Encoder power supply circuit, power supply method, and automation control system

Abstract

The application discloses an encoder power supply circuit, a power supply method and an automatic control system, and relates to the technical field of industrial automation. The encoder power supply circuit is located in an automatic control system formed by a servo driver, a cable and a servo motor, the cable is used for connecting the servo driver and the servo motor, and the encoder power supply circuit comprises a laser device, a fiber and a photoelectric converter. The laser device is arranged in the servo driver and is used for emitting laser light through a driving current provided by a driving circuit; the fiber is arranged in the cable and is used for transmitting the laser light into the servo motor; the photoelectric converter is arranged in the servo motor and is used for receiving the laser light and converting the laser light into direct-current electric energy; a voltage stabilizer is directly connected with an output end of the photoelectric converter, is used for stabilizing and regulating the direct-current electric energy, and outputs a constant power supply voltage; and an encoder is connected with the output end of the voltage stabilizer and is used for taking the constant power supply voltage as a working power supply. In this way, the power supply for the encoder can avoid voltage drop caused by copper cable transmission.

Description

Technical Field

[0001] This application relates to the field of industrial automation technology, and more specifically, to encoder power supply circuits, power supply methods, and automated control systems. Background Technology

[0002] In automated control systems, servo motors are used to achieve precise position and speed control, and encoders are often installed in the cavity behind their covers. The encoders provide real-time feedback to the servo driver on the motor's rotor position, speed, and magnetic pole phase information, forming a closed-loop control system. The encoder's power supply is provided by the servo driver's internal power circuit and is typically transmitted to the encoder at the motor end via copper cables.

[0003] However, as the wiring distance between the servo driver and the servo motor increases, the resistance of the copper cable itself causes a significant voltage drop, resulting in the actual power supply voltage at the encoder end being lower than the rated value. This leads to problems such as encoder malfunction, signal transmission errors, and even position data loss. Furthermore, due to the limited space in the servo motor's rear cover cavity, it is necessary to simplify the encoder's power supply circuit components and structure for installation within the rear cover cavity.

[0004] Therefore, how to avoid voltage drop in encoder lines over long distances while designing a simplified power supply circuit has become an urgent problem to be solved. Summary of the Invention

[0005] This application provides an encoder power supply circuit, power supply method, and automatic control system. Based on optical fiber transmission of optical energy, it solves the voltage drop problem of existing copper cable power supply and the technical problems of existing optical fiber power supply solutions being bulky, expensive, and unsuitable for confined spaces through extremely simplified circuit design tailored to the encoder load characteristics. The specific technical solution is as follows.

[0006] In a first aspect, an encoder power supply circuit is provided. This encoder power supply circuit is located in an automated control system consisting of a servo driver, cables, and a servo motor. The cables connect the servo driver and the servo motor. The encoder power supply circuit includes: a laser, disposed in the servo driver, used to emit laser light through a drive current provided by the drive circuit; an optical fiber, disposed in the cable, used to transmit the laser light to the servo motor; a photoelectric converter, disposed in the servo motor, used to receive the laser light and convert it into DC power; a voltage regulator, the input terminal of which is directly connected to the output terminal of the photoelectric converter, used to regulate and condition the DC power to output a constant supply voltage; and an encoder, connected to the output terminal of the voltage regulator, used to use the constant supply voltage as its operating power source.

[0007] In conjunction with the first aspect, the photoelectric converter is a gallium arsenide photovoltaic cell used to receive laser light and convert it into a first DC voltage.

[0008] In conjunction with the first aspect, the input pin of the voltage regulator is directly connected to the output terminal of the photoelectric converter, inputting the first DC voltage into the voltage regulator and outputting the supply voltage.

[0009] In conjunction with the first aspect, the voltage regulator is a low-dropout linear regulator (LDO), the first DC voltage is greater than the supply voltage, and the rated power consumption of the encoder is lower than the optical power of the laser, so that the voltage regulator can maintain the stability of the supply voltage.

[0010] In conjunction with the first aspect, the driving circuit includes a DC power supply and a current-limiting resistor. The laser is connected to the DC power supply after being connected in series with the current-limiting resistor. The driving current of the laser is adjusted by setting the resistance value of the current-limiting resistor in order to maintain a stable output optical power of the laser.

