Direct-current brushless motor single-wire control device

Abstract

A single-line control device for a direct-current brushless motor is suitable for being used between a controller and a pre-driving stage of the direct-current brushless motor and comprises a coding modulation unit, a transmission line and a demodulation decoding unit. Wherein the coding modulation unit is connected with the controller and is used for receiving a control signal from the controller and coding and modulating the control signal to generate a modulation signal; the transmission line is connected to the coding modulation unit and is used for transmitting the modulation signal to the demodulation decoding unit; the demodulation and decoding unit is connected to the transmission line and used for demodulating and decoding the received modulation signal to generate an original control signal and then transmitting the original control signal to the pre-driving stage.

Description

Technical Field

[0001] The invention relates to a single-line control device for a brushless DC motor. Background Art

[0002] Brushless DC Motor (BLDC) is an electric motor without brushes and commutators. It adjusts the stator current according to the position of the rotor permanent magnet to generate torque. It is called "brushless DC motor" because it can replace brushed DC motors in many applications.

[0003] The BLDC motor uses a controller to detect the position and speed changes of the rotor, and sends a commutation control signal to the motor in a timely manner to start the motor rotating. In other words, the direction of the current passing through the coil group is controlled by switching the DC power switch, and the torque is obtained to rotate the rotor. Traditionally, square wave drive is called BLDC, and sine wave drive is called permanent-magnet synchronous motor (PMSM). Common BLDCs include single-phase brushless DC motor (SBLDC) and three-phase brushless DC motor.

[0004] Generally, four wires are required between the drive controller, pre-drive stage and power stage of SBLDC to transmit control signals. Figure 1 FIG. 4 is a schematic diagram of a control signal between an existing SBLDC controller and a pre-driver stage, as shown in FIG. Figure 1 As shown, the left side shows that the controller 101 outputs four control signals, namely AH, AL, BH, and BL to the pre-driver stage 102, and then the pre-driver stage 102 converts the received control signals AH, AL, BH, and BL into S1, S2, S3, and S4 outputs for controlling the four transistors of the power stage 103; wherein M is the motor, PH1 and PH2 are the states of the motor M, and VA and VB represent the potentials of points A and B, respectively.

[0005] Similarly, six wires are required between the drive controller, pre-driver stage and power stage of the three-phase BLDC to transmit control signals. Figure 2 FIG. 1 is a schematic diagram of control signals between a controller and a pre-driver stage of an existing three-phase BLDC, as shown in FIG. Figure 2As shown, the left side shows that the controller 201 outputs six control signals, namely AH, AL, BH, BL, CH, and CL to the pre-driver stage 202, and then the pre-driver stage 202 converts the received control signals AH, AL, BH, BL, CH, and CL into S1, S2, S3, S4, S5, and S6 outputs for controlling the six transistors of the power stage 203; among them, M is the motor, and its pins are connected to three points A, B, and C respectively.

[0006] However, the number of pins used in the prior art is large and occupies the area of ​​the circuit board, so reducing the number of pins used will help further miniaturization of BLDC. Summary of the invention

[0007] The main purpose of the present invention is to provide a single-line control device for a brushless DC motor, which is suitable for use between a controller and a pre-driver stage of a brushless DC motor, so that a control signal can be transmitted between the controller and the pre-driver stage via a single transmission line.

[0008] In order to achieve the above-mentioned purpose, the present invention provides a single-line control device for a brushless DC motor, which is suitable for use between a controller and a pre-driver stage of a brushless DC motor, and includes a coding modulation unit, a transmission line, and a demodulation and decoding unit; wherein the coding modulation unit is connected to the controller to receive a control signal from the controller, and encodes and modulates the control signal to generate a modulation signal; the transmission line is connected to the coding modulation unit to transmit the modulation signal to the demodulation and decoding unit; the demodulation and decoding unit is connected to the transmission line to demodulate and decode the received modulation signal to generate an original control signal, and then transmit it to the pre-driver stage.

[0009] In a preferred embodiment, the brushless DC motor is a single-phase brushless DC motor, and there are four control signals, namely AH, AL, BH, and BL.

[0010] In a preferred embodiment, when the control signals [AH, AL, BH, BL] = [0, 0, 0, 0], the single-phase DC brushless motor is in the PH_OFF state, and the modulation signal output by the encoding modulation unit is 0; when the control signals [AH, AL, BH, BL] = [1, 0, 0, X], the single-phase DC brushless motor is in the PH1 state, and the modulation signal output by the encoding modulation unit is MBL; when the control signals [AH, AL, BH, BL] = [0, X, 1, 0], the single-phase DC brushless motor is in the PH2 state, and the modulation signal output by the encoding modulation unit is MAL; where X indicates that the signal levels 0 and 1 are indistinguishable, and PH1, PH2, and PH_OFF respectively represent three states of the single-phase DC brushless motor; MAL and MBL are the modulated AL and BL signals respectively.

