Heliostat motor braking circuit

Abstract

The invention provides a heliostat motor braking circuit, and the circuit comprises an input unit which comprises a DC power supply input; the brake circuit unit is electrically connected with the input unit and comprises a first diode, a second diode, a first resistor, a second resistor, a third resistor, a fourth resistor and a transistor; the motor control unit is electrically connected with the brake circuit unit and comprises a filter capacitor, a first upper bridge diode, a second upper bridge diode, a third upper bridge diode, a first lower bridge diode, a second lower bridge diode and a third lower bridge diode; and the output unit is electrically connected with the motor control unit and comprises a heliostat motor. According to the invention, a braking effect can be generated when the motor is in a power generation state during normal operation control of the heliostat, a braking effect can also be generated when a direct-current input power supply is short-circuited or an input power supply wiring open-circuit failure occurs, and a motor controller can be prevented from being damaged when a direct-current power supply input positive electrode and a direct-current power supply input negative electrode are reversely connected.

Description

Technical Field

[0001] The invention relates to the technical field of heliostat circuits, and in particular to a heliostat motor braking circuit. Background Art

[0002] Solar tower-type CSP heliostats are concentrating devices composed of reflectors, mirror frames, bases, tracking transmission systems, and control systems. The core components of the tracking transmission system are motors and motor controllers. Under normal working conditions, the motor controller controls the motor rotation to drive the reflector to accurately position the azimuth angle. However, when the power supply of the motor controller fails, the controller cannot control the motor speed and the reflector will lose its torque source. Since heliostats are installed outdoors in harsh environments and have large reflector surfaces, they will shift and move under the influence of outdoor wind. Heliostats are prone to damage the mirror surface and tracking transmission system when not under control. Therefore, braking of the heliostat is one of the designs that need to be considered in the design of the tracking transmission system.

[0003] Among them, the tracking transmission system includes a motor, a motor controller and a reducer. When the movement of the reflector is uncontrolled, the reducer will drive the motor to rotate at a high speed to generate electricity. If the motor is braked by the motor power generation current, the heliostat can be braked. Usually, there are two methods for motor braking: one is to design a normally closed relay at the three-phase output end of the motor controller, and the three-phase winding of the motor is short-circuited by the normally closed relay to realize the motor braking function. The second is to control the switch tube by sending PWM (Pulse width modulation wave) through the motor controller MCU (Microcontroller Unit). The switch tube PWM controls the brake resistor to connect to the positive and negative poles of the bus power supply, and discharges the back electromotive force energy generated by the motor through the brake resistor, thereby realizing the motor braking function. However, the first solution is limited to braking when the motor is static, and the relay is large and has a short life, which is not suitable for applications where the motor controller requires a compact structure, small size and long life; while the second solution is limited to braking when the controller MCU is running. Summary of the invention

[0004] An object of the present invention is to provide a heliostat motor braking circuit for solving the problems of the above-mentioned heliostat braking circuit.

[0005] In a first aspect, the present application provides a heliostat motor braking circuit, comprising:

[0006] an input unit including a DC power input; and

[0007] a braking circuit unit electrically connected to the input unit, comprising a first diode and a second diode, a first resistor, a second resistor, a third resistor and a fourth resistor, and a transistor; and

[0008] a motor control unit electrically connected to the brake circuit unit, comprising a filter capacitor, a first upper bridge diode, a second upper bridge diode and a third upper bridge diode, and a first lower bridge diode, a second lower bridge diode and a third lower bridge diode; and

[0009] The output unit electrically connected to the motor control unit includes a heliostat motor.

[0010] In a possible implementation of the present application, the first diode includes a Schottky diode, the second diode includes a Zener diode, and the transistor includes a P-type MOS transistor.

[0011] In a possible implementation of the present application, the first resistor, the second resistor and the third resistor are voltage-dividing resistors, and the fourth resistor is a braking resistor.

[0012] In a possible implementation of the present application, the DC power input includes a power connector, wherein the positive electrode of the connector is connected to the positive electrode of the first diode, the second resistor and the third resistor, and the negative electrode of the connector is grounded.

[0013] In a possible implementation of the present application, the cathode of the first diode is electrically connected to the first resistor, the second diode and the source of the transistor, and the end of the first resistor away from the cathode of the first diode is electrically connected to the anode of the second diode, the second resistor and the gate of the transistor, wherein the first resistor is connected in parallel with the second diode, the anode of the second diode is connected to the gate of the transistor, and the cathode of the second diode is connected to the source of the transistor.

