a rotating magnetic field according to the control signal; at the same time, the sampling circuit samples the current voltage output by the main control board to obtain a sampling signal and feeds the sampling signal back to the control chip U2. The control chip U2 determines the direction and size of the current voltage of the main control board according to the sampling signal (that is, identifies the rotation direction of the original brush motor), and the control chip U2 determines the direction and size of the current voltage of the main control board according to the sampling signal (that is, identifies the rotation direction of the original brush motor), and the control chip U2 determines the direction and size of the current voltage of the main control board according to the sampling signal. The magnitude of the pre-voltage controls the output of a corresponding control signal to the drive feedback circuit. When the motor reaches the limit point during rotation and becomes stalled, the drive feedback circuit feeds back the motor-side status signal (such as a level change signal) to the control chip U2. The control chip U2 determines that the current is a stall signal based on the level change signal, and then controls the stall simulation circuit to transmit a certain level signal to the host computer (for example, the stall simulation circuit is turned on and transmits a large current to the host computer, or the stall simulation circuit inputs a changing electrical signal to the host computer to remind the host computer that it is currently in a stall state). This simulates the characteristic of the original DC brush motor that the current increases when it stalls, allowing the original host computer to detect that the motor has reached the limit point through current changes. Without changing the original main control board, and without involving complex changes in materials, molds, etc., users can quickly achieve compatibility between DC brush and DC brushless motors without changing the original main control circuit and wiring, effectively saving costs and facilitating application. Moreover, after switching to a brushless DC motor, its electromagnetic interference is significantly reduced, energy saving and efficiency are increased, and it has built-in over-temperature protection, which improves safety. Moreover, after sampling the brushless DC motor, the product's noise is significantly reduced, the start and stop are smooth, and the control is precise, which greatly improves the user experience.

[0006] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings;

[0008] Figure 1 This is the schematic diagram of the connection circuit of the brushless motor compatible with the brush motor main control board. DETAILED DESCRIPTION

[0009] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it should not be understood as a limitation on the scope of protection of the present invention.

[0010] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0011] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0012] Reference Figure 1 The present invention provides a connection circuit for a brushless motor compatible with a brushed motor main control board, comprising: a control chip U2, a rectifier circuit 10, a sampling circuit 20, a stall simulation circuit 30, and a drive feedback circuit 40. The input end of the rectifier circuit 10 is electrically connected to the output terminal J1 of the main control board. The rectifier circuit 10 is used to rectify the voltage provided by the main control board and output a voltage VM. The voltage VM is used to power the drive feedback circuit 40. The sampling circuit 20 is used to collect the voltage signal of the main control board and feed it back to the control chip U2. The control chip U2 determines the current voltage of the main control board based on the sampling signal. direction and magnitude, and then outputs a control signal to the drive feedback circuit 40. The drive feedback circuit 40 drives the brushless motor M1 at a corresponding speed and direction according to the control signal and at the same time feeds back the status signal of the brushless motor M1 to the control chip U2; one end of the stall simulation circuit 30 is electrically connected to the control chip U2, and the other end of the stall simulation circuit 30 is electrically connected to the host computer. When a stall occurs, the control chip U2 controls the stall simulation circuit 30 to transmit a corresponding electrical signal to the host computer according to the change of the status signal, so that the host computer can detect that the motor has reached the limit point.

[0013] That is, the voltage output by the main control board is rectified by the rectifier circuit 10 to form the power supply voltage VM required by the brushless motor M1. The voltage VM also powers the drive feedback circuit 40. The control chip U2 inputs a control signal to the drive feedback circuit 40. The drive feedback circuit 40 outputs the drive current required by the brushless motor M1 to generate a rotating magnetic field according to the control signal. At the same time, the sampling circuit 20 samples the current voltage output by the main control board to obtain a sampling signal and feeds the sampling signal back to the control chip U2. The control chip U2 determines the direction and magnitude of the current voltage of the main control board according to the sampling signal (that is, identifies the rotation direction of the original brush motor), and the control chip U2 controls the output of the corresponding control signal according to the magnitude of the current voltage. To the drive feedback circuit 40; when the motor reaches the limit point during rotation and becomes stalled, the drive feedback circuit 40 will feed back the motor end status signal (such as a level change signal) to the control chip U2. The control chip U2 determines that the current is a stall signal based on the level change signal, and then controls the stall simulation circuit 30 to transmit a certain level signal to the host computer (for example, the stall simulation circuit 30 is turned on and transmits a large current to the host computer, or the stall simulation circuit 30 inputs a changing electrical signal to the host computer to remind the host computer that it is currently in a stall state). This simulates the characteristic of the original DC brush motor that the current increases when it is stalled, allowing the original host computer to detect that the motor has reached the limit point by changing the current. There is no need to change the original main control board, and there is no need to involve complex changes in materials, molds, etc., allowing users to quickly achieve compatibility between DC brush and DC brushless motors M1 without changing the original main control circuit and wiring, effectively saving costs and facilitating application. Moreover, after switching to the brushless DC motor M1, its electromagnetic interference is significantly reduced, energy saving and efficiency are increased, and it has built-in over-temperature protection, which improves safety. Moreover, after sampling the brushless DC motor M1, the product's noise is significantly reduced, the start and stop are smooth, and the control is precise, which greatly improves the user experience.