[0011] In a preferred embodiment, the modulation function of AL is MAL = 0.3xAL + 0.7xVDD, and the modulation function of BL is MBL = 0.3xBL + 0.2xVDD, where VDD is the voltage source.

[0012] In a preferred embodiment, the demodulation and decoding unit further includes a comparison module and a combinational logic circuit; the comparison module performs an operation on the modulation signal through a comparison program to generate four signals, namely PH1HL, PH2, PH2HL, and PHOFF, and the combinational logic circuit then maps the four signals PH1HL, PH2, PH2HL, and PHOFF into the four original control signals AL, AH, BL, and BH.

[0013] In a preferred embodiment, the operation of the comparison program is as follows:

[0014] If the modulation signal > VDDx85%, then PH2HL = 1, otherwise PH2HL = 0;

[0015] If the modulation signal > VDDx60%, then PH2 = 1, otherwise PH2 = 0;

[0016] If the modulation signal < VDDx15%, then PHOFF = 1, otherwise PHOFF = 0;

[0017] If the modulation signal > VDDx35%, then PH1HL = 1, otherwise PH1HL = 0.

[0018] In a preferred embodiment, the combinational logic circuit operates as follows:

[0019] AL = PH2HL ∧ BH;

[0020]

[0021]

[0022] BL=AH∧PH1HL;

[0023] Among them, ∧ is the logical operation symbol and, ∨ is the logical operation symbol or, The logical operator is not.

[0024] In a preferred embodiment, the brushless DC motor is a three-phase brushless DC motor, and the control signals are six, namely AH, AL, BH, BL, CH, and CL.

[0025] In a preferred embodiment, when the control signal [AH, AL, BH, BL, CH, CL] = [1, 0, 0, 0, 0, X], the three-phase DC brushless motor is in the PH1 state, the modulation signal output by the code modulation unit is MCL, and the basic voltage is 0V; when [AH, AL, BH, BL, CH, CL] = [1, 0, 0, X, 0, 0], the three-phase DC brushless motor is in the PH2 state, the modulation signal output by the code modulation unit is MCL, and the basic voltage is 0V. The modulation signal output is MBL, and the basic voltage is VDDx0.8; when [AH, AL, BH, BL, CH, CL] = [0, 0, 0, X, 1, 0], the three-phase DC brushless motor is in PH3 state, the modulation signal output by the encoding modulation unit is MBL, and the basic voltage is VDDx0.5; when [AH, AL, BH, BL, CH, CL] = [0, X, 0, 0, 1, 0], the three-phase DC The brushless motor is in PH4 state, the modulation signal output by the code modulation unit is MAL, and the basic voltage is VDDx0.8; when [AH, AL, BH, BL, CH, CL] = [0, X, 1, 0, 0, 0], the three-phase DC brushless motor is in PH5 state, the modulation signal output by the code modulation unit is MAL, and the basic voltage is VDDx0.5; when [AH, AL, BH, BL, CH, CL] = [ 0, 0, 1, 0, 0, X], the three-phase DC brushless motor is in PH6 state, the modulation signal output by the encoding modulation unit is MCL, and the basic voltage is VDDx0.8; wherein X represents that there is no difference between signal levels 0 and 1, PH1, PH2, PH3, PH4, PH5, and PH6 respectively represent six states of the three-phase DC brushless motor, the basic voltage is the voltage value added to the modulation signal before the modulation is completed, and VDD is the voltage source.

[0026] In a preferred embodiment, the modulation functions of AL, BL, and CL are MAL=0.2xAL+the basic voltage, MBL=0.2xBL+the basic voltage, and MCL=0.2xCL+the basic voltage.

[0027] In a preferred embodiment, the demodulation and decoding unit further includes a comparison module and a combinational logic circuit; the comparison module performs an operation on the modulation signal through a comparison program to generate five signals, namely PH1, PH1HL, PH246, PH246HL, and PH35. Then, after the PH246 signal passes through an edge detector and the PH1 signal passes through a state counter, five signals, namely PH2, PH3, PH4, PH5, and PH6, are output. Moreover, the combinational logic circuit maps the ten signals, namely PH1, PH1HL, PH246, PH246HL, PH35, PH2, PH3, PH4, PH5, and PH6, into six original control signals, namely AL, AH, BL, BH, CH, and CL.

[0028] In a preferred embodiment, the operation of the comparison program is as follows:

[0029] If the modulation signal > VDDx95%, then PH246HL = 1; otherwise, PH246HL = 0;

[0030] If the modulation signal > VDDx60%, then PH35HL = 1; otherwise, PH35HL = 0;

[0031] If the modulation signal > VDDx10%, then PH1HL = 1; otherwise, PH1HL = 0;

[0032] If the modulation signal > VDDx75%, then PH246 = 1; otherwise, PH246 = 0;

[0033] If the modulation signal < VDDx30%, then PH1 = 1; otherwise, PH1 = 0.