[0011] In conjunction with the first aspect, the cable is a hybrid optical-electric cable, which also includes the encoder's signal transmission line. The optical fiber and the signal transmission line are integrated into the same cable, and the cable is wrapped with an outer sheath.

[0012] In conjunction with the first aspect, the photoelectric converter and the voltage regulator are integrated on the same printed circuit board, and the printed circuit board and the encoder are jointly housed in the rear cover cavity of the servo motor.

[0013] In conjunction with the first aspect, it also includes a voltage detection circuit, which is used to collect the input voltage information of the voltage regulator and transmit the voltage information back to the servo driver via a multiplexed signal transmission line; the servo driver is used to adjust the drive current according to the voltage information.

[0014] It should be noted that, in the absence of conflict, the features in the various embodiments of the first aspect can be combined with each other, and any combination of features in different embodiments is also within the protection scope of this application. That is to say, the various embodiments described above can also be arbitrarily combined according to actual needs.

[0015] Secondly, an encoder power supply method is provided, applied to an encoder power supply circuit. The encoder power supply circuit includes a laser, an optical fiber, a photoelectric converter, a voltage regulator, and an encoder. The optical fiber connects the laser and the input end of the photoelectric converter, and the voltage regulator connects the output end of the photoelectric converter and the encoder. The method includes: the laser receiving the driving current provided by the driving circuit and emitting laser light with stable optical power; the optical fiber transmitting the laser light to the photoelectric converter; the photoelectric converter converting the received laser light into DC power; the voltage regulator regulating the DC power to obtain a constant supply voltage; and the encoder using the constant supply voltage as its operating power to support stable encoder operation.

[0016] Thirdly, an automated control system is provided, including a servo driver, cables, a servo motor, and an encoder power supply circuit of any one of the first aspects.

[0017] Compared to the direct DC power transmission via copper cables used in encoders of servo motors, the device in this application first utilizes a drive circuit to provide drive current, enabling a laser to emit stable optical power. The laser is then transmitted via optical fiber to a photoelectric converter, which converts it into DC power. A voltage regulator then regulates this DC power to output a constant supply voltage, which is finally input to the encoder as its operating power. This solution, by using optical fiber instead of copper cables for energy transmission and employing a voltage regulator for linear voltage regulation at the end, eliminates the resistive voltage drop of copper cables, decoupling the encoder supply voltage from the transmission distance and maintaining the nominal value even over long distances. Furthermore, the DC voltage output from the photovoltaic cell is directly stepped down and regulated with high precision by the voltage regulator, which maintains a constant supply voltage without the need for a transformer or energy storage capacitor at the input. Therefore, the encoder power supply circuit in the servo motor only requires a photoelectric converter and a voltage regulator, which can be directly installed within the rear cover cavity of the servo motor, making it particularly suitable for encoder power supply scenarios involving long distances and confined spaces. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of powering the encoder via copper cable in an existing automated control system; Figure 2 This is a schematic block diagram of the encoder power supply circuit provided in the embodiments of this application; Figure 3 This is a schematic diagram of the laser driving circuit provided in an embodiment of this application; Figure 4 This is a schematic diagram of the cross-sectional structure of the optoelectronic hybrid cable provided in the embodiments of this application; Figure 5 This is a schematic diagram of the encoder terminal circuit provided in this application embodiment being installed inside the motor rear cover; Figure 6 This is a schematic diagram of the encoder-side photoelectric conversion and voltage regulation circuit provided in the embodiments of this application; Figure 7 This is a schematic flowchart of the encoder power supply method provided in the embodiments of this application; Figure 8 This is a schematic diagram comparing encoder voltages supplied by the encoder power supply circuit and the copper cable power supply according to embodiments of this application; Figure 9This is a schematic diagram of an automated control system including an encoder power supply circuit, provided in an embodiment of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0021] Example 1: Encoder power supply circuit.

[0022] Figure 1 This is a schematic diagram of an existing automated control system that supplies power to the encoder via copper cables. For example... Figure 1 As shown, in the prior art, the servo driver provides DC power to the encoder at the tail of the servo motor via a copper cable. Due to the resistance of the wires in the copper cable, a voltage drop will occur when current passes through it. Especially when the servo driver and the servo motor are far apart (e.g., tens of meters apart), the DC power will travel a long distance through the copper cable, causing the actual voltage received at the encoder to deviate from the nominal voltage at the driver, thus affecting the normal operation of the encoder.

