Brushless motor electromagnetic brake drive circuit

Abstract

The utility model provides a brushless motor electromagnetic brake drive circuit, and relates to the technical field of electronic circuits. Comprising a first optocoupler, the input end of which is connected with a brake control signal; the isolation amplification driving circuit is connected with the output end of the first optocoupler; the electromagnetic brake is connected with the isolation amplification driving circuit; the over-current protector and the emergency stop switch are connected with the electromagnetic brake so as to control the electromagnetic brake to stop suddenly; and the emergency stop switch state detection circuit is used for detecting whether at least one of the emergency stop switch and the overcurrent protector is switched off. On-off control over the electromagnetic brake is achieved under the isolation condition, whether an emergency stop switch is switched off or not can be detected, a brushless motor driver executes processing such as shutdown in the first time of band-type brake braking, the overall equipment reliability is improved, and the circuit is good in performance in practical application.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a drive circuit for an electromagnetic brake of a brushless motor. Background Technology

[0002] Electromagnetic brakes are widely used in applications requiring high safety. When the power is disconnected, the electromagnetic brake engages, preventing the brushless motor from running. An emergency stop switch is typically connected in series with the electromagnetic brake coil; pressing the switch in an emergency disconnects the connection, achieving braking. However, in this situation, the brushless motor driver remains running, causing the motor rotor to stall and resulting in abnormal overcurrent and other adverse effects. Utility Model Content

[0003] This application provides a drive circuit for an electromagnetic brake of a brushless motor, which at least solves the above-mentioned technical problems existing in the prior art.

[0004] According to a first aspect of this application, a brushless motor electromagnetic brake drive circuit is provided, comprising:

[0005] The first optocoupler has its input terminal connected to the braking control signal;

[0006] An isolation amplifier driving circuit is connected to the output terminal of the first optocoupler;

[0007] An electromagnetic brake is connected to the isolation amplification drive circuit;

[0008] The isolation amplification drive circuit has a first working state and a second working state according to the braking control signal at the input terminal of the first optocoupler; in the first working state, the isolation amplification drive circuit outputs a drive signal to drive the electromagnetic brake to cancel the brake holding; in the second working state, the isolation amplification drive circuit de-energizes the electromagnetic brake and brakes the brake holding.

[0009] An overcurrent protector and an emergency stop switch are connected to the electromagnetic brake to control the emergency stop of the electromagnetic brake;

[0010] An emergency stop switch status detection circuit is used to detect whether at least one of the emergency stop switch and overcurrent protector is open.

[0011] In some embodiments of the first aspect of this application, the isolation amplification driving circuit includes a first field-effect transistor and a second field-effect transistor. The gate of the first field-effect transistor is connected to the output terminal of the first optocoupler, the source of the first field-effect transistor is connected to the positive terminal of the isolation power supply, the drain of the first field-effect transistor is connected to the gate of the second field-effect transistor, the source of the second field-effect transistor is connected to the negative terminal of the isolation power supply, and the drain of the second field-effect transistor is connected to an electromagnetic brake.

[0012] In some embodiments of the first aspect of this application, the gate of the first field-effect transistor is provided with a first current-limiting voltage divider circuit. The first current-limiting voltage divider circuit includes a second resistor and a third resistor. The first end of the second resistor and the first end of the third resistor are connected to the gate of the first field-effect transistor. The second end of the second resistor is connected to the output terminal of the first optocoupler. The second end of the third resistor is connected to the positive terminal of the isolation power supply.

[0013] In some embodiments of the first aspect of this application, the gate of the second field-effect transistor is provided with a second current-limiting voltage divider circuit. The second current-limiting voltage divider circuit includes a fourth resistor and a fifth resistor. The first end of the fourth resistor and the first end of the fifth resistor are connected to the gate of the second field-effect transistor. The second end of the fourth resistor is connected to the drain of the first field-effect transistor. The second end of the fifth resistor is connected to the negative terminal of the isolation power supply.

[0014] In some embodiments of the first aspect of this application, the electromagnetic brake is provided with a freewheeling diode in parallel.

[0015] In some embodiments of the first aspect of this application, the first end of the overcurrent protector is connected to the positive terminal of the isolation power supply, the second end of the overcurrent protector is connected to one end of the emergency stop switch, and the other end of the emergency stop switch is connected to the electromagnetic brake.

[0016] In some embodiments of the first aspect of this application, the emergency stop switch status detection circuit includes a sixth resistor, a second optocoupler, and a seventh resistor; the first end of the sixth resistor is connected to the emergency stop switch, and the second end of the sixth resistor is connected to the input end of the second optocoupler; the output end of the second optocoupler is connected to the first end of the seventh resistor and outputs an emergency stop switch status signal; the second end of the seventh resistor is connected to the positive terminal of the non-isolated power supply.

[0017] Compared with the prior art, this application has the following advantages:

[0018] This application enables on / off control of the electromagnetic brake in isolated conditions and can detect whether the emergency stop switch is open, allowing the brushless motor driver to perform shutdown and other processes in the first moment of brake application, thereby improving the overall equipment reliability. The circuit performs well in practical applications.

