Contactor starting circuit and contactor control system

Abstract

The invention discloses a contactor starting circuit and a contactor control system. The contactor starting circuit comprises a boost circuit used for boosting an input power supply voltage so that an output voltage of the boost circuit is higher than the power supply voltage; the sampling circuit is connected with the output end of the booster circuit and is used for collecting the output voltage; the driving circuit is connected with the output end of the booster circuit and is used for providing stable starting voltage for a contactor coil; and the microcontroller is suitable for controlling the driving circuit according to the output voltage acquired by the sampling circuit. When the output voltage of the booster circuit reaches the preset voltage, the microcontroller controls the driving circuit to provide the stable starting voltage for the contactor coil, so that the contactor coil has the constant starting current in the starting stage, and the duration time of the constant starting current is not shorter than the preset time. According to the invention, the starting current of the contactor coil can be improved to more than 3A, and the application range of the contactor product is expanded.

Description

TECHNICAL FIELD

[0001] The present application relates to a contactor starting circuit and a contactor control system comprising the same. BACKGROUND

[0002] In the prior art, the core competitive advantage of high-voltage contactors is small size, which matches the miniaturized application requirements provided by customers. However, the starting current of the coil of a miniaturized high-voltage contactor is large, usually reaching 3A or even higher. However, the power supply of many customers is limited, and the power supply current is generally not more than 1.5A, which cannot meet the current requirement of the coil starting. This results in that the existing high-voltage contactors cannot be applied in many customers' products. SUMMARY

[0003] The present application aims to solve at least one of the above problems and defects in the prior art.

[0004] According to one aspect of the present application, a contactor starting circuit is provided. The contactor starting circuit comprises: a boost circuit configured to boost an input power supply voltage Vin, so that an output voltage Vout of the boost circuit is higher than the power supply voltage Vin; a sampling circuit connected to an output end of the boost circuit, configured to collect the output voltage Vout of the boost circuit; a driving circuit connected to the output end of the boost circuit, configured to provide a stable starting voltage to a contactor coil; and a microcontroller adapted to control the driving circuit according to the output voltage Vout of the boost circuit collected by the sampling circuit. When the output voltage Vout of the boost circuit reaches a predetermined voltage, the microcontroller controls the driving circuit to provide a stable starting voltage to the contactor coil, so that the contactor coil has a constant starting current in the starting stage and the duration of the constant starting current is not less than a predetermined time.

[0005] According to one exemplary embodiment of the present application, when the output voltage Vout of the boost circuit does not reach the predetermined voltage, the microcontroller controls the driving circuit to cut off the electrical connection between the output end of the boost circuit and the contactor coil; when the output voltage Vout of the boost circuit reaches the predetermined voltage, the microcontroller controls the driving circuit to connect the electrical connection between the output end of the boost circuit and the contactor coil.

[0006] According to another exemplary embodiment of the present invention, the microcontroller is further adapted to control the boost circuit based on the output voltage Vout of the boost circuit acquired by the sampling circuit; when the output voltage Vout of the boost circuit does not reach the predetermined voltage, the microcontroller controls the boost circuit to continue increasing the output voltage Vout; when the output voltage Vout of the boost circuit reaches the predetermined voltage, the microcontroller controls the boost circuit to stop increasing the output voltage Vout.

[0007] According to another exemplary embodiment of the present invention, the contactor starting circuit can ensure that the starting current of the contactor coil is not less than 3 amperes and that the duration of the starting current is not less than 60 milliseconds.

[0008] According to another exemplary embodiment of the present invention, the boost circuit includes: an inductor L1, one end of which is connected to a power supply; an N-type MOSFET Q2, the drain of which is connected to the other end of the inductor L1, the source of which is grounded, and the gate of which is connected to an output port of the microcontroller; a diode D1, the anode of which is connected to the other end of the inductor L1 and the drain of the N-type MOSFET Q2; and a capacitor C1, one end of which is connected to the cathode of the diode D1, and the other end of which is grounded, wherein one end of the inductor L1 serves as the input terminal of the boost circuit, and one end of the capacitor C1 serves as the output terminal of the boost circuit.

[0009] According to another exemplary embodiment of the present invention, the capacitance value of capacitor C1 can be calculated according to the following formula: C1 = I*T / (Vout-Vin), where, C1 is the capacitance value of capacitor C1, I is the starting current of the contactor coil, T is the duration of the starting current of the contactor coil, Vout is the output voltage of the boost circuit, and Vin is the input power supply voltage.

[0010] According to another exemplary embodiment of the present invention, one output port of the microcontroller is used to output a PWM wave to the gate of the N-type MOSFET Q2, thereby enabling the maximum output voltage Vmax of the boost circuit to be controlled by adjusting the duty cycle D of the PWM wave. The maximum output voltage Vmax of the boost circuit can be calculated according to the following formula: Vmax = Vin / (1-D), where Vmax is the maximum output voltage of the boost circuit, Vin is the input power supply voltage, and D is the duty cycle of the PWM wave.