[0034] In a preferred embodiment, the operation of the combinational logic circuit is as follows:

[0035] AH = PH1 ∨ PH2;

[0036] BH = PH5 ∨ PH6;

[0037] CH = PH3 ∨ PH4;

[0038] AL = (PH246HL ∧ PH4) ∨ (PH35HL ∧ PH5);

[0039] BL = (PH246HL ∧ PH2) ∨ (PH35HL ∧ PH3);

[0040] CL = (PH246HL ∧ PH6) ∨ (PH1HL ∧ PH1);

[0041] Among them, ∧ is the logical operation symbol AND, and ∨ is the logical operation symbol OR.

[0042] In a preferred embodiment, the encoding modulation unit is integrated into the controller of the DC brushless motor; and the demodulation and decoding unit is integrated into the pre-driver stage of the DC brushless motor; or the demodulation and decoding unit is integrated into the pre-driver stage and power stage of the DC brushless motor.

[0043] The effect of the present invention lies in that the single-wire control device for a brushless DC motor of the present invention can effectively reduce the design that originally requires 4-6 transmission lines to transmit the control signal between the controller and the pre-driver stage to a modulation signal that can be transmitted by a single transmission line through a modulation design; furthermore, the single-wire control device for a brushless DC motor can be further integrated into the controller and the pre-driver stage to achieve the purpose of reducing the occupied circuit board area. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 FIG. 4 is a schematic diagram showing control signals between a conventional SBLDC controller and a pre-driver stage.

[0045] Figure 2 FIG. 4 is a schematic diagram showing control signals between a conventional three-phase BLDC controller and a pre-driver stage.

[0046] Figure 3 The structure block diagram of the single-line control device for a brushless DC motor of the present invention is shown.

[0047] Figure 4 It is a schematic structural diagram of the single-line control device for a brushless DC motor of the present invention when it is applied to a single-phase brushless DC motor.

[0048] Figure 5A Shown is a schematic diagram of the circuit structure of the power stage of the single-phase brushless DC motor of the present invention.

[0049] Figure 5B FIG. 1 is a schematic diagram showing a phase waveform of a power stage of a single-phase brushless DC motor according to the present invention.

[0050] Figure 5C The figure shows a truth table between the control signals AL, AL, BH, BL and the drive signals S1, S2, S3, S4 of the power stage of the single-phase brushless DC motor of the present invention.

[0051] Figure 6 FIG. 1 is a schematic diagram of a first embodiment of a code modulation unit of a single-wire control device for a brushless DC motor according to the present invention.

[0052] Figure 7 The corresponding Figure 6 Waveform diagram of each signal.

[0053] Figure 8FIG. 1 is a schematic diagram of a first embodiment of a demodulation and decoding unit of a single-wire control device for a brushless DC motor according to the present invention.

[0054] Fig. 9 It is a schematic structural diagram of the single-line control device for a brushless DC motor of the present invention when it is applied to a three-phase brushless DC motor.

[0055] Fig. 10A The figure shows the current flow structure schematic diagram of the power stage of a three-phase brushless DC motor under six states.

[0056] Fig. 10B Shown is a schematic diagram of the phase waveform of the power stage of a three-phase brushless DC motor.

[0057] Fig. 10C Shown is a true and false value table between control signals AL, AL, BH, BL, CH, CL and drive signals S1, S2, S3, S4, S5, S6 of the power stage of a single-phase brushless DC motor.

[0058] Fig.11 FIG. 1 is a schematic diagram of a second embodiment of a code modulation unit of a single-wire control device for a brushless DC motor according to the present invention.

[0059] Fig.12 The corresponding Fig.11 Waveform diagram of each signal.

[0060] Fig.13 FIG. 1 is a schematic diagram of a second embodiment of a demodulation and decoding unit of a single-wire control device for a brushless DC motor according to the present invention.

[0061] Description of reference numerals:

[0062] 101-controller, 102-pre-driver stage, 103-power stage, 201-controller, 202-pre-driver stage, 203-power stage, 301-controller, 3011-coding modulation unit, 3012-transmission line (SWP), 3021-demodulation decoding unit, 302-pre-driver stage, 401-controller, 4011-coding modulation unit, 4012-transmission line (SWP), 4021-demodulation decoding unit Modulation and decoding unit, 402-pre-driving stage, 8021A-comparison module, 8021B-combinatorial logic circuit, 901-controller, 9011-coding modulation unit, 9012-transmission line (SWP), 9021-demodulation and decoding unit, 902-pre-driving stage, 13021A-comparison module, 13021B-combinatorial logic circuit, 13021C-edge detector, 13021D-state counter. DETAILED DESCRIPTION

[0063] The following is a more detailed description of the embodiments of the present invention with the help of drawings and component symbols, so that those skilled in the art can implement the invention accordingly after reading the specification.