[0014] In a possible implementation of the present application, one end of the third resistor away from the positive electrode of the connector is grounded, the drain of the transistor is connected to the fourth resistor, and one end of the fourth resistor away from the drain of the transistor is grounded.

[0015] In a possible implementation of the present application, the cathode of the first diode is electrically connected to one end of the filter capacitor, and is electrically connected to the cathode of the first upper bridge diode, the cathode of the second upper bridge diode, and the cathode of the third upper bridge diode.

[0016] In a possible implementation of the present application, one end of the filter capacitor away from the cathode of the first diode is electrically connected to the anode of the first lower bridge diode, the anode of the second lower bridge diode and the anode of the third lower bridge diode.

[0017] In a possible implementation of the present application, the cathode of the first lower bridge diode is electrically connected to the anode of the first upper bridge diode, the cathode of the second lower bridge diode is electrically connected to the anode of the second upper bridge diode, and the cathode of the third lower bridge diode is electrically connected to the anode of the third upper bridge diode.

[0018] In a possible implementation of the present application, the anode of the first upper bridge diode, the anode of the second upper bridge diode, and the anode of the third upper bridge diode are all electrically connected to the heliostat motor.

[0019] As described above, the heliostat motor braking circuit of the present invention can produce a braking effect when the motor is in a power generation state when the heliostat is under normal operation control, and can also produce a braking effect when the DC input power supply is short-circuited or the input power supply wiring is open-circuited. It can prevent the motor controller from being damaged when the positive and negative poles of the DC power supply input are connected in reverse. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Shown is a schematic structural diagram of a heliostat motor braking circuit in one embodiment of the present invention;

[0021] Figure 2 FIG. 2 is a schematic structural diagram of a heliostat motor braking circuit in another embodiment of the present invention.

[0022] Component number description

[0023] 10 Heliostat motor brake circuit

[0024] 11 Input unit

[0025] 12 Braking circuit unit

[0026] 13 Motor control unit

[0027] 14 Output Units

[0028] D1 First diode

[0029] Z1 Second diode

[0030] R1 First resistor

[0031] R2 Second resistor

[0032] R3 The third resistor

[0033] R4 Fourth resistor

[0034] Q1 Transistor

[0035] C1 filter capacitor

[0036] D2 First upper bridge diode

[0037] D3 The first lower bridge diode

[0038] D4 Second upper bridge diode

[0039] D5 Second lower bridge diode

[0040] D6 The third upper bridge diode

[0041] D7 The third lower bridge diode

[0042] D8, D9, D10 spare diodes

[0043] CN1 Connector

[0044] M Heliostat Motor DETAILED DESCRIPTION

[0045] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0046] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0047] See also Figure 1 In one embodiment of the invention, the heliostat motor braking circuit 10 of the present invention includes:

[0048] An input unit 11, including a DC power input; and

[0049] a braking circuit unit 12 electrically connected to the input unit 11, comprising a first diode and a second diode, a first resistor, a second resistor, a third resistor and a fourth resistor, and a transistor; and

[0050] The motor control unit 13 electrically connected to the brake circuit unit 12 includes a filter capacitor, a first upper bridge diode, a second upper bridge diode and a third upper bridge diode, and a first lower bridge diode, a second lower bridge diode and a third lower bridge diode; and

[0051] The output unit 14 electrically connected to the motor control unit 13 includes a heliostat motor.

[0052] It should be noted that if Figure 1 As shown, the input unit 11 includes a DC power input, which can be obtained by connecting an external power line using a connector CN1, and the braking circuit unit 12 includes a first diode D1 and a second diode Z1, a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4, and a transistor Q1, wherein the positive electrode of the DC power supply is connected to the positive electrode of the first diode D1, the negative electrode of the first diode D1 is connected to the first resistor R1, the negative electrode of the second diode Z1 and the source of the transistor Q1, the positive electrode of the first diode D1 is also connected to the second resistor R2 and the third resistor R3, and the fourth resistor R4 is connected to the drain of the transistor Q1; and a motor control unit 13 electrically connected to the braking circuit unit 12, the motor control unit 13 includes a filter circuit A filter capacitor C1, a first upper bridge diode D2, a second upper bridge diode D4 and a third upper bridge diode D6, and a first lower bridge diode D3, a second lower bridge diode D5 and a third lower bridge diode D7, wherein one end of the filter capacitor C1 is connected to the cathode of the first diode D1, the cathode of the first upper bridge diode D2, the cathode of the second upper bridge diode D4 and the cathode of the third upper bridge diode D6, and the other end of the filter capacitor C1 is connected to the anode of the first lower bridge diode D3, the anode of the second lower bridge diode D5 and the anode of the third lower bridge diode D7; and an output unit 14 electrically connected to the motor control unit 13, including a heliostat motor M, wherein the heliostat motor M is connected to the anode of the first upper bridge diode D2, the anode of the second upper bridge diode D4 and the anode of the third upper bridge diode D6.