[0011] According to another exemplary embodiment of the present invention, the boost circuit further includes: a resistor R4, one end of which is connected to the output port of the microcontroller and the other end of which is connected to the gate of the N-type MOS transistor Q2; and a resistor R5, one end of which is connected to one end of the resistor R4 and the output port of the microcontroller, and the other end of which is grounded.

[0012] According to another exemplary embodiment of the present invention, the sampling circuit includes: a resistor R1, one end of which is connected to the output terminal of the boost circuit; and a resistor R6, one end of which is connected to the other end of the resistor R1, and the other end is grounded. An analog-to-digital converter (ADC) of the microcontroller is connected to the other end of the resistor R1 and one end of the resistor R6 to acquire a sampling voltage V1. The output voltage Vout of the boost circuit can be calculated according to the following formula:

[0013] Vout = V1*(R1+R6) / R6, where Vout is the output voltage of the boost circuit, and V1 is the sampled voltage obtained by the microcontroller.

[0014] According to another exemplary embodiment of the present invention, the driving circuit includes: a P-type MOSFET Q1, the source of which is connected to the output terminal of the boost circuit; a resistor R3, one end of which is connected to the output terminal of the boost circuit and the other end of which is connected to the gate of the P-type MOSFET Q1; an N-type MOSFET Q4, the drain of which is connected to the other end of the resistor R3 and the gate of the P-type MOSFET Q1, and the source of which is grounded; a resistor R2, one end of which is connected to the drain of the P-type MOSFET Q1; and a Zener diode D2, the negative terminal of which is connected to the other end of the resistor R2 and the positive terminal of which is grounded; a general purpose input / output port GPIO1 of the microcontroller is connected to the gate of the N-type MOSFET Q4; and the negative terminal of the Zener diode D2 is used to provide a stable driving voltage.

[0015] According to another exemplary embodiment of the present invention, when the output voltage Vout of the boost circuit does not reach the predetermined voltage, a general-purpose input / output port GPIO1 of the microcontroller outputs a low level to the gate of the N-type MOSFET Q4, so that both the N-type MOSFET Q4 and the P-type MOSFET Q1 are in the off state, thereby cutting off the electrical connection between the driving circuit and the boost circuit; when the output voltage Vout of the boost circuit reaches the predetermined voltage, a general-purpose input / output port GPIO1 of the microcontroller outputs a high level to the gate of the N-type MOSFET Q4, so that both the N-type MOSFET Q4 and the P-type MOSFET Q1 are in the on state, thereby connecting the electrical connection between the driving circuit and the boost circuit.

[0016] According to another exemplary embodiment of the present invention, the driving circuit further includes: an N-type MOSFET Q3, the gate of which is connected to the negative terminal of the Zener diode D2 and the other end of the resistor R2, and the drain of which is connected to the drain of the P-type MOSFET Q1 and one end of the resistor R2; and a freewheeling diode D3, the negative terminal of which is connected to the source of the N-type MOSFET Q3, and the positive terminal of which is grounded, wherein the positive and negative terminals of the freewheeling diode D3 are respectively connected to the two ends of the contactor coil.

[0017] According to another exemplary embodiment of the present invention, the starting voltage provided by the driving circuit to the contactor coil and the starting current of the contactor coil during the starting phase can be calculated according to the following formula: V = VD² - VQ³ I = V / R, V is the starting voltage provided by the driving circuit to the contactor coil, VD2 is the voltage across the Zener diode D2, VQ3 is the threshold voltage of the N-type MOSFET Q3, I is the starting current of the contactor coil during the starting phase, and R is the resistance of the contactor coil.

[0018] According to another exemplary embodiment of the present invention, the driving circuit further includes: a first connection terminal connected to the negative terminal of the freewheeling diode D3 and the source terminal of the N-type MOS transistor Q3; and a second connection terminal connected to the positive terminal of the freewheeling diode D3 and grounded, wherein the first connection terminal and the second connection terminal are used to connect to the two ends of the contactor coil respectively.

[0019] According to another exemplary embodiment of the present invention, the driving circuit further includes: a resistor R7, one end of which is connected to the general purpose input / output port GPIO1 of the microcontroller; and a resistor R8, one end of which is connected to the other end of the resistor R7 and the other end is grounded, wherein the gate of the N-type MOS transistor Q4 is connected to the other end of the resistor R7 and one end of the resistor R8.

[0020] According to another exemplary embodiment of the present invention, the contactor starting circuit further includes an LDO circuit, the input of which is connected to a power supply and the output of which is connected to the positive power supply terminal VDD of the microcontroller, for supplying power to the microcontroller.

[0021] According to another exemplary embodiment of the present invention, the LDO circuit includes: a low-dropout linear regulator U1, the input of which is connected to the positive terminal of the power supply, and the output of which is connected to the positive power supply terminal VDD of the microcontroller; capacitors C5 and C3, one end of which is connected to the input terminal of the low-dropout linear regulator U1, and the other end of which is grounded; and capacitors C4 and C6, one end of which is connected to the output terminal of the low-dropout linear regulator U1, and the other end of which is grounded; and the input terminal of the boost circuit is connected to the input terminal of the low-dropout linear regulator U1.