[0064] Figure 3 The structure block diagram of the single-line control device for a brushless DC motor of the present invention is shown in FIG. Figure 3 As shown, a single-wire control device for a brushless DC motor of the present invention is suitable for use between a controller 301 and a pre-driver stage 302 of a brushless DC motor, and includes an encoding modulation unit 3011, a transmission wire 3012, and a demodulation decoding unit 3021; ​​wherein the encoding modulation unit 3011 is connected to the controller 301 to receive a control signal from the controller 301, and encodes and modulates the control signal to generate a modulation signal; the transmission wire (denoted as SWP in the figure) 3012 is connected to the encoding modulation unit 3011 to transmit the modulation signal to the demodulation decoding unit 3021; ​​the demodulation decoding unit 3021 is connected to the transmission wire 3012 to demodulate and decode the received modulation signal to generate an original control signal, and then transmit it to the pre-driver stage 302.

[0065] It is worth noting that although Figure 3 In the embodiment, the code modulation unit 3011 is independent of the controller 301, but in a preferred embodiment, the code modulation unit 3011 can be integrated into the controller 301 of the brushless DC motor, as shown in the dotted box in the figure. Similarly, the demodulation and decoding unit 3021 can also be integrated into the pre-driving stage 302 of the brushless DC motor, or the demodulation and decoding unit 3021, the pre-driving stage 302 and the aforementioned Figure 1 The power stage 103. In this way, the area occupied by the circuit board can be further reduced, and thus reducing the number of pins used will contribute to further miniaturization of the BLDC.

[0066] Figure 4 FIG. 2 is a schematic diagram showing the structure of a single-line control device for a brushless DC motor of the present invention when it is applied to a single-phase brushless DC motor; Figure 4 As shown, there are four control signals, namely AH, AL, BH, and BL. Furthermore, the encoding modulation unit 4011 is integrated into the controller 401 of the brushless DC motor, and the demodulation decoding unit 4021 is also integrated into the pre-driving stage 402 of the brushless DC motor, and the modulated control signal is transmitted via the transmission line 4012.

[0067] refer to Figures 5A-5C , Figure 5AShown is a schematic diagram of the circuit structure of the power stage of a single-phase brushless DC motor; Figure 5B Shown is a schematic diagram of a phase waveform of a power stage of a single-phase brushless DC motor; Figure 5C The figure shows a truth table between control signals AL, AL, BH, BL and drive signals S1, S2, S3, S4 of the power stage of a single-phase brushless DC motor. Figure 5A The power stage of the single-phase brushless DC motor shown in FIG. 1 is in the state of PH2, and the flow direction of the current I is indicated by the arrow from V B Point flow to V A Point; PH1, PH2, and PH_OFF corresponding to V A Point, V B The waveform of the potential at point Figure 5B As shown; where V A =H, V B =L, the state is PH1; V A =L、V B =H, the state is PH2; V A =L、V B =L, the state is PH_OFF.

[0068] Since the control signal of the single-phase DC brushless motor must achieve only three states: PH1, PH2 and PH_OFF, the encoding modulation unit 4011 of the DC brushless motor single-line control device of the present invention must control the single-phase DC brushless motor to cycle between PH1, PH_OFF, PH2, and PH_OFF through encoding and modulation.

[0069] Figure 6 FIG. 1 is a schematic diagram of a first embodiment of a code modulation unit of a single-line control device for a brushless DC motor according to the present invention. Figure 6 The true and false value table on the left shows the corresponding relationship between input (AH, AL, BH, BL) and output (SWP, state); in other words, when the control signal [AH, AL, BH, BL] = [0, 0, 0, 0], the single-phase DC brushless motor is in the PH_OFF state, and the modulation signal output by the code modulation unit is 0; when the control signal [AH, AL, BH, BL] = [1, 0, 0, X], the single-phase DC brushless motor is in the PH1 state, and the modulation signal output by the code modulation unit is MBL; when the control signal [AH, AL, BH, BL] = [0, X, 1, 0], the single-phase DC brushless motor is in the PH2 state, and the modulation signal output by the code modulation unit is MAL; wherein X indicates that there is no difference between the signal levels 0 and 1, PH1, PH2, and PH_OFF respectively represent the three states of the single-phase DC brushless motor; MAL and MBL are the modulated AL and BL signals respectively.