[0023] Figure 2 This is a schematic block diagram of the encoder power supply circuit provided in an embodiment of this application. Figure 2 As shown in the embodiment of this application, the encoder power supply circuit is located in an automated control system. The automated control system includes a servo driver 1, a servo motor 2, and a cable 3. The encoder power supply circuit mainly consists of a drive circuit 11, a laser 12, an optical fiber 31, a photoelectric converter 21, a voltage regulator 22, and an encoder 23. Specifically, the laser 12 and its drive circuit 11 are located in the servo driver 1; the photoelectric converter 21, the voltage regulator 22, and the encoder 23 are located in the servo motor 2, typically within the rear cover cavity of the servo motor 2; the output of the voltage regulator 22 is connected to the power pin of the encoder 23; the cable 3 connects the servo driver 1 and the servo motor 2, and the optical fiber 31 is located in the cable 3, connecting the laser 12 and the photoelectric converter 21.

[0024] In this embodiment, the driving circuit 11 is configured to provide a constant driving current to the laser 12, so that the laser 12 emits laser light with stable power. The laser 12 may be a semiconductor laser diode (LD) with a rated wavelength and a large output power (e.g., 2W).

[0025] In this embodiment, the optical fiber 31 is a single-mode or multi-mode optical fiber, with its input end aligned with the output port of the laser 12, and the other end connected to the photoelectric converter 21. In this embodiment, the distance between the servo driver 1 and the servo motor 2 is on the order of tens of meters. The laser attenuation transmitted by the optical fiber 31 over this distance is negligible. Therefore, the photoelectric converter 21 can effectively receive all the optical power emitted by the laser 12.

[0026] In this embodiment, the photoelectric converter 21 is used to convert laser light into direct current (DC) power, i.e., a first DC voltage. For example, the photoelectric converter 21 can be a gallium arsenide (GaAs) photovoltaic cell module, which generates DC power through the photovoltaic effect after receiving laser light. When the laser power is matched to the load, the first DC voltage generated at the output of the photoelectric converter 21 can be stabilized between 6V and 7V, and this first DC voltage is directly connected to the input of the voltage regulator 22.

[0027] In this embodiment, the voltage regulator 22 is used to regulate and standardize the DC power (i.e., the first DC voltage) to output a constant supply voltage as the power supply for the encoder. For example, the voltage regulator 22 can be a low dropout regulator (LDO), which has a small output voltage drop (e.g., 0.3V) and power ripple suppression. The encoder's power supply is typically 5V or 3.3V. Since the first DC voltage (6V to 7V) input to the LDO is higher than the required input voltage (the sum of the regulator 22's output voltage and the output voltage drop; for example, when the encoder's power supply is 5V and the output voltage drop is 0.3V, the LDO requires an input voltage of 5.3V), the LDO can effectively regulate the first DC voltage and output a stable voltage required by the encoder.

[0028] It should be noted that in the prior art, the photoelectric converter 21 and the voltage regulator 22 are often connected through a boost converter and an energy storage capacitor. However, in this embodiment, the output terminal of the photoelectric converter 21 and the input terminal of the voltage regulator 22 are directly connected, mainly based on the following premises: First, the laser 12 is driven by a stable DC power supply and a current-limiting resistor, and the output optical power is highly stable, ensuring that the first DC voltage output by the photoelectric converter 21 is relatively constant and will not fluctuate drastically; Second, the total power consumption of the encoder 23 is usually less than 1W, and the steady-state operating current is small and changes slowly. The fast loop response of the voltage regulator 22 itself can suppress voltage fluctuations, and there is no need for an external energy storage capacitor to provide transient current; Finally, the encoder 23 is installed in the narrow cavity of the servo motor 2's rear cover, and conventional energy storage capacitors are difficult or impossible to fit into the cavity due to their large size. Therefore, omitting the energy storage capacitor is not only feasible but also necessary for space installation.