[0014] like Figure 1 Terminal J1 is the output terminal of the main control board and is the connector of the original DC brush motor. The rectifier circuit 10 includes an overcurrent fuse F1, a rectifier bridge B1, a surge voltage absorption diode TVS1, and filter capacitors C1 and C2. The control chip U2 is a small CPU ( Figure 1 The sampled one is an 8-bit MCU).

[0015] In some embodiments, a step-down circuit 11 is further included, which is electrically connected to the output terminal of the rectifier circuit 10 and is used to convert the voltage VM into a voltage VDD, which serves as the operating voltage of the control chip U2. Figure 1 The step-down circuit 11 includes a voltage stabilizer U1, a capacitor C3 and a capacitor C4. The capacitors C3 and C4 are filter capacitors for the voltage Vdd.

[0016] In some embodiments, the sampling circuit 20 includes a resistor R1, a resistor R2, and a diode D1. The positive end of the diode D1 is electrically connected to the output terminal J1 of the main control board. The negative end of the diode D1 is electrically connected to one end of the resistor R2 and the sampling identification terminal of the control chip U2 after being connected in series with the resistor R1. The other end of the resistor R2 is grounded. The positive end of the diode D1 samples the current voltage of the main control board from the output terminal J1, and obtains a sampling signal through voltage division by the resistors R1 and R2. The sampling signal is given to the control chip U2. The control chip U2 determines the direction and magnitude of the current voltage of the main control board based on the sampling signal, that is, identifies the rotation direction of the original brushless motor. The control chip U2 outputs a corresponding PWM signal to the drive feedback circuit 40 through the speed direction control terminal RB5 based on the magnitude and direction of the current voltage. The drive feedback circuit 40 outputs the drive current required by the brushless motor M1 to generate a rotating magnetic field according to the PWM signal. The diode D1 plays a role in reverse voltage protection.

[0017] In some embodiments, the sampling circuit 20 includes a capacitor C8 connected in parallel with the resistor R2 , and the capacitor C8 functions as a filter.

[0018] In some embodiments, the drive feedback circuit 40 includes a drive chip U3, a resistor R3, and a resistor R4. The resistors R3 and R4 are pull-up resistors when the drive chip U3 is working; one end of the resistor R3 and one end of the resistor R4 are respectively electrically connected to the output end of the step-down circuit 11, and the other end of the resistor R3 is respectively electrically connected to the speed direction control end RB5 of the control chip U2 and the signal end PWM of the drive chip U3. The speed direction control end RB5 of the control chip U2 inputs a PWM signal to the drive chip U3. The other end of the resistor R4 is respectively electrically connected to the feedback output end FG of the drive chip U3 and the motor state feedback end RB3 of the control chip U2. The output end of the drive chip U3 is electrically connected to the brushless motor M1. While driving the brushless motor M1, the driver chip U3 feeds back a level change signal (state signal) of the brushless motor M1 to the motor state feedback end RB3 of the control chip U2. The control chip U2 performs simulated overcurrent control on the stall simulation circuit 30 according to the state signal of the brushless motor M1.

[0019] In some embodiments, the stall simulation circuit 30 includes a resistor R5, a resistor R6 and a switch tube Q1. Figure 1As shown, the switch Q1 is an N-channel MOS switch, resistor R5 is the gate resistor of the switch Q1, and resistor R6 is a low-power discharge resistor. One end of resistor R6 is electrically connected to the output terminal of the rectifier circuit 10, and the other end of resistor R6 is electrically connected to the positive terminal of the switch Q1. The negative terminal of the switch Q1 is grounded. The control terminal of the switch Q1 is electrically connected to the analog overcurrent control terminal RB4 of the control chip U2 via the series resistor R5. The control chip U2 performs analog overcurrent control on the stall simulation circuit 30 based on the status signal of the brushless motor M1. For example, when the brushless motor M1 is stalled, the control chip U2 determines that it is a stall signal based on the level change signal fed back by the driver chip U3. It then controls the stall simulation circuit 30 to conduct, transmitting a large current to the host computer to alert the host computer of the current stall state. This simulates the characteristic of the original DC brush motor that the current increases when the motor is stalled, allowing the original host computer to detect that the motor has reached the limit point through the current change.