[0022] According to another exemplary embodiment of the present invention, the LDO circuit further includes: a power supply positive terminal connected to the input terminal of the low dropout linear regulator U1, the input terminal of the boost circuit, and one end of the capacitors C5 and C3; and a power supply negative terminal connected to the other end of the capacitors C5 and C3, wherein the power supply positive terminal and the power supply negative terminal are used to connect to the positive and negative terminals of the power supply, respectively.

[0023] According to another aspect of the present invention, a contactor control system is provided. The contactor control system includes: the aforementioned contactor starting circuit, configured to provide a stable starting voltage to the contactor coil, such that the contactor coil has a constant starting current during the starting phase, and the duration of the constant starting current is not less than a predetermined time; and a contactor holding circuit, configured to provide a stable holding voltage to the contactor coil after the contactor starting circuit has completed the starting of the contactor coil, such that the contactor coil has a constant holding current during the holding phase, wherein the holding voltage of the contactor coil during the holding phase is less than the starting voltage of the contactor coil during the starting phase, and the holding current of the contactor coil during the holding phase is less than the starting current of the contactor coil during the starting phase.

[0024] According to an exemplary embodiment of the present invention, the contactor holding circuit can ensure that the holding current of the contactor coil during the holding phase is not higher than 0.65 amps, and the contactor starting circuit can ensure that the starting current of the contactor coil during the starting phase is not less than 3 amps.

[0025] According to another exemplary embodiment of the present invention, another general-purpose input / output port GPIO2 of the microcontroller is connected to the contactor holding circuit for controlling the contactor holding circuit to provide a stable holding voltage to the contactor coil. After the contactor starting circuit has completed the starting of the contactor coil, the microcontroller controls the boost circuit to stop increasing the output voltage Vout and controls the drive circuit to disconnect the electrical connection between the drive circuit and the boost circuit.

[0026] In the aforementioned exemplary embodiments of the present invention, the contactor starting circuit increases the starting current of the contactor coil by rapidly storing energy by increasing the power supply voltage, so that the starting current of the contactor coil can reach more than 3A, thereby expanding the application range of the contactor product.

[0027] Other objects and advantages of the invention will become apparent from the following description of the invention with reference to the accompanying drawings, and will help to provide a comprehensive understanding of the invention. Attached Figure Description

[0028] Figure 1 This diagram shows a functional block diagram of a contactor starting circuit according to an exemplary embodiment of the present invention. Figure 2 A circuit diagram showing a contactor starting circuit according to an exemplary embodiment of the present invention is shown; Figure 3 This diagram shows a functional block diagram of a contactor control system according to an exemplary embodiment of the present invention. Detailed Implementation

[0029] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation thereof.

[0030] Furthermore, in the following detailed description, numerous specific details are set forth for ease of explanation to provide a thorough understanding of the embodiments disclosed herein. However, it will be apparent that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and apparatuses are illustrated to simplify the figures.

[0031] According to a general technical concept of the present invention, a contactor starting circuit is provided. The contactor starting circuit includes: a boost circuit for increasing an input power supply voltage Vin, such that the output voltage Vout of the boost circuit is higher than the power supply voltage Vin; a sampling circuit connected to the output terminal of the boost circuit for acquiring the output voltage Vout of the boost circuit; a drive circuit connected to the output terminal of the boost circuit for providing a stable starting voltage to the contactor coil; and a microcontroller adapted to control the drive circuit based on the output voltage Vout of the boost circuit acquired by the sampling circuit. When the output voltage Vout of the boost circuit reaches a predetermined voltage, the microcontroller controls the drive circuit to provide a stable starting voltage to the contactor coil, such that the contactor coil has a constant starting current during the starting phase, and the duration of this constant starting current is not less than a predetermined time.

[0032] According to another general technical concept of the present invention, a contactor control system is provided. The contactor control system includes: the aforementioned contactor starting circuit, configured to provide a stable starting voltage to the contactor coil, such that the contactor coil has a constant starting current during the starting phase, and the duration of the constant starting current is not less than a predetermined time; and a contactor holding circuit, configured to provide a stable holding voltage to the contactor coil after the contactor starting circuit has completed the starting of the contactor coil, such that the contactor coil has a constant holding current during the holding phase, wherein the holding voltage of the contactor coil during the holding phase is less than the starting voltage of the contactor coil during the starting phase, and the holding current of the contactor coil during the holding phase is less than the starting current of the contactor coil during the starting phase.

[0033] Figure 1 This diagram shows a functional block diagram of a contactor starting circuit according to an exemplary embodiment of the present invention. Figure 2 A circuit diagram showing a contactor starting circuit according to an exemplary embodiment of the present invention is shown.