[0070] Figure 6 The circuit diagram on the right shows that in a preferred embodiment, the control signal AL can be modulated to MAL=0.3xAL+0.7xVDD through a modulation function, where VDD is a voltage source. In other words, the AL signal is first reduced in amplitude and then voltage shifted to complete the modulation function. Similarly, the modulation function of BL is MBL=0.3xBL+0.2xVDD. It is worth noting that although the AL and BL signals are both reduced in amplitude, the base voltages of their voltage shifts are 0.7 and 0.2 respectively; the design of these parameters is sufficient to distinguish the control signals MAL and MBL after the reduction and modulation. Finally, the output signal is determined by the multiplexer MUX and outputted through a single transmission line SWP.

[0071] Figure 7 The corresponding Figure 6 The waveform diagram of each signal. Figure 7 As shown, the waveforms of the original control signals AH, AL, BH, BL are reduced in amplitude and modulated into the SWP signal waveforms; in particular, the AL and BL signals used for the output states PH1 and PH2 can be clearly distinguished and identified through voltage displacement.

[0072] Figure 8 FIG. 1 is a schematic diagram of a first embodiment of a demodulation and decoding unit of a single-line control device for a brushless DC motor according to the present invention, corresponding to FIG. Figure 6 Since the demodulation and decoding unit is used to demodulate and decode the modulated signal transmitted from the SWP transmission line into the original control signal, it can be regarded as an inverse function of the code modulation or a reverse engineering operation of the code modulation unit.

[0073] like Figure 8 As shown, the demodulation and decoding unit also includes a comparison module 8021A and a combinational logic circuit 8021B; wherein the comparison module 8021A operates the modulated signal through a comparison program to generate four signals such as PH1HL, PH2, PH2HL, and PHOFF, and the combinational logic circuit 8021B then maps the four signals such as PH1HL, PH2, PH2HL, and PHOFF into four original control signals such as AL, AH, BL, and BH.

[0074] In a preferred embodiment, the comparison procedure operates as follows:

[0075] If the modulation signal > VDDx85%, then PH2HL=1, otherwise PH2HL=0;

[0076] If the modulation signal > VDDx60%, PH2 = 1, otherwise PH2 = 0;

[0077] If the modulation signal < VDD x 15%, then PHOFF = 1; otherwise, PHOFF = 0.

[0078] If the modulation signal > VDD x 35%, then PH1HL = 1; otherwise, PH1HL = 0.

[0079] Similarly, the combinational logic circuit operates as follows:

[0080] AL = PH2HL ∧ BH;

[0081]

[0082]

[0083] BL = AH ∧ PH1HL;

[0084] where ∧ is the logical operation symbol AND, ∨ is the logical operation symbol OR, and are respectively the logical operation symbol NOT.

[0085] In other words, after being processed by the demodulation and decoding unit, the modulation signal (SWP) can be restored to the original control signals AH, AL, BH, and BL. That is, it is restored to the waveform as Figure 7 shown.

[0086] It should be noted that the various numerical values used in this embodiment are used to explain the feasibility of the present invention, but the present invention is not limited thereto; the selection of other appropriate numerical values is also within the scope of the present invention.

[0087] Fig. 9 The following shows the structural schematic diagram when the single-wire control device of the DC brushless motor of the present invention is applied to a three-phase DC brushless motor; as Fig. 9 shown, there are six control signals, namely AH, AL, BH, BL, CH, and CL. Furthermore, the encoding and modulation unit 9011 is integrated into the controller 901 of the three-phase DC brushless motor, and the demodulation and decoding unit 9021 is also integrated into the pre-drive stage 902 of the three-phase DC brushless motor, or the demodulation and decoding unit 9021, the pre-drive stage 902, and the foregoing Figure 2 power stage 203 are integrated together, and the modulated control signal is transmitted via the transmission line 9012.

[0088] Since the control signals of the three-phase DC brushless motor only need to achieve six states, namely PH1, PH2, PH3, PH4, PH5, and PH6, the encoding and modulation unit 9011 of the single-wire control device of the DC brushless motor of the present invention must reach the state of cycling alternately among PH1, PH2, PH3, PH4, PH5, and PH6 for controlling the three-phase DC brushless motor through encoding and modulation methods.

[0089] refer to Figures 10A-10C , Fig. 10A The following is a schematic diagram of the current flow structure of the three-phase brushless DC motor under six states of power level. Figure 2 A circuit of a power stage 203; Fig. 10B Shown is a schematic diagram of a phase waveform of a power stage of a three-phase brushless DC motor; Fig. 10C Shown is a truth table between control signals AL, AL, BH, BL, CH, CL and drive signals S1, S2, S3, S4, S5, S6 of the power stage of a single-phase brushless DC motor. Fig. 10A The directions of the current I of the power stage of the three-phase DC brushless motor shown are indicated by arrows 1, 2, 3, 4, 5, and 6, which correspond to Fig. 10B The potential waveforms of the three points A, B and C in six states: PH1, PH2, PH3, PH4, PH5 and PH6.