[0053] Specifically, the first diode D1 includes a Schottky diode, such as a model SGC201BS, the second diode Z1 includes a voltage regulator diode, such as an "18V" voltage regulator diode, the transistor Q1 includes a P-type MOS tube, such as a model MCU28P10Y, the first resistor R1, the second resistor R2 and the third resistor R3 are voltage divider resistors, the fourth resistor R4 is a braking resistor, the first upper bridge diode D2, the second upper bridge diode D4 and the third upper bridge diode D6, and the first lower bridge diode D3, the second lower bridge diode D5 and the third lower bridge diode D7 are all inverter switch body diodes.

[0054] Further, the positive electrode of the connector CN1 is connected to the positive electrode of the first diode D1, the second resistor R2 and the third resistor R3, and the negative electrode of the connector CN1 is grounded, the end of the first resistor R1 away from the negative electrode of the first diode D1 is electrically connected to the positive electrode of the second diode Z1, the second resistor R2 and the gate of the transistor Q1, the end of the third resistor R3 away from the positive electrode of the first diode D1 is grounded, and the third resistor R3 is also electrically connected to the second resistor R2, wherein the end of the third resistor R3 away from the ground is electrically connected to the second resistor R2.

[0055] Furthermore, the anode of the second diode Z1 is connected to the gate of the transistor Q1, the cathode of the second diode Z1 is connected to the source of the transistor Q1, the drain of the transistor Q1 is connected to the fourth resistor R4, one end of the fourth resistor R4 away from the drain of the transistor Q1 is grounded, and one end of the filter capacitor C1 away from the cathode of the first diode D1 is grounded.

[0056] Further, the cathode of the first lower bridge diode D3 is electrically connected to the anode of the first upper bridge diode D2, the cathode of the second lower bridge diode D5 is electrically connected to the anode of the second upper bridge diode D4, the cathode of the third lower bridge diode D7 is electrically connected to the anode of the third upper bridge diode D6, wherein the heliostat motor M is connected to the anode of the first upper bridge diode D2, the anode of the second upper bridge diode D4 is connected to the anode of the third upper bridge diode D6.

[0057] Furthermore, the grounded end of the filter capacitor C1 is also electrically connected to the positive poles of the first lower bridge diode D3, the second lower bridge diode D5 and the third lower bridge diode D7, and the grounded end of the filter capacitor C1 is electrically connected to the negative poles of the first upper bridge diode D2, the second upper bridge diode D4 and the third upper bridge diode D6.

[0058] Specifically, when a "48V" DC power supply is input, a current (for example, "1A") flows through the first diode D1 to make it forward-conducted (for example, the conduction voltage drop is "0.42V"), ​​and at the same time, the current flows forward through the first resistor R1 and the second resistor R2. Since the first resistor R1 and the second resistor R2 are connected in parallel with the first diode D1 and are clamped by the conduction voltage ("0.42V") of the first diode D1, the first resistor R1 and the second resistor R2 divide the voltage so that the G pole (gate) voltage of the transistor Q1 is slightly higher than the S pole (source) voltage. In one embodiment, it is specifically "0.34V" higher. At this time, the transistor Q1 is in the off state, and the DC input voltage supplies power to the motor control unit 13 of the subsequent stage, thereby controlling the heliostat motor M to run or stop.

[0059] Furthermore, when the heliostat motor M is in a power generation state, the motor winding freewheeling current will reversely charge the filter capacitor C1 through the first upper bridge diode D2, the second upper bridge diode D4 and the third upper bridge diode D6. When the voltage of the filter capacitor C1 is charged to a value higher than the DC input voltage (for example, to "51.2V"), ​​the first diode D1 is reversely cut off. At this time, the current will reversely flow into the input power supply through the first resistor R1 and the second resistor R2. When the voltage divider effect of the first resistor R1 and the second resistor R2 makes the G pole (gate) voltage of the transistor Q1 lower than the S pole (source) voltage, the voltage of the transistor Q1 is reversed. When the voltage of the filter capacitor C1 exceeds the turn-on threshold voltage of the transistor Q1, the SD of the transistor Q1 is turned on (the source and drain are turned on), wherein the turn-on threshold voltage can be taken as "-2.5V" in one embodiment. At this time, the voltage on the filter capacitor C1 and the back electromotive force voltage of the heliostat motor MM will be added to the fourth resistor R4 through the SD of the transistor Q1, and a current (greater than "1A") flows through the fourth resistor R4 to the ground terminal, and then returns to the motor winding through the first lower bridge diode D3, the second lower bridge diode D5 and the third lower bridge diode D7 to form a current closed loop to achieve a motor braking effect.