[0029] Figure 3 This is a schematic diagram of the laser driving circuit provided in an embodiment of this application. Figure 3 As shown, the DC power supply (V1) inside the drive circuit 11 is connected to the anode of the laser 12 (such as a laser diode LD) through a current-limiting resistor (R1), and the cathode of the laser 12 is grounded. Considering that the on-resistance of the laser 12 is small and negligible, the corresponding drive current (if) of the laser 12 can be calculated according to the formula: if = V1 / R1. Wherein, under the premise that the DC power supply remains stable, keeping the current-limiting resistor constant will enable the laser 12 to emit laser light with stable power. In this embodiment, the output power of the laser 12 is approximately 2W, and the drive circuit 11 achieves constant current drive through the current-limiting resistor. To ensure stability, an optional filter composed of a small resistor and capacitor can also be added between the DC power supply and the current-limiting resistor.

[0030] In some implementations, the current-limiting resistor can be adjusted according to the input current of the encoder 23 to change the driving current entering the laser 12, thereby dynamically adjusting the output optical power of the laser 12 to match the changing operating power of the encoder 23.

[0031] Figure 4 This is a schematic diagram of the cross-sectional structure of the optoelectronic hybrid cable provided in an embodiment of this application. Figure 4 As shown, in this embodiment, the optical fiber and signal transmission line can be integrated in parallel within the same cable, with the cable 3 encased in an outer sheath 33. For example, the optical fiber 31 is a tightly packed optical fiber, which may have a protective layer 311. The optical fiber 31 and the encoder's signal transmission line 32 are both encased within the outer sheath 33, forming a hybrid cable 3. The cable 3 is a hybrid optoelectronic cable, serving both power supply and signal transmission functions. In the servo driver, the optical fiber 31 is connected to the laser; in the servo motor, the optical fiber 31 is connected to the optoelectronic converter module via an optical fiber connector, while the signal transmission line 32 is connected to the encoder's signal terminal.

[0032] In this embodiment, the optical fiber 31 and the signal transmission line 32 can be integrated into the same hybrid cable by twisting or parallel sharing a common sheath. This embodiment does not limit the specific integration method of the optical fiber 31 and the signal transmission line 32.

[0033] Figure 5 This is a schematic diagram showing the installation of the encoder terminal circuit provided in this application within the motor rear cover. (See attached diagram.) Figure 5As shown, the rear cover cavity 20 is visible after removing the rear cover of the servo motor 2. The rear cover cavity 20 has a relatively compact space, with a diameter (D) typically between 40 and 60 mm and a depth (L) typically between 15 and 18 mm. To accommodate this narrow space, the photoelectric converter and voltage regulator are preferably surface-mount packaged components and integrated into the same printed circuit board (PCB), which is integrated with the encoder within the rear cover cavity 20. The diameter of this PCB is smaller than the inner diameter of the rear cover cavity 20, and it is fixed to the inner wall of the cavity by screws or thermally conductive silicone. The optical fiber is connected to the rear cover cavity 20 through an optical fiber connector, with its output end facing the light-receiving surface of the photoelectric converter, ensuring efficient coupling of optical energy. In this way, the encoder power supply function can be integrated within the rear cover cavity 20 using the above structure.

[0034] Figure 6 This is a schematic diagram of the encoder-side photoelectric conversion and voltage regulation circuit provided in an embodiment of this application. Figure 6 As shown, the positive terminal of the photoelectric converter 21 is connected to the input pin (IN pin) of the voltage regulator 22, the output pin (OUT pin) of the voltage regulator 22 outputs the supply voltage (Vdd), and the ground pin (GND pin) of the voltage regulator 22 is grounded. The supply voltage Vdd is sent to the power supply terminal of the encoder 23 through the signal cable. It can be seen that there is no boost converter or energy storage capacitor between the photoelectric converter 21 and the voltage regulator 22, achieving a simplified power supply architecture. In some embodiments, the IN pin can also be connected to ground with a first capacitor (C1) to filter high-frequency noise, and the OUT pin can also be connected to ground with a second capacitor (C2) for loop stabilization and transient response.

[0035] In some implementations, to further ensure the long-term power supply reliability of the encoder power supply circuit in industrial environments (such as large temperature differences between day and night and long-term operation of equipment), this application integrates a closed-loop feedback regulation mechanism into the aforementioned optoelectronic power supply architecture.