[0090] Fig.11 The diagram is a schematic diagram of a second embodiment of the code modulation unit of the single-line control device for a brushless DC motor of the present invention. Fig.11The true and false value table on the left shows the corresponding relationship between the input (AH, AL, BH, BL, CH, CL) and the output (state, SWP, basic voltage), wherein the basic voltage is a voltage value added to the modulation signal before the modulation is completed; in other words, according to the presentation of the true and false value table, when the control signal [AH, AL, BH, BL, CH, CL] = [1, 0, 0, 0, 0, X], the three-phase DC brushless motor is in the PH1 state, the modulation signal output by the encoder modulation unit is MCL, and The basic voltage is 0V; when [AH, AL, BH, BL, CH, CL] = [1, 0, 0, X, 0, 0], the three-phase DC brushless motor is in the PH2 state, the modulation signal output by the code modulation unit is MBL, and the basic voltage is VDDx0.8; when [AH, AL, BH, BL, CH, CL] = [0, 0, 0, X, 1, 0], the three-phase DC brushless motor is in the PH3 state, the modulation signal output by the code modulation unit is MBL, and the basic voltage is VDDx0.8. The base voltage is VDDx0.5; when [AH, AL, BH, BL, CH, CL] = [0, X, 0, 0, 1, 0], the three-phase DC brushless motor is in the PH4 state, the modulation signal output by the code modulation unit is MAL, and the base voltage is VDDx0.8; when [AH, AL, BH, BL, CH, CL] = [0, X, 1, 0, 0, 0], the three-phase DC brushless motor is in the PH5 state, the modulation signal output by the code modulation unit is MAL , and the basic voltage is VDDx0.5; when [AH, AL, BH, BL, CH, CL] = [0, 0, 1, 0, 0, X], the three-phase DC brushless motor is in PH6 state, the modulation signal output by the code modulation unit is MCL, and the basic voltage is VDDx0.8; wherein X represents that there is no difference between signal levels 0 and 1, PH1, PH2, PH3, PH4, PH5, and PH6 respectively represent six states of the three-phase DC brushless motor, wherein VDD is a voltage source.

[0091] Fig.11The circuit diagram on the right shows that in a preferred embodiment, the control signal AL can be modulated to MAL=0.2xAL+base voltage through a modulation function. In other words, the AL signal is first reduced in amplitude and then voltage shifted to complete the modulation function. Similarly, the modulation functions of BL and CL are MBL=0.2xBL+base voltage and MCL=0.2xCL+base voltage, respectively. It is worth noting that although the AL, BL, and CL signals are all reduced in amplitude, the base voltages of the voltage shifts of the three are 0.8VDD, 0.5VDD, and 0V, respectively; the design of these parameters is sufficient to distinguish the control signals MAL, MBL, and MCL after the reduction and modulation. Therefore, the output signal is first determined by the multiplexer MUX, and then reduced in amplitude and modulated to become the modulated control signal, which is finally output through a single transmission line SWP.

[0092] Fig.12 The corresponding Fig.11 The waveform diagram of each signal. Fig.12 As shown, the waveforms of the original control signals AH, AL, BH, BL, CH, and CL are reduced in amplitude and modulated to form the SWP signal waveforms.

[0093] Fig.13 FIG. 1 is a schematic diagram of a second embodiment of a demodulation and decoding unit of a single-line control device for a brushless DC motor according to the present invention, corresponding to FIG. Fig.11 As described in the first embodiment, the demodulation and decoding unit has the function of demodulating and decoding the modulated signal transmitted from the SWP transmission line into the original control signal, so it can be regarded as the inverse function of the code modulation, or the reverse engineering operation of the code modulation unit.

[0094] like Fig.13 As shown, the demodulation and decoding unit also includes a comparison module 13021A and a combinational logic circuit 13021B; the comparison module 13021A performs a comparison operation on the modulated signal to generate five signals, namely PH1, PH1HL, PH246, PH246HL, and PH35, and then the PH246 signal passes through an edge detector 13021C and the PH1 signal passes through a state counter 13021D, and then outputs five signals, namely PH2, PH3, PH4, PH5, and PH6. In addition, the combinational logic circuit then images the ten signals, namely PH1, PH1HL, PH246, PH246HL, PH35, PH2, PH3, PH4, PH5, and PH6, into six original control signals, namely AL, AH, BL, BH, CH, and CL.

[0095] In a preferred embodiment, the comparison procedure operates as follows:

[0096] If the modulation signal > VDD x 95%, then PH246HL = 1; otherwise, PH246HL = 0;

[0097] If the modulation signal > VDD x 60%, then PH35HL = 1; otherwise, PH35HL = 0;

[0098] If the modulation signal > VDD x 10%, then PH1HL = 1; otherwise, PH1HL = 0;

[0099] If the modulation signal > VDD x 75%, then PH246 = 1; otherwise, PH246 = 0;

[0100] If the modulation signal < VDD x 30%, then PH1 = 1; otherwise, PH1 = 0.