[0060] When the DC power input is short-circuited to the ground, the positive electrode of the first diode D1 is equivalent to being grounded. At this time, the subsequent circuit has no power supply. If the reflector is blown by strong wind and rotates, it will drive the motor to rotate through the transmission system. At this time, the back electromotive force generated by the rotation of the motor will reversely charge the filter capacitor C1 through the first upper bridge diode D2, the second upper bridge diode D4 and the third upper bridge diode D6 (for example, charged to "3.2" V). The first diode D1 is reversely cut off, and the current flows into the input power supply in the reverse direction through the first resistor R1 and the second resistor R2, that is, flows into the ground. When the voltage divider effect of the first resistor R1 and the second resistor R2 causes the transistor Q1 When the G pole (gate) voltage is lower than the S pole (source) voltage and exceeds the turn-on threshold voltage of the transistor Q1, the SD of the transistor Q1 is turned on. At this time, the voltage on the filter capacitor C1 and the back electromotive force voltage of the heliostat motor M will be added to the fourth resistor R4 through the SD of the transistor Q1. A current (specifically, the current is greater than "0.064A") flows through the fourth resistor R4 to the ground, and as the voltage on the filter capacitor C1 increases, the current flowing through becomes larger. Then, the current returns to the motor winding through the first lower bridge diode D3, the second lower bridge diode D5 and the third lower bridge diode D7 of the motor control unit 13 to form a current closed loop to achieve a motor braking effect.

[0061] When the DC power input wiring is open, there is no power input at this time, so the subsequent circuit has no power supply. If the reflector is blown by strong wind and rotates, it will drive the motor to rotate through the transmission system. At this time, the back electromotive force generated by the rotation of the motor will reversely charge the filter capacitor C1 through the first upper bridge diode D2, the second upper bridge diode D4 and the third upper bridge diode D6 of the controller (for example, charge to "8.5V"). The first diode D1 is reversely cut off, and the current will reversely flow to the ground through the first resistor R1, the second resistor R2 and the third resistor R3. When the voltage divider effect of the first resistor R1, the second resistor R2 and the third resistor R3 makes the transistor The G pole (gate) voltage of Q1 is lower than the S pole (source) voltage and exceeds the turn-on threshold voltage of the transistor Q1, and the SD of the transistor Q1 is turned on. At this time, the voltage on the filter capacitor C1 and the back electromotive force voltage of the heliostat motor M will be added to the fourth resistor R4 through the SD (source-drain channel) of the transistor Q1. A current (specifically greater than "0.17A") flows through the fourth resistor R4 to the ground, and as the voltage on the filter capacitor C1 increases, the current flowing through increases. Then, the current returns to the motor winding through the first lower bridge diode D3, the second lower bridge diode D5 and the third lower bridge diode D7 of the motor control unit 13 to form a current closed loop to achieve a motor braking effect.

[0062] When the positive and negative poles of the connector CN1 corresponding to the DC power input are connected reversely (for example, "48V+" is connected to pin 2 of CN1, and "48V-" is connected to pin 1 of CN1), the DC power supply "48V+" will flow into the cathode of the first diode D1 through the multiple switch tube diodes of the motor control unit 13. The first diode D1 is in a reverse cut-off state, and the current will flow reversely to "48V-" through the second diode Z1 and the second resistor R2. The second diode Z1 plays a voltage stabilizing role, which can protect the GS (gate and source) of the transistor Q1 from being damaged by overvoltage. At the same time, the second resistor R2 plays a current limiting role (specifically less than "6mA"), protecting the motor control unit 13 from damage.

[0063] It should be noted that, in the above embodiment, the value of the first resistor can be "20kΩ", the value of the second resistor can be "4.7kΩ", the value of the third resistor can be "43kΩ", and the value of the fourth resistor can be "50Ω".