[0036] Specifically, in this embodiment, a voltage detection circuit is also provided at the servo motor 2. This voltage detection circuit can be configured to acquire the input voltage (i.e., the first DC voltage) of the voltage regulator 22 in real time. Under the premise of miniaturization design, the voltage detection circuit preferably reuses the internal resources of the encoder 23. For example, the analog-to-digital converter (ADC) integrated on the microcontroller in the encoder 23 can be used to detect the voltage information at the front end of the voltage regulator in real time. When transmitting the detection data of the servo motor 2, the encoder 23 can add the above voltage information as additional data to the detection data and reuse the original signal transmission line 32 to send it back to the servo driver 1.

[0037] In the servo driver 1, its internal control unit extracts voltage information while parsing the detection data. The control unit compares this voltage information with a preset reference value, and when a voltage deviation is detected, it can generate an adjustment command to the drive circuit 11. For example, by setting the resistance value of the current-limiting resistor, it adjusts the drive current of the laser 12 to maintain stable output optical power of the laser 12. The adjustment command can also instruct the replacement of the DC power supply to adjust the drive current of the laser 12.

[0038] For example, when the control unit in the servo driver 1 determines that the first DC voltage is decreasing due to temperature rise or device aging, it can increase the drive current to improve the optical power of the laser 12, so that the output voltage of the remote photoelectric converter 21 can be restored to the target range; otherwise, the drive current can be reduced, so that the encoder power supply circuit has the ability to adapt to environmental changes, which is suitable for high-precision long-stroke automation scenarios.

[0039] Example 2: Implementation method of power supply for encoder power circuit.

[0040] Figure 7 This is a schematic flowchart of the encoder power supply method provided in an embodiment of this application. Figure 7 As shown, this application provides an encoder power supply method, the specific process of which is as follows.

[0041] S1. The laser receives the driving current provided by the driving circuit and emits laser light with stable optical power.

[0042] In this embodiment, the laser is a semiconductor laser diode, installed inside the servo driver. The driving circuit consists of a DC power supply and a current-limiting resistor, with the laser connected in series with the current-limiting resistor and then connected to the DC power supply. The DC power supply is typically provided by the driving circuit, and the resistance value of the current-limiting resistor is set according to the required driving current of the laser. By maintaining the stability of the DC power supply voltage and the resistance value of the current-limiting resistor, the driving current can be kept constant, thereby enabling the laser to output a stable optical power. The rated optical power of the laser is selected based on the actual power consumption of the encoder, generally between 1.5W and 3W, meeting the power consumption requirements of commonly used encoders that are less than 1W. The driving circuit can consist only of a DC power supply and resistive elements, resulting in a simple structure, high reliability, and suitability for miniaturized applications.

[0043] S2. The optical fiber transmits the laser to the photoelectric converter.

[0044] In this embodiment, the optical fiber is arranged in the cable connecting the servo driver and the servo motor. The optical fiber can be multimode or single-mode, with multimode being preferred to balance cost and coupling efficiency. In actual wiring of automated control systems, when the cable length is within 100 meters, the transmission loss of the optical fiber is extremely low, and the power attenuation of the laser is negligible. The optical fiber can be integrated with the encoder's signal transmission line (usually copper cable), using a twisted or parallel common sheath method to form a single hybrid cable. This achieves both optical power transmission and signal return functionality without occupying additional wiring space.

[0045] S3. The photoelectric converter converts the received laser light into DC power.

[0046] In this embodiment, the photoelectric converter uses a gallium arsenide (GaAs) photovoltaic cell, which is deployed inside the servo motor. When irradiated by a laser, the GaAs photovoltaic cell directly converts light energy into DC power through the photovoltaic effect. Under stable laser power conditions, when the laser power matches the load, the first DC voltage generated at the output of the photoelectric converter can be stabilized between 6V and 7V. The output of the photoelectric converter is directly connected to the input of the subsequent voltage regulator; no energy storage capacitor, inductor, or DC-DC converter is placed between them, thereby reducing the number and size of components and meeting the limited space requirements within the servo motor's rear cover cavity.

[0047] S4. The voltage regulator regulates and stabilizes the DC power to obtain a constant supply voltage.