[0019] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0020] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of this application are illustrated in the drawings by way of example and not limitation, in which:

[0021] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0022] Figure 1 A circuit schematic diagram of an embodiment of this application is shown.

[0023] Figure 2 A specific circuit diagram of an embodiment of this application is shown. Detailed Implementation

[0024] To make the objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] Please refer to Figure 1 and Figure 2 This embodiment provides a brushless motor electromagnetic brake drive circuit, including:

[0026] The first optocoupler U1 has its input terminal connected to the braking control signal BRK_EN; the braking control signal BRK_EN is activated when it is low and activated when it is high.

[0027] Specifically, the first optocoupler U1 is preferably an EL817C, with its first and second pins being input terminals. The first pin is connected to the positive terminal of the non-isolated power supply +3.3V, and the second pin is connected to the braking control signal BRK_EN via the first resistor R1.

[0028] An isolation amplifier driving circuit is connected to the output terminal of the first optocoupler U1.

[0029] Specifically, the isolation amplifier driving circuit includes a first field-effect transistor Q1 and a second field-effect transistor Q2. The gate of the first field-effect transistor Q1 is connected to the output terminal of the first optocoupler U1, specifically pin 4 of the first optocoupler U1, while pin 3 of the first optocoupler U1 is grounded. The source of the first field-effect transistor Q1 is connected to the positive terminal E+24V of the isolation power supply, the drain of the first field-effect transistor Q1 is connected to the gate of the second field-effect transistor Q2, the source of the second field-effect transistor Q2 is connected to the negative terminal EGND of the isolation power supply, and the drain of the second field-effect transistor Q2 is connected to the electromagnetic brake. Preferably, the first field-effect transistor Q1 is an MMBT3906, and the second field-effect transistor Q2 is a D882.

[0030] The gate of the first field-effect transistor Q1 is provided with a first current-limiting voltage divider circuit. The first current-limiting voltage divider circuit includes a second resistor R2 and a third resistor R3. The first end of the second resistor R2 and the first end of the third resistor R3 are connected to the gate of the first field-effect transistor Q1. The second end of the second resistor R2 is connected to the output terminal of the first optocoupler U1. The second end of the third resistor R3 is connected to the positive terminal of the isolation power supply E+24V.

[0031] The gate of the second field-effect transistor Q2 is provided with a second current-limiting voltage divider circuit. The second current-limiting voltage divider circuit includes a fourth resistor R4 and a fifth resistor R5. The first end of the fourth resistor R4 and the first end of the fifth resistor R5 are connected to the gate of the second field-effect transistor Q2. The second end of the fourth resistor R4 is connected to the drain of the first field-effect transistor Q1. The second end of the fifth resistor R5 is connected to the negative terminal of the isolation power supply EGND.

[0032] Electromagnetic brake P2 is connected to the isolation amplification drive circuit. When the coil is de-energized, the brake stops the motor from running; when the coil is energized, the brake is released, allowing the motor to run. A freewheeling diode D1 is connected in parallel with electromagnetic brake P2. The coil of electromagnetic brake P2 is equivalent to an inductor, and a reverse current is generated when the power is off. This current is freewheeled through the freewheeling diode D1 to prevent overvoltage damage to other circuits.

[0033] The isolation amplifier drive circuit has a first working state and a second working state according to the braking control signal BRK_EN at the input terminal of the first optocoupler U1.

[0034] In the first operating state, the isolation amplifier drive circuit outputs a drive signal to drive the electromagnetic brake to release the brake. Specifically, the brake control signal BRK_EN is input at a low level (equivalent to GND). The +3.3V voltage passes through the internal LED of the first optocoupler U1 and then through the current-limiting resistor R1 to generate current. The fourth to third pins of the optocoupler output of the first optocoupler U1 are turned on. The positive terminal of the isolation power supply E+24V is divided and current-limited by the third resistor R3 and the second resistor R2, which turns on the first field-effect transistor Q1. The fourth resistor R4 and the fifth resistor R5 obtain the input voltage, which is divided and current-limited, turning on the second field-effect transistor Q2. The output drive signal drives the electromagnetic brake P2 to release the brake.

[0035] In the second operating state, the isolation amplifier drive circuit de-energizes the electromagnetic brake and initiates braking. Specifically, when the brake control signal BRK_EN is input at a high level (equivalent to +3.3V), the output pins 4 to 3 of the first optocoupler U1 are cut off, causing the first field-effect transistor Q1 and the second field-effect transistor Q2 to be cut off, thus de-energizing the electromagnetic brake P2 and initiating braking.

[0036] The overcurrent protector F1 and the emergency stop switch P1 are connected to the electromagnetic brake P2 to control the emergency stop of the electromagnetic brake.

[0037] The overcurrent protector F1 is an electromagnetic brake overcurrent protector, a self-resetting fuse used for overcurrent protection. It protects against short circuits caused by brake failure, preventing damage to other circuits. The emergency stop switch P1 is a normally closed switch; pressing it opens the switch to achieve emergency braking.