[0034] like Figure 1 and Figure 2 As shown, in an exemplary embodiment of the present invention, a contactor starting circuit is disclosed. The contactor starting circuit includes: a boost circuit 1, a sampling circuit 2, a drive circuit 3, and a microcontroller 5. The boost circuit 1 is used to increase the input power supply voltage Vin, so that the output voltage Vout of the boost circuit 1 is higher than the power supply voltage Vin. The sampling circuit 2 is connected to the output terminal of the boost circuit 1 and is used to acquire the output voltage Vout of the boost circuit 1. The drive circuit 3 is connected to the output terminal of the boost circuit 1 and is used to provide a stable starting voltage to the contactor coil. The microcontroller 5 is adapted to control the drive circuit 3 according to the output voltage Vout of the boost circuit 1 acquired by the sampling circuit 2. When the output voltage Vout of the boost circuit 1 reaches a predetermined voltage, the microcontroller 5 controls the drive circuit 3 to provide a stable starting voltage to the contactor coil, so that the contactor coil has a constant starting current during the starting phase, and the duration of this constant starting current is not less than a predetermined time.

[0035] like Figure 1 and Figure 2 As shown in the illustrated embodiment, when the output voltage Vout of the boost circuit 1 does not reach the predetermined voltage, the microcontroller 5 controls the drive circuit 3 to disconnect the electrical connection between the output terminal of the boost circuit 1 and the contactor coil; when the output voltage Vout of the boost circuit 1 reaches the predetermined voltage, the microcontroller 5 controls the drive circuit 3 to connect the electrical connection between the output terminal of the boost circuit 1 and the contactor coil.

[0036] like Figure 1and Figure 2 As shown in the illustrated embodiment, the microcontroller 5 is also adapted to control the boost circuit 1 based on the output voltage Vout of the boost circuit 1 collected by the sampling circuit 2; when the output voltage Vout of the boost circuit 1 does not reach the predetermined voltage, the microcontroller 5 controls the boost circuit 1 to continue increasing the output voltage Vout; when the output voltage Vout of the boost circuit 1 reaches the predetermined voltage, the microcontroller 5 controls the boost circuit 1 to stop increasing the output voltage Vout.

[0037] like Figure 1 and Figure 2 As shown in the illustrated embodiment, the contactor starting circuit can ensure that the starting current of the contactor coil is not less than 3 amps and that the duration of the starting current is not less than 60 milliseconds.

[0038] like Figure 1 and Figure 2 As shown in the illustrated embodiment, the boost circuit 1 includes an inductor L1, an N-type MOSFET Q2, a diode D1, and a capacitor C1. One end of the inductor L1 is connected to a power supply. The drain of the N-type MOSFET Q2 is connected to the other end of the inductor L1, its source is grounded, and its gate is connected to an output port of the microcontroller 5. The anode of the diode D1 is connected to both the other end of the inductor L1 and the drain of the N-type MOSFET Q2. One end of the capacitor C1 is connected to the cathode of the diode D1, and the other end is grounded. One end of the inductor L1 serves as the input terminal of the boost circuit 1, and one end of the capacitor C1 serves as the output terminal of the boost circuit 1.

[0039] like Figure 1 and Figure 2 As shown in the illustrated embodiment, the capacitance value of capacitor C1 can be calculated according to the following formula: C1 = I*T / (Vout-Vin) where C1 is the capacitance value of capacitor C1, I is the starting current of the contactor coil, T is the duration of the starting current of the contactor coil, Vout is the output voltage of boost circuit 1, and Vin is the input power supply voltage.

[0040] like Figure 1 and Figure 2 As shown in the illustrated embodiment, one output port of the microcontroller 5 is used to output a PWM wave to the gate of the N-type MOSFET Q2, thereby enabling the maximum output voltage Vmax of the boost circuit 1 to be controlled by adjusting the duty cycle D of the PWM wave. The maximum output voltage Vmax of boost circuit 1 can be calculated using the following formula: Vmax = Vin / (1-D), where Vmax is the maximum output voltage of boost circuit 1, Vin is the input power supply voltage, and D is the duty cycle of the PWM wave.

[0041] like Figure 1 and Figure 2 As shown in the illustrated embodiment, the boost circuit 1 further includes resistors R4 and R5. One end of resistor R4 is connected to an output port of the microcontroller 5, and the other end is connected to the gate of the N-type MOSFET Q2. One end of resistor R5 is connected to one end of resistor R4 and an output port of the microcontroller 5, and the other end is grounded.

[0042] like Figure 1 and Figure 2 As shown in the illustrated embodiment, the sampling circuit 2 includes resistors R1 and R6. One end of resistor R1 is connected to the output terminal of the boost circuit 1. One end of resistor R6 is connected to the other end of resistor R1, and the other end is grounded. An analog-to-digital converter (ADC) of the microcontroller 5 is connected to the other end of resistor R1 and one end of resistor R6 to acquire a sampling voltage V1. The output voltage Vout of the boost circuit 1 can be calculated according to the following formula:

[0043] Vout = V1*(R1+R6) / R6, where Vout is the output voltage of boost circuit 1, and V1 is the sampling voltage obtained by microcontroller 5.