[0020] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above preferred embodiments can be freely combined and superimposed.

[0021] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. All equivalent structural transformations made based on the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A connection circuit for a brushless motor compatible with a brushed motor main control board, characterized in that: include: A control chip U2, a rectifier circuit (10), a sampling circuit (20), a stall simulation circuit (30) and a drive feedback circuit (40), wherein the input end of the rectifier circuit (10) is electrically connected to the output terminal J1 of the main control board, the rectifier circuit (10) is used to rectify the voltage provided by the main control board and output a voltage VM, the voltage VM is used to power the drive feedback circuit (40), the sampling circuit (20) is used to collect the voltage signal of the main control board and feed it back to the control chip U2, the control chip U2 determines the direction and magnitude of the current voltage of the main control board according to the sampling signal, and then outputs the control signal. The signal is given to the driving feedback circuit (40), and the driving feedback circuit (40) drives the brushless motor M1 at a corresponding speed and direction according to the control signal and simultaneously feeds back the status signal of the brushless motor M1 to the control chip U2; one end of the stall simulation circuit (30) is electrically connected to the control chip U2, and the other end of the stall simulation circuit (30) is electrically connected to the host computer. When stall occurs, the control chip U2 controls the stall simulation circuit (30) to transmit a corresponding electrical signal to the host computer according to the change of the status signal, so that the host computer can detect that the motor has run to the limit point.

2. The connection circuit of the brushless motor compatible with the brushed motor main control board according to claim 1, characterized in that: It also includes a step-down circuit (11), which is electrically connected to the output end of the rectifier circuit (10) and is used to convert the voltage VM into a voltage VDD, and the voltage VDD serves as the operating voltage of the control chip U2.

3. The connection circuit of the brushless motor compatible with the brushed motor main control board according to claim 2, characterized in that: The sampling circuit (20) includes a resistor R1, a resistor R2 and a diode D1. The positive end of the diode D1 is electrically connected to the output terminal J1 of the main control board. The negative end of the diode D1 is electrically connected to one end of the resistor R2 and the sampling identification end of the control chip U2 after being connected in series with the resistor R1. The other end of the resistor R2 is grounded. The positive end of the diode D1 samples the current voltage of the main control board from the output terminal J1, and obtains a sampling signal through the resistor R1 and the resistor R2 voltage divider. The sampling signal is given to the control chip U2. The control chip U2 determines the direction and magnitude of the current voltage of the main control board by identifying the sampling signal. The diode D1 plays a role in reverse voltage protection.

4. The connection circuit of the brushless motor compatible with the brushed motor main control board according to claim 3, characterized in that: The sampling circuit (20) includes a capacitor C8, which is connected in parallel with the resistor R2 and plays a filtering role.

5. The connection circuit of the brushless motor compatible with the brushed motor main control board according to claim 2, characterized in that: The driving feedback circuit (40) includes a driving chip U3, a resistor R3, and a resistor R4. One end of the resistor R3 and one end of the resistor R4 are electrically connected to the output end of the step-down circuit (11), respectively. The other end of the resistor R3 is electrically connected to the speed direction control end RB5 of the control chip U2 and the signal end PWM of the driving chip U3, respectively. The speed direction control end RB5 of the control chip U2 inputs a PWM signal to the driving chip U3. The other end of the resistor R4 is electrically connected to the feedback output end FG of the driving chip U3 and the motor state feedback end RB3 of the control chip U2, respectively. The output end of the driving chip U3 is electrically connected to the brushless motor M1. The driving chip U3 drives the brushless motor M1 and feeds back the state signal of the brushless motor M1 to the control chip U2.

6. The connection circuit of the brushless motor compatible with the brushed motor main control board according to claim 1, characterized in that: The stall simulation circuit (30) includes a resistor R5, a resistor R6, and a switch tube Q1, one end of the resistor R6 is electrically connected to the output end of the rectifier circuit (10), the other end of the resistor R6 is electrically connected to the positive end of the switch tube Q1, the negative end of the switch tube Q1 is grounded, and the control end of the switch tube Q1 is electrically connected to the analog overcurrent control end RB4 of the control chip U2 via the series resistor R5.

Images