[0038] The first end of the overcurrent protector F1 is connected to the positive terminal of the isolation power supply E+24V, the second end of the overcurrent protector F1 is connected to one end (specifically the second pin) of the emergency stop switch P1, and the other end (specifically the first pin) of the emergency stop switch P1 is connected to the second pin of the electromagnetic brake.

[0039] An emergency stop switch status detection circuit is used to detect whether at least one of the emergency stop switch P1 and the overcurrent protector F1 is open.

[0040] The emergency stop switch P1 status detection circuit includes a sixth resistor R6, a second optocoupler, and a seventh resistor R7; the first end of the sixth resistor R6 is connected to the emergency stop switch P1, and the second end of the sixth resistor R6 is connected to the input end of the second optocoupler; the output end of the second optocoupler is connected to the first end of the seventh resistor R7 and outputs the emergency stop switch status signal SAFE_OUT; the second end of the seventh resistor R7 is connected to the positive terminal of the non-isolated power supply +3.3V.

[0041] When both the emergency stop switch P1 and the overcurrent protector F1 are on, the positive terminal E+24V of the isolation power supply flows through F1, P1, R6, and U2 to EGND, generating current. This causes pins 4 and 3 of the second optocoupler U2 to conduct, and the emergency stop switch status signal SAFE_OUT outputs a low level. When either the emergency stop switch P1 or the overcurrent protector F1 is off, pins 4 and 3 of the second optocoupler U2 are off, and +3.3V flows through R7 to output a high level to the emergency stop switch status signal SAFE_OUT.

[0042] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this application can be achieved, and this is not limited herein.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0044] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A brushless motor electromagnetic brake drive circuit, characterized by, include: The first optocoupler has its input terminal connected to the braking control signal; An isolation amplifier driving circuit is connected to the output terminal of the first optocoupler; An electromagnetic brake is connected to the isolation amplification drive circuit; The isolation amplification drive circuit has a first working state and a second working state according to the braking control signal at the input terminal of the first optocoupler; in the first working state, the isolation amplification drive circuit outputs a drive signal to drive the electromagnetic brake to cancel the brake holding; in the second working state, the isolation amplification drive circuit de-energizes the electromagnetic brake and brakes the brake holding. An overcurrent protector and an emergency stop switch are connected to the electromagnetic brake to control the emergency stop of the electromagnetic brake; An emergency stop switch status detection circuit is used to detect whether at least one of the emergency stop switch and overcurrent protector is open.

2. A drive circuit for a brushless electromagnetic brake according to claim 1, wherein The isolation amplifier driving circuit includes a first field-effect transistor and a second field-effect transistor. The gate of the first field-effect transistor is connected to the output terminal of the first optocoupler, the source of the first field-effect transistor is connected to the positive terminal of the isolation power supply, the drain of the first field-effect transistor is connected to the gate of the second field-effect transistor, the source of the second field-effect transistor is connected to the negative terminal of the isolation power supply, and the drain of the second field-effect transistor is connected to the electromagnetic brake.

3. A drive circuit for a brushless electromagnetic brake according to claim 2, wherein The gate of the first field-effect transistor is provided with a first current-limiting voltage divider circuit. The first current-limiting voltage divider circuit includes a second resistor and a third resistor. The first end of the second resistor and the first end of the third resistor are connected to the gate of the first field-effect transistor. The second end of the second resistor is connected to the output terminal of the first optocoupler. The second end of the third resistor is connected to the positive terminal of the isolation power supply.

4. A drive circuit for a brushless electromagnetic brake according to claim 2 or 3, wherein The gate of the second field-effect transistor is provided with a second current-limiting voltage divider circuit. The second current-limiting voltage divider circuit includes a fourth resistor and a fifth resistor. The first end of the fourth resistor and the first end of the fifth resistor are connected to the gate of the second field-effect transistor. The second end of the fourth resistor is connected to the drain of the first field-effect transistor. The second end of the fifth resistor is connected to the negative terminal of the isolation power supply.

5. A drive circuit for a brushless electromagnetic brake as defined in claim 1, wherein The electromagnetic brake is equipped with a freewheeling diode connected in parallel.

6. A drive circuit for a brushless electromagnetic brake as defined in claim 1, wherein The first end of the overcurrent protector is connected to the positive terminal of the isolation power supply, the second end of the overcurrent protector is connected to one end of the emergency stop switch, and the other end of the emergency stop switch is connected to the electromagnetic brake.

7. A drive circuit for a brushless electromagnetic brake as defined in claim 1, wherein The emergency stop switch status detection circuit includes a sixth resistor, a second optocoupler, and a seventh resistor; the first end of the sixth resistor is connected to the emergency stop switch, and the second end of the sixth resistor is connected to the input end of the second optocoupler; the output end of the second optocoupler is connected to the first end of the seventh resistor and outputs an emergency stop switch status signal; the second end of the seventh resistor is connected to the positive terminal of the non-isolated power supply.

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