[0044] like Figure 1 and Figure 2 As shown in the illustrated embodiment, the driving circuit 3 includes: a P-type MOSFET Q1, a resistor R3, an N-type MOSFET Q4, a resistor R2, and a Zener diode D2. The source of the P-type MOSFET Q1 is connected to the output terminal of the boost circuit 1. One end of the resistor R3 is connected to the output terminal of the boost circuit 1, and the other end is connected to the gate of the P-type MOSFET Q1. The drain of the N-type MOSFET Q4 is connected to the other end of the resistor R3 and the gate of the P-type MOSFET Q1, and its source is grounded. One end of the resistor R2 is connected to the drain of the P-type MOSFET Q1. The cathode of the Zener diode D2 is connected to the other end of the resistor R2, and its anode is grounded. A general purpose input / output port GPIO1 of the microcontroller 5 is connected to the gate of the N-type MOSFET Q4. The Zener diode D2 provides a stable driving voltage.

[0045] like Figure 1 and Figure 2As shown in the illustrated embodiment, when the output voltage Vout of the boost circuit 1 does not reach the predetermined voltage, a general-purpose input / output port GPIO1 of the microcontroller 5 outputs a low level to the gate of the N-type MOSFET Q4, causing both the N-type MOSFET Q4 and the P-type MOSFET Q1 to be in the off state, thereby cutting off the electrical connection between the drive circuit 3 and the boost circuit 1. When the output voltage Vout of the boost circuit 1 reaches the predetermined voltage, a general-purpose input / output port GPIO1 of the microcontroller 5 outputs a high level to the gate of the N-type MOSFET Q4, causing both the N-type MOSFET Q4 and the P-type MOSFET Q1 to be in the on state, thereby connecting the electrical connection between the drive circuit 3 and the boost circuit 1.

[0046] like Figure 1 and Figure 2 As shown in the illustrated embodiment, the driving circuit 3 further includes an N-type MOSFET Q3 and a freewheeling diode D3. The gate of the N-type MOSFET Q3 is connected to the cathode of the Zener diode D2 and the other end of the resistor R2, and its drain is connected to the drain of the P-type MOSFET Q1 and one end of the resistor R2. The cathode of the freewheeling diode D3 is connected to the source of the N-type MOSFET Q3, and its anode is grounded. The anode and cathode of the freewheeling diode D3 are used to connect to the two ends of the contactor coil, respectively. In the illustrated embodiment, the Zener diode D2 is used to drive the N-type MOSFET Q3, thereby stabilizing the source voltage of the N-type MOSFET Q3 and achieving constant current.

[0047] like Figure 1 and Figure 2 As shown in the illustrated embodiment, the starting voltage provided by the drive circuit 3 to the contactor coil and the starting current of the contactor coil during the starting phase can be calculated according to the following formula: V = VD² - VQ³ I = V / R, V is the starting voltage provided by drive circuit 3 to the contactor coil, VD2 is the voltage across Zener diode D2, VQ3 is the threshold voltage of N-type MOSFET Q3, I is the starting current of the contactor coil during the starting phase, and R is the resistance of the contactor coil.

[0048] like Figure 1 and Figure 2 As shown in the illustrated embodiment, the driving circuit 3 further includes a first connection terminal P1 and a second connection terminal P2. The first connection terminal P1 is connected to the negative terminal of the freewheeling diode D3 and the source terminal of the N-type MOSFET Q3. The second connection terminal P2 is connected to the positive terminal of the freewheeling diode D3 and grounded. The first connection terminal P1 and the second connection terminal P2 are used to connect to the two ends of the contactor coil, respectively.

[0049] like Figure 1 and Figure 2As shown in the illustrated embodiment, the driving circuit 3 further includes resistors R7 and R8. One end of resistor R7 is connected to a general purpose input / output port GPIO1 of the microcontroller 5. One end of resistor R8 is connected to the other end of resistor R7, and the other end is grounded. The gate of the N-type MOSFET Q4 is connected to the other end of resistor R7 and one end of resistor R8.

[0050] like Figure 1 and Figure 2 As shown in the illustrated embodiment, the contactor starting circuit also includes an LDO circuit 4. The input terminal of the LDO circuit 4 is connected to a power supply, and its output terminal is connected to the positive power supply terminal VDD of the microcontroller 5 to supply power to the microcontroller 5. The supply voltage is +5V.

[0051] like Figure 1 and Figure 2 As shown in the illustrated embodiment, the LDO circuit 4 includes: a low-dropout linear regulator U1, capacitors C5, C3, C4, and C6. The input terminal of the low-dropout linear regulator U1 is connected to the positive terminal of the power supply, and its output terminal is connected to the positive power supply terminal VDD of the microcontroller 5. One end of capacitors C5 and C3 is connected to the input terminal of the low-dropout linear regulator U1, and the other end is grounded. One end of capacitors C4 and C6 is connected to the output terminal of the low-dropout linear regulator U1, and the other end is grounded. The input terminal of the boost circuit 1 is connected to the input terminal of the low-dropout linear regulator U1.