[0064] Further, in one embodiment of the invention, if the current flowing through the first diode D1 is relatively large (for example, "4A"), the conduction voltage drop of the first diode D1 will increase, and the power will increase, so the heating temperature of the first diode D1 will also increase. In order to reduce the power and heating temperature of the first diode D1, therefore, in actual application, multiple first diodes can be connected in parallel to overcome the problems of heating and power increase, as shown in the following example. Figure 2As shown, the first diode D1 and the spare diodes D8, D9 and D10 are connected in parallel. Accordingly, for the application scenario based on the first diode D1 and the spare diodes D8, D9 and D10 being connected in parallel as described in this embodiment, the braking circuit unit 12 in the heliostat motor braking circuit 10 specifically includes the first diode D1 and the second diode Z1, the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4, and the transistor Q1, and the spare diodes D8, D9 and D10.

[0065] In summary, the present invention can produce a braking effect when the motor is in a power generation state during the normal operation control of the heliostat, and can also produce a braking effect when the DC input power supply is short-circuited or the input power supply wiring is open-circuited and fails, and can be compatible with the function of preventing the motor controller from being damaged when the positive and negative poles of the DC power supply input are reversed. The specific main features are: First, the motor controller does not need to install individual large and easily damaged relays, which is convenient for internal design of the motor, and the braking circuit can be placed outside the motor controller; second, when the motor controller controls the normal operation of the motor to stop, the motor has a braking effect when it is in a power generation state; third, when the external DC power supply of the motor controller is short-circuited, it has a motor braking effect; fourth, when the external DC power supply connection harness of the motor controller is open, it has a motor braking effect; fifth, when the positive and negative poles of the DC power supply input are reversed, it can prevent the motor controller from being damaged.

[0066] The descriptions of the processes or structures corresponding to the above-mentioned figures have different emphases. For parts that are not described in detail in a certain process or structure, please refer to the relevant descriptions of other processes or structures.

[0067] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A heliostat motor braking circuit, characterized in that: include: An input unit, including a DC power input; as well as a brake circuit unit electrically connected to the input unit, comprising a first diode and a second diode, a first resistor, a second resistor, a third resistor and a fourth resistor, and a transistor; as well as A motor control unit electrically connected to the brake circuit unit, comprising a filter capacitor, a first upper bridge diode, a second upper bridge diode and a third upper bridge diode, and a first lower bridge diode, a second lower bridge diode and a third lower bridge diode; as well as The output unit electrically connected to the motor control unit includes a heliostat motor.

2. The heliostat motor braking circuit according to claim 1, characterized in that: The first diode comprises a Schottky diode, the second diode comprises a Zener diode, and the transistor comprises a P-type MOS transistor.

3. The heliostat motor braking circuit according to claim 2, characterized in that: The first resistor, the second resistor and the third resistor are voltage-dividing resistors, and the fourth resistor is a braking resistor.

4. The heliostat motor braking circuit according to claim 3, characterized in that: The DC power input includes a power connector, wherein the positive electrode of the connector is connected to the positive electrode of the first diode, the second resistor and the third resistor, and the negative electrode of the connector is grounded.

5. The heliostat motor braking circuit according to claim 4, characterized in that: The cathode of the first diode is electrically connected to the first resistor, the second diode and the source of the transistor, and the end of the first resistor away from the cathode of the first diode is electrically connected to the anode of the second diode, the second resistor and the gate of the transistor, wherein the first resistor is connected in parallel with the second diode, the anode of the second diode is connected to the gate of the transistor, and the cathode of the second diode is connected to the source of the transistor.

6. The heliostat motor braking circuit according to claim 4, characterized in that: One end of the third resistor away from the positive electrode of the connector is grounded, the drain of the transistor is connected to the fourth resistor, and one end of the fourth resistor away from the drain of the transistor is grounded.

7. The heliostat motor braking circuit according to claim 4, characterized in that: The cathode of the first diode is electrically connected to one end of the filter capacitor, and is electrically connected to the cathode of the first upper bridge diode, the cathode of the second upper bridge diode, and the cathode of the third upper bridge diode.

8. The heliostat motor braking circuit according to claim 7, characterized in that: One end of the filter capacitor away from the cathode of the first diode is electrically connected to the anode of the first lower bridge diode, the anode of the second lower bridge diode and the anode of the third lower bridge diode.

9. The heliostat motor braking circuit according to claim 8, characterized in that: The cathode of the first lower bridge diode is electrically connected to the anode of the first upper bridge diode, the cathode of the second lower bridge diode is electrically connected to the anode of the second upper bridge diode, and the cathode of the third lower bridge diode is electrically connected to the anode of the third upper bridge diode.

10. The heliostat motor braking circuit according to claim 9, characterized in that: The anode of the first upper bridge diode, the anode of the second upper bridge diode, and the anode of the third upper bridge diode are all electrically connected to the heliostat motor.

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