[0048] In this embodiment, the voltage regulator is a low-dropout linear regulator (LDO), whose input pin is directly connected to the output of the photoelectric converter. The input voltage (first DC voltage) of the LDO is greater than its output voltage (supply voltage). The input voltage of the LDO is the first DC voltage, and the output voltage of the LDO can be fixed at 5V or 3.3V according to the encoder requirements, or it can be set to the required voltage through an external feedback resistor. Since the rated power consumption of the encoder is usually less than 1W, and the input optical power (1.5W to 3W) has sufficient margin, even when the encoder 23 load fluctuates instantaneously, the LDO can maintain a constant output voltage for a short time. Therefore, there is no need to connect a large-capacity energy storage capacitor in parallel at the input terminal to continuously output a constant supply voltage. For example, when the encoder load current changes instantaneously, the small fluctuation of the input voltage will be absorbed and suppressed by the LDO, ensuring that the output voltage ripple is minimal and the stability is high.

[0049] The S5 encoder uses a constant supply voltage as its operating power source for stable operation.

[0050] In this embodiment, the encoder is housed within the rear cover cavity of the servo motor, and its power supply terminal is connected to the output terminal of the LDO, using a constant supply voltage as its operating power. After power-on, the encoder acquires and processes signals such as motor rotor position, speed, and magnetic pole phase. The processed data is transmitted back to the servo driver as digital signals via copper signal lines. Since digital signals have a certain tolerance for level fluctuations, voltage drops on the transmission path do not cause data errors. Therefore, the entire system only needs to employ a fiber optic transmission scheme in the encoder power supply to completely avoid voltage drop issues caused by long-distance copper cable power supply. With a stable supply voltage, the encoder operates stably, preventing communication anomalies or position data loss due to undervoltage.

[0051] In some embodiments, the encoder power supply method provided in this application further includes a feedback regulation stage, whereby the servo driver adjusts the laser drive current in a closed loop based on the returned voltage information. Specifically, a voltage detection circuit located at the servo motor end collects the input voltage of the voltage regulator in real time. This voltage information is encoded into a digital signal by the encoder and transmitted back to the servo driver via a multiplexed signal transmission line. The controller in the servo driver analyzes this voltage information in real time and compares it with a preset voltage. When the input voltage deviates from the preset range, the controller adjusts the current-limiting resistor in the drive circuit to correspondingly increase or decrease the laser drive current, thereby dynamically maintaining the stability of the output power of the photoelectric converter. This step enables the system to have adaptive compensation functions for environmental temperature differences and device aging, further enhancing the operational stability of the encoder in long-distance power supply scenarios.

[0052] Based on the encoder power supply method shown in steps S1 to S5 above, this application utilizes laser as an energy carrier, transmits it through optical fiber, and then performs photoelectric conversion and low-dropout linear voltage regulation to ultimately provide a constant operating power supply for the encoder. The method provided by this application eliminates the impact of line voltage drop in the original copper cable power supply circuit on the encoder power supply quality, eliminates the need for complex boost and energy storage circuits, and improves the reliability and stability of encoder power supply under long-distance operating conditions while maintaining a simple system structure, low cost, and ease of installation.

[0053] Figure 8 This is a schematic diagram comparing encoder voltage supplied by the encoder power supply circuit and the copper cable power supply according to embodiments of this application. Figure 8 As shown, the horizontal axis represents the encoder power supply time, and the vertical axis represents the encoder power supply voltage. Taking a normal encoder power supply voltage of 5V as an example, in the power supply method provided in this application, the encoder power supply voltage can be maintained at the normal operating voltage for a long time, and the operating voltage is stable; in the existing power supply method using copper cables, the encoder power supply voltage fluctuates between 4V and 4.5V, and the fluctuation of the operating voltage is greater than that of the power supply method provided in this application. Figure 8It is evident that the power supply method provided in this application effectively improves the power supply quality to the encoder.

[0054] In some implementations, the encoder 23 operates at 3.3V, and the voltage regulator 22 can be optionally equipped with a 3.3V fixed-output LDO to adapt to the 3.3V powered encoder 23. At this time, the output voltage of the photovoltaic cell at 2W optical power remains 6V to 7V, meeting the input range of the LDO. With other connections unchanged, the effect remains stable.

[0055] Example 3: An automated control system including an encoder power supply circuit.

[0056] Figure 9 This is a schematic diagram of an automated control system including an encoder power supply circuit, provided in an embodiment of this application. Figure 9 As shown, the automated control system includes a servo driver, cables, a servo motor, and an encoder power supply circuit. The encoder power supply circuit has the circuit structure shown in Embodiment 1, and can implement the encoder power supply method shown in Embodiment 2.