[0052] like Figure 2 and Figure 1 As shown in the illustrated embodiment, the LDO circuit 4 further includes a positive power supply connection terminal P3 and a negative power supply connection terminal P4. The positive power supply connection terminal P3 is connected to the input terminal of the low-dropout linear regulator U1, the input terminal of the boost circuit 1, and one end of capacitors C5 and C3. The negative power supply connection terminal P4 is connected to the other end of capacitors C5 and C3. The positive power supply connection terminal P3 and the negative power supply connection terminal P4 are used to connect to the positive and negative terminals of the power supply, respectively.

[0053] Please note, Figure 2 This is merely an exemplary circuit diagram of the present invention, and the values ​​of the various electronic components are only exemplary and can be adjusted according to actual conditions. Furthermore, the implementation... Figure 2 The circuit diagram shown in the functional block diagram is not limited to... Figure 3 The circuit diagram shown is used. Figures 1 to 3 In the circuit diagram shown, unless otherwise specified, grounding usually refers to connecting to the negative terminal of the power supply.

[0054] Figures 1 to 3 This diagram shows a functional block diagram of a contactor control system according to an exemplary embodiment of the present invention.

[0055] like Figures 1 to 3 As shown, in another exemplary embodiment of the present invention, a contactor control system is also disclosed. The contactor control system includes the aforementioned contactor starting circuit and contactor holding circuit 6. The contactor starting circuit provides a stable starting voltage to the contactor coil, so that the contactor coil has a constant starting current during the starting phase, and the duration of this constant starting current is not less than a predetermined time. The contactor holding circuit 6 provides a stable holding voltage to the contactor coil after the contactor starting circuit has completed the starting of the contactor coil, so that the contactor coil has a constant holding current during the holding phase. The holding voltage of the contactor coil during the holding phase is less than the starting voltage of the contactor coil during the starting phase, and the holding current of the contactor coil during the holding phase is less than the starting current of the contactor coil during the starting phase.

[0056] like ​ As shown in the illustrated embodiment, the contactor holding circuit 6 ensures that the holding current of the contactor coil during the holding phase does not exceed 0.65 amps, thus reducing energy consumption. The contactor starting circuit ensures that the starting current of the contactor coil during the starting phase is not less than 3 amps, thus ensuring that the contactor coil can be reliably started.

[0057] like ​ As shown in the illustrated embodiment, another general-purpose input / output port GPIO2 of the microcontroller 5 is connected to the contactor holding circuit 6, used to control the contactor holding circuit 6 to provide a stable holding voltage to the contactor coil. After the contactor starting circuit has completed the starting of the contactor coil, the microcontroller 5 controls the boost circuit 1 to stop increasing the output voltage Vout and controls the drive circuit 3 to disconnect the electrical connection between the drive circuit 3 and the boost circuit 1.

[0058] Those skilled in the art will understand that the embodiments described above are exemplary and can be improved upon. The structures described in the various embodiments can be freely combined without causing structural or principle conflicts, and these changes should fall within the protection scope of this invention.

[0059] Although the invention has been described in conjunction with the accompanying drawings, the embodiments disclosed in the drawings are intended to illustrate preferred embodiments of the invention and should not be construed as limiting the invention.

[0060] While some embodiments of the general concept of the invention have been shown and described, those skilled in the art will understand that changes may be made to these embodiments without departing from the principles and spirit of the general concept of the invention, the scope of which is defined by the claims and their equivalents.

[0061] It should be noted that the word "comprising" does not exclude other elements or steps, and the words "a" or "an" do not exclude multiple elements. Furthermore, any reference numerals in the claims should not be construed as limiting the scope of the invention.

Claims

1. A contactor starting circuit, characterized in that, include: A boost circuit (1) is used to increase the input power supply voltage Vin, so that the output voltage Vout of the boost circuit (1) is higher than the power supply voltage Vin; The sampling circuit (2) is connected to the output terminal of the boost circuit (1) and is used to collect the output voltage Vout of the boost circuit (1); The driving circuit (3) is connected to the output terminal of the boost circuit (1) and is used to provide a stable starting voltage to the contactor coil; and The microcontroller (5) is adapted to control the drive circuit (3) based on the output voltage Vout of the boost circuit (1) acquired by the sampling circuit (2). When the output voltage Vout of the boost circuit (1) reaches a predetermined voltage, the microcontroller (5) controls the drive circuit (3) to provide a stable starting voltage to the contactor coil, so that the contactor coil has a constant starting current during the starting phase and the duration of the constant starting current is not less than a predetermined time.