[0101] Similarly, the combinational logic circuit operates as follows:

[0102] AH = PH1 ∨ PH2;

[0103] BH = PH5 ∨ PH6;

[0104] CH = PH3 ∨ PH4;

[0105] AL = (PH246HL ∧ PH4) ∨ (PH35HL ∧ PH5);

[0106] BL = (PH246HL ∧ PH2) ∨ (PH35HL ∧ PH3);

[0107] CL = (PH246HL ∧ PH6) ∨ (PH1HL ∧ PH1);

[0108] Wherein, ∧ is the logical operation symbol AND, and ∨ is the logical operation symbol OR.

[0109] In other words, after being processed by the demodulation and decoding unit, the modulation signal (SWP) can be restored to the original control signals AH, AL, BH, BL, CH, and CL, that is, restored to the waveform as shown in Fig.12 the figure.

[0110] It should be noted that the various numerical values used in this embodiment are used to explain the feasibility of the present invention, but the present invention is not limited thereto; the selection of other appropriate numerical values is also within the scope of the present invention.

[0111] In summary, the single-wire control device for a brushless DC motor of the present invention can effectively reduce the design that originally required 4-6 transmission lines to transmit the control signal between the controller and the pre-driver stage to a modulation signal that can be transmitted by a single transmission line through a modulation design; furthermore, the single-wire control device for a brushless DC motor can be further integrated into the controller and the pre-driver stage to achieve the purpose of reducing the occupied circuit board area.

[0112] The above description is only used to explain the preferred embodiments of the present invention, and is not intended to limit the present invention in any form. Therefore, any modifications or changes made to the present invention under the same inventive spirit should still be included in the scope of protection intended by the present invention.

Claims

1. A single-line control device for a brushless DC motor, characterized in that: It is applicable between the controller and the pre-driver stage of a DC brushless motor, including: A coding and modulation unit, a transmission line, and a demodulation and decoding unit; Among them, the coding and modulation unit is connected to the controller, used to receive the control signal from the controller, and encode and modulate the control signal to generate a modulated signal; the transmission line is connected to the coding and modulation unit, used to transmit the modulated signal to the demodulation and decoding unit; the demodulation and decoding unit is connected to the transmission line, used to demodulate and decode the received modulated signal to generate the original control signal, and then transmit it to the pre-driver stage.

2. The single-wire control device for a brushless DC motor according to claim 1, characterized in that: The DC brushless motor is a single-phase DC brushless motor, and the control signals are four, namely AH, AL, BH, and BL.

3. The single-wire control device for a DC brushless motor according to claim 2, characterized in that: When the control signals [AH, AL, BH, BL] = [0, 0, 0, 0], the single-phase DC brushless motor is in the PH_OFF state, and the modulated signal output by the coding and modulation unit is 0; When the control signals [AH, AL, BH, BL] = [1, 0, 0, X], the single-phase DC brushless motor is in the PH1 state, and the modulated signal output by the coding and modulation unit is MBL; When the control signals [AH, AL, BH, BL] = [0, X, 1, 0], the single-phase DC brushless motor is in the PH2 state, and the modulated signal output by the coding and modulation unit is MAL; Among them, X indicates that the signal levels 0 and 1 are indistinguishable, and PH1, PH2, and PH_OFF respectively represent three states of the single-phase DC brushless motor; MAL and MBL are the modulated AL and BL signals respectively.

4. The single-wire control device for a brushless DC motor according to claim 3, characterized in that: The modulation function of AL is MAL = 0.3xAL + 0.7xVDD, and the modulation function of BL is MBL = 0.3xBL + 0.2xVDD, where VDD is the voltage source.

5. The single-wire control device for a brushless DC motor according to claim 4, characterized in that: The demodulation and decoding unit further includes a comparison module and a combinational logic circuit; the comparison module performs operations on the modulated signal through a comparison program to generate four signals, namely PH1HL, PH2, PH2HL, and PHOFF, and the combinational logic circuit then maps the four signals PH1HL, PH2, PH2HL, and PHOFF into four original control signals, namely AL, AH, BL, and BH.

6. The single-wire control device for a brushless DC motor according to claim 5, characterized in that: The operations of the comparison program are as follows: If the modulated signal > VDDx85%, then PH2HL = 1, otherwise PH2HL = 0; If the modulated signal > VDDx60%, then PH2 = 1, otherwise PH2 = 0; If the modulated signal < VDDx15%, then PHOFF = 1, otherwise PHOFF = 0; If the modulated signal > VDDx35%, then PH1HL = 1, otherwise PH1HL = 0.