[0057] In this embodiment, the servo driver is the control core of the automated control system, integrating a laser and drive circuit. The drive circuit consists of a DC power supply and a current-limiting resistor. By setting the resistance value of the current-limiting resistor, a constant drive current can be provided to the laser, enabling the laser to emit laser light with stable power that meets the encoder's power consumption requirements. The servo driver is also responsible for receiving and processing the digital signals fed back from the encoder, realizing closed-loop control of the motor.

[0058] The cable connects the servo drive and the servo motor, serving both energy and signal transmission purposes. Internally, the cable integrates both optical fiber and signal transmission lines. The optical fiber is preferably multimode fiber for low-loss laser energy transmission; the signal transmission line is typically copper cable (e.g., twisted-pair shielded cable) used to transmit digital signals such as position and speed acquired by the encoder back to the servo drive. The optical fiber and signal transmission line can be integrated into a single hybrid cable using twisting or parallel sharing of the same sheath. This simplifies on-site cabling and avoids occupying additional cable conduit space, meeting the requirements of industrial environments for compact and lightweight cabling.

[0059] The servo motor has a rear cover cavity at its tail end, with a relatively compact internal space. The encoder and its power supply circuit are installed in this rear cover cavity. Its core components include a photoelectric converter and a voltage regulator, which are optionally integrated on the same printed circuit board. The photoelectric converter and voltage regulator are preferably surface-mount packages with low component height, so that they can be installed together with the encoder body in the rear cover cavity to adapt to the narrow space. Specifically, the photoelectric converter is a gallium arsenide photovoltaic cell with its light-receiving surface facing the optical fiber output end. It directly converts the received laser light into a first DC voltage (e.g., 6V to 7V) through the photovoltaic effect. The voltage regulator is a low-dropout linear regulator, whose input end is directly connected to the output end of the photoelectric converter. It regulates and conditions the first DC voltage without the need for an energy storage capacitor, and outputs a stable supply voltage (e.g., 5V or 3.3V) to supply the encoder. After the encoder is powered on, it operates based on the stable supply voltage, samples the parameters of the motor rotor during operation, and generates digital signals. These digital signals are returned to the servo driver in real time via a signal transmission line, forming a fully closed-loop position feedback.

[0060] The automated control system provided in this embodiment replaces the traditional direct copper cable power supply method with an energy transmission path composed of a laser, optical fiber, and photoelectric converter, eliminating the voltage drop and power fluctuation problems caused by long-distance cabling. At transmission distances within 100 meters, the laser power attenuation in the optical fiber is minimal, resulting in almost no loss of light energy received by the photoelectric converter, thus ensuring a continuous and constant power supply voltage. Simultaneously, the encoder has low power consumption and a simplified power circuit structure, eliminating the need for bulky components such as energy storage capacitors and voltage converters, and fully utilizing the limited space of the servo motor's rear cover, achieving high integration and high reliability of the power supply system. This automated control system is particularly suitable for automated applications where the distance between the drive and motor is large, such as machine tool gantry cranes, automated warehouses, large production lines, and long-stroke gantry equipment.

[0061] Furthermore, as a system-level enhancement, the servo drive in this automated control system can also be configured with voltage closed-loop feedback regulation logic. During operation, the servo drive also synchronously reads the power supply voltage detection data collected by the encoder. The control algorithm built into the servo drive dynamically adjusts the emitted light power of the laser based on the detection data to stabilize the encoder's power supply voltage. Even when the cable is bent, in motion, or under significant ambient temperature fluctuations, the system can maintain a highly constant power supply voltage, achieving long-term adaptive and stable operation capabilities, making it particularly suitable for long-stroke industrial automation applications.

[0062] It should be noted that the above description is only one specific embodiment of this application and does not constitute a limitation on the scope of protection of this application. In specific implementation, the type and power of the laser, the specifications of the optical fiber, the selection of the photoelectric converter, and the output voltage of the LDO can all be adjusted according to the actual needs of the encoder. As long as the architecture of using optical fiber to transmit optical energy and using LDO for terminal voltage regulation is adopted, it falls within the protection concept of this application.

[0063] It is understood that the functional division between the modules illustrated in the embodiments of this application is merely illustrative and does not constitute a limitation on the function of the automation control system. In other embodiments of this application, the automation control system may also employ different modules or combinations of multiple modules to achieve the functions of the automation control system.