2. The contactor starting circuit according to claim 1, characterized in that: When the output voltage Vout of the boost circuit (1) does not reach the predetermined voltage, the microcontroller (5) controls the drive circuit (3) to disconnect the electrical connection between the output terminal of the boost circuit (1) and the contactor coil; When the output voltage Vout of the boost circuit (1) reaches the predetermined voltage, the microcontroller (5) controls the drive circuit (3) to connect the electrical connection between the output terminal of the boost circuit (1) and the contactor coil.

3. The contactor starting circuit according to claim 1, characterized in that: The microcontroller (5) is also adapted to control the boost circuit (1) based on the output voltage Vout of the boost circuit (1) collected by the sampling circuit (2); When the output voltage Vout of the boost circuit (1) does not reach the predetermined voltage, the microcontroller (5) controls the boost circuit (1) to continue to increase the output voltage Vout; When the output voltage Vout of the boost circuit (1) reaches the predetermined voltage, the microcontroller (5) controls the boost circuit (1) to stop increasing the output voltage Vout.

4. The contactor starting circuit according to claim 1, characterized in that: The contactor starting circuit can ensure that the starting current of the contactor coil is not less than 3 amps and that the duration of the starting current is not less than 60 milliseconds.

5. The contactor starting circuit according to claim 1, characterized in that: The boost circuit (1) includes: Inductor L1, one end of which is connected to the power supply; The drain of the N-type MOS transistor Q2 is connected to the other end of the inductor L1, its source is grounded, and its gate is connected to one of the output ports of the microcontroller (5). Diode D1, its anode is connected to the other end of inductor L1 and the drain of N-type MOSFET Q2; and Capacitor C1 has one end connected to the negative terminal of diode D1, and the other end grounded. One end of the inductor L1 serves as the input terminal of the boost circuit (1), and one end of the capacitor C1 serves as the output terminal of the boost circuit (1).

6. The contactor starting circuit according to claim 5, characterized in that: The capacitance value of capacitor C1 can be calculated using the following formula: C1 = I*T / (Vout-Vin) where C1 is the capacitance value of capacitor C1, I is the starting current of the contactor coil, T is the duration of the starting current of the contactor coil, Vout is the output voltage of the boost circuit (1), and Vin is the input power supply voltage.

7. The contactor starting circuit according to claim 5, characterized in that: One output port of the microcontroller (5) is used to output a PWM wave to the gate of the N-type MOS transistor Q2, thereby controlling the maximum output voltage Vmax of the boost circuit (1) by adjusting the duty cycle D of the PWM wave. The maximum output voltage Vmax of the boost circuit (1) can be calculated according to the following formula: Vmax = Vin / (1-D), where Vmax is the maximum output voltage of the boost circuit (1), Vin is the input power supply voltage, and D is the duty cycle of the PWM wave.

8. The contactor starting circuit according to claim 7, characterized in that: The boost circuit (1) also includes: Resistor R4, one end of which is connected to one output port of the microcontroller (5), and the other end of which is connected to the gate of the N-type MOS transistor Q2; and Resistor R5 has one end connected to one end of resistor R4 and one output port of the microcontroller (5), and the other end grounded.

9. The contactor starting circuit according to claim 1, characterized in that: The sampling circuit (2) includes: Resistor R1, one end of which is connected to the output terminal of the boost circuit (1); and Resistor R6 has one end connected to the other end of resistor R1, and the other end grounded. One analog-to-digital converter (ADC) of the microcontroller (5) is connected to the other end of resistor R1 and one end of resistor R6 to obtain a sampling voltage V1. The output voltage Vout of the boost circuit (1) can be calculated according to the following formula: Vout = V1*(R1+R6) / R6, where Vout is the output voltage of the boost circuit (1), and V1 is the sampling voltage obtained by the microcontroller (5).

10. The contactor starting circuit according to claim 1, characterized in that: The driving circuit (3) includes: The source of the P-type MOS transistor Q1 is connected to the output terminal of the boost circuit (1); Resistor R3, one end of which is connected to the output terminal of the boost circuit (1), and the other end of which is connected to the gate of the P-type MOS transistor Q1; The drain of the N-type MOS transistor Q4 is connected to the other end of the resistor R3 and the gate of the P-type MOS transistor Q1, and its source is grounded. Resistor R2, one end of which is connected to the drain of the P-type MOSFET Q1; and Zener diode D2 has its cathode connected to the other end of resistor R2, and its anode grounded. One of the general purpose input / output ports GPIO1 of the microcontroller (5) is connected to the gate of the N-type MOS transistor Q4. The Zener diode D2 is used to provide a stable driving voltage.

11. The contactor starting circuit according to claim 10, characterized in that: When the output voltage Vout of the boost circuit (1) does not reach the predetermined voltage, a general-purpose input / output port GPIO1 of the microcontroller (5) outputs a low level to the gate of the N-type MOS transistor Q4, so that both the N-type MOS transistor Q4 and the P-type MOS transistor Q1 are in the off state, thereby cutting off the electrical connection between the driving circuit (3) and the boost circuit (1). When the output voltage Vout of the boost circuit (1) reaches the predetermined voltage, a general-purpose input / output port GPIO1 of the microcontroller (5) outputs a high level to the gate of the N-type MOS transistor Q4, so that both the N-type MOS transistor Q4 and the P-type MOS transistor Q1 are in the conducting state, so as to connect the electrical connection between the driving circuit (3) and the boost circuit (1).