7. The single-wire control device for a brushless DC motor according to claim 6, characterized in that: The operation of the combinational logic circuit is as follows: AL = PH2HL ∧ BH; BL = AH ∧ PH1HL; Among them, ∧ is the logical operation symbol and, ∨ is the logical operation symbol or, The logical operator is not.

8. The single-wire control device for a brushless DC motor according to claim 1, characterized in that: The DC brushless motor is a three-phase DC brushless motor, and the control signals are six, namely AH, AL, BH, BL, CH, and CL.

9. The single-wire control device for a brushless DC motor according to claim 8, characterized in that: When the control signal [AH, AL, BH, BL, CH, CL] = [1, 0, 0, 0, 0, X], the three-phase DC brushless motor is in the PH1 state, the modulation signal output by the encoder modulation unit is MCL, and the basic voltage is 0V; When [AH, AL, BH, BL, CH, CL] = [1, 0, 0, X, 0, 0], the three-phase brushless DC motor is in the PH2 state, the modulation signal output by the code modulation unit is MBL, and the basic voltage is VDDx0.8; When [AH, AL, BH, BL, CH, CL] = [0, 0, 0, X, 1, 0], the three-phase DC brushless motor is in the PH3 state, the modulation signal output by the code modulation unit is MBL, and the basic voltage is VDDx0.5; When [AH, AL, BH, BL, CH, CL] = [0, X, 0, 0, 1, 0], the three-phase DC brushless motor is in the PH4 state, the modulation signal output by the encoder modulation unit is MAL, and the basic voltage is VDDx0.8; When [AH, AL, BH, BL, CH, CL] = [0, X, 1, 0, 0, 0], the three-phase brushless DC motor is in the PH5 state, the modulation signal output by the encoder modulation unit is MAL, and the basic voltage is VDDx0.5; When [AH, AL, BH, BL, CH, CL] = [0, 0, 1, 0, 0, X], the three-phase brushless DC motor is in the PH6 state, the modulation signal output by the code modulation unit is MCL, and the basic voltage is VDDx0.8; Among them, X represents that there is no difference between signal levels 0 and 1, PH1, PH2, PH3, PH4, PH5, and PH6 respectively represent six states of the three-phase DC brushless motor, the basic voltage is the voltage value added to the modulation signal before the modulation is completed, and VDD is the voltage source.

10. The single-wire control device for a brushless DC motor according to claim 9, characterized in that: The modulation functions of AL, BL, and CL are MAL=0.2xAL+the basic voltage, MBL=0.2xBL+the basic voltage, and MCL=0.2xCL+the basic voltage. MAL, MBL, and MCL are the modulated signals of AL, BL, and CL respectively.

11. The single-wire control device for a brushless DC motor according to claim 10, characterized in that: The demodulation and decoding unit further includes a comparison module and a combinational logic circuit; the comparison module operates the modulated signal through a comparison program to generate five signals, namely, PH1, PH1HL, PH246, PH246HL, and PH35; the PH246 signal passes through a wave edge detector and a state counter with the PH1 signal, and then outputs five signals, namely, PH2, PH3, PH4, PH5, and PH6; and the combinational logic circuit then images the ten signals, namely, PH1, PH1HL, PH246, PH246HL, PH35, PH2, PH3, PH4, PH5, and PH6, into six original control signals, namely, AL, AH, BL, BH, CH, and CL.

12. The single-wire control device for a brushless DC motor according to claim 11, characterized in that: The operation of the comparison program is as follows: If the modulation signal > VDD x 95%, then PH246HL = 1; otherwise, PH246HL = 0; If the modulation signal > VDD x 60%, then PH35HL = 1; otherwise, PH35HL = 0; If the modulation signal > VDD x 10%, then PH1HL = 1; otherwise, PH1HL = 0; If the modulation signal > VDD x 75%, then PH246 = 1; otherwise, PH246 = 0; If the modulation signal < VDD x 30%, then PH1 = 1; otherwise, PH1 = 0.

13. The single-wire control device for a brushless DC motor according to claim 12, characterized in that: The operation of the combinational logic circuit is as follows: AH = PH1 ∨ PH2; BH = PH5 ∨ PH6; CH = PH3 ∨ PH4; AL = (PH246HL ∧ PH4) ∨ (PH35HL ∧ PH5); BL = (PH246HL ∧ PH2) ∨ (PH35HL ∧ PH3); CL = (PH246HL ∧ PH6) ∨ (PH1HL ∧ PH1); Wherein, ∧ is the logical operation symbol AND, and ∨ is the logical operation symbol OR.

14. The single-wire control device for a brushless DC motor according to claim 1, characterized in that: The encoding modulation unit is integrated in the controller of the DC brushless motor; and the demodulation and decoding unit is integrated in the pre-drive stage of the DC brushless motor, or the demodulation and decoding unit is integrated in both the pre-drive stage and the power stage of the DC brushless motor.

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