[0064] Those skilled in the art will understand that implementing all or part of the processes in the foregoing embodiments can be accomplished by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the foregoing method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as readable storage devices or random access memory, magnetic disks, or optical disks.

[0065] In summary, the above description is merely an embodiment of the technical solution of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made based on the disclosure of this application should be included within the scope of protection of this application.

Claims

1. An encoder power supply circuit, characterized in that, The encoder power supply circuit is located in an automated control system consisting of a servo driver, cables, and a servo motor. The cables are used to connect the servo driver and the servo motor. The encoder power supply circuit includes: The laser is located in the servo driver; A driving circuit is used to provide a constant DC driving current to the laser so that the laser outputs laser light with stable optical power. An optical fiber, disposed in the cable, is used to transmit the laser to the servo motor; A photoelectric converter is disposed in the rear cover cavity of the servo motor for receiving the laser and converting it into DC power. A voltage regulator is installed in the rear cover cavity of the servo motor. The input terminal of the voltage regulator is directly connected to the output terminal of the photoelectric converter. It is used to regulate the DC power and output a constant supply voltage. A voltage detection circuit is used to collect the input voltage information of the voltage regulator and transmit the voltage information back to the servo driver through a signal transmission line, instructing the servo driver to adjust the drive current according to the voltage information. An encoder is disposed in the rear cover cavity of the servo motor and connected to the output terminal of the voltage regulator. It is used to use the constant supply voltage as the working power source and, when generating the motor detection data, inserts the voltage information as additional data into the detection data so as to multiplex the signal transmission line and send it to the servo driver.

2. The encoder power supply circuit according to claim 1, characterized in that, The photoelectric converter is a gallium arsenide photovoltaic cell, used to receive the laser and convert the laser into a first DC voltage.

3. The encoder power supply circuit according to claim 2, characterized in that, The input pin of the voltage regulator is directly connected to the output terminal of the photoelectric converter, inputting the first DC voltage into the voltage regulator and outputting the supply voltage.

4. The encoder power supply circuit according to claim 3, characterized in that, The voltage regulator is a low-dropout linear regulator (LDO). The first DC voltage is greater than the supply voltage, and the rated power consumption of the encoder is lower than the optical power of the laser, so that the voltage regulator maintains the stability of the supply voltage.

5. The encoder power supply circuit according to claim 1, characterized in that, The driving circuit includes a DC power supply and a current-limiting resistor. The laser is connected to the DC power supply in series with the current-limiting resistor. The driving current of the laser is adjusted by setting the resistance value of the current-limiting resistor to maintain a stable output optical power of the laser.

6. The encoder power supply circuit according to claim 1, characterized in that, The cable is a hybrid optical-electric cable, in which the optical fiber and the signal transmission line are integrated into the same cable, and the cable is wrapped with an outer sheath.

7. The encoder power supply circuit according to any one of claims 1-6, characterized in that, The photoelectric converter and the voltage regulator are integrated on the same printed circuit board, and the printed circuit board and the encoder are jointly disposed in the rear cover cavity of the servo motor.

8. An encoder power supply method, characterized in that, The method is applied to an encoder power supply circuit, which includes a laser, an optical fiber, a photoelectric converter, a voltage regulator, a voltage detection circuit, and an encoder. The optical fiber connects the laser and the input terminal of the photoelectric converter, and the voltage regulator connects the output terminal of the photoelectric converter and the encoder. The laser receives the driving current provided by the driving circuit and emits laser light with stable optical power. The optical fiber transmits the laser to the photoelectric converter; The photoelectric converter converts the received laser light into direct current electrical energy; The voltage regulator regulates the DC power to obtain a constant supply voltage; The voltage detection circuit is used to collect the input voltage information of the voltage regulator and transmit the voltage information back to the servo driver through the signal transmission line, instructing the servo driver to adjust the drive current according to the voltage information. The encoder uses the constant supply voltage as its operating power to support stable operation. When generating motor detection data, the voltage information is inserted as additional data into the detection data to multiplex the signal transmission line and send it to the servo driver.

9. An automated control system, characterized in that, It includes a servo driver, cables, a servo motor, and an encoder power supply circuit as described in any one of claims 1-7.

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