12. The contactor starting circuit according to claim 11, characterized in that: The driving circuit (3) further includes: The gate of the N-type MOSFET Q3 is connected to the cathode of the Zener diode D2 and the other end of the resistor R2, and its drain is connected to the drain of the P-type MOSFET Q1 and one end of the resistor R2; and The freewheeling diode D3 has its cathode connected to the source of the N-type MOSFET Q3, and its anode grounded. The positive and negative terminals of the freewheeling diode D3 are used to connect to the two ends of the contactor coil, respectively.

13. The contactor starting circuit according to claim 12, characterized in that: The starting voltage provided by the driving circuit (3) to the contactor coil and the starting current of the contactor coil during the starting phase can be calculated according to the following formula: V = VD² - VQ³ I = V / R, V is the starting voltage provided by the driving circuit (3) to the contactor coil, VD2 is the voltage on the Zener diode D2, VQ3 is the threshold voltage of the N-type MOS transistor Q3, I is the starting current of the contactor coil during the starting phase, and R is the resistance of the contactor coil.

14. The contactor starting circuit according to claim 12, characterized in that: The driving circuit (3) further includes: The first connection terminal (P1) is connected to the negative terminal of the freewheeling diode D3 and the source terminal of the N-type MOSFET Q3; and The second connection terminal (P2) is connected to the positive terminal of the freewheeling diode D3 and grounded. The first connecting terminal (P1) and the second connecting terminal (P2) are used to connect to the two ends of the contactor coil, respectively.

15. The contactor starting circuit according to claim 11, characterized in that: The driving circuit (3) further includes: Resistor R7, one end of which is connected to one of the general purpose input / output ports GPIO1 of the microcontroller (5); and Resistor R8 has one end connected to the other end of resistor R7, and the other end grounded. The gate of the N-type MOS transistor Q4 is connected to the other end of the resistor R7 and one end of the resistor R8.

16. The contactor starting circuit according to any one of claims 1-15, characterized in that, Also includes: The LDO circuit (4) has its input terminal connected to the power supply and its output terminal connected to the positive power supply terminal VDD of the microcontroller (5) to supply power to the microcontroller (5).

17. The contactor starting circuit according to claim 16, characterized in that: The LDO circuit (4) includes: The low-dropout linear regulator U1 has its input terminal connected to the positive terminal of the power supply and its output terminal connected to the positive power supply terminal VDD of the microcontroller (5). Capacitors C5 and C3 have one end connected to the input terminal of the low-dropout linear regulator U1, and the other end grounded; and Capacitors C4 and C6 have one end connected to the output terminal of the low-dropout linear regulator U1, and the other end grounded. The input terminal of the boost circuit (1) is connected to the input terminal of the low-dropout linear regulator U1.

18. The contactor starting circuit according to claim 17, characterized in that: The LDO circuit (4) also includes: The positive terminal of the power supply (P3) is connected to the input terminal of the low-dropout linear regulator U1, the input terminal of the boost circuit (1), and one end of capacitors C5 and C3; and The negative terminal of the power supply (P4) is connected to the other end of capacitors C5 and C3. The positive terminal (P3) and the negative terminal (P4) of the power supply are used to connect to the positive and negative terminals of the power supply, respectively.

19. A contactor control system, characterized in that, include: The contactor starting circuit according to any one of claims 1-18 is used to provide a stable starting voltage to the contactor coil so that the contactor coil has a constant starting current during the starting phase and the duration of the constant starting current is not less than a predetermined time. and The contactor holding circuit (6) is used to provide a stable holding voltage to the contactor coil after the contactor starting circuit has completed the starting of the contactor coil, so that the contactor coil has a constant holding current during the holding phase. The holding voltage of the contactor coil during the holding phase is less than the starting voltage of the contactor coil during the starting phase, and the holding current of the contactor coil during the holding phase is less than the starting current of the contactor coil during the starting phase.

20. The contactor control system according to claim 19, characterized in that: The contactor holding circuit (6) can ensure that the holding current of the contactor coil during the holding phase is not higher than 0.65 amperes, and the contactor starting circuit can ensure that the starting current of the contactor coil during the starting phase is not less than 3 amperes.

21. The contactor control system according to claim 19, characterized in that: Another general purpose input / output port GPIO2 of the microcontroller (5) is connected to the contactor holding circuit (6) and is used to control the contactor holding circuit (6) to provide a stable holding voltage to the contactor coil; After the contactor starting circuit has completed the starting of the contactor coil, the microcontroller (5) controls the boost circuit (1) to stop increasing the output voltage Vout and controls the drive circuit (3) to disconnect the electrical connection between the drive circuit (3) and the boost circuit (1).

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