Power supply circuit of the relay

Abstract

The present invention discloses a power supply circuit for a relay, specifically including: a switch unit with its first end connected to the first output end of a power battery pack; a DC / DC controller with its input end connected to the second end of the switch unit, and the output end of the DC / DC controller is connected to the electrode of a first relay installed at the second output end of the power battery pack; the power battery pack, the switch unit, the DC / DC controller and the first relay are connected in sequence to supply power to the first relay. The present invention uses the DC / DC controller to adjust the output current of the power battery pack to supply power to the first relay instead of a lead-acid battery. Since the DC / DC controller has the characteristic of being able to stably and continuously output voltage and current, it can stably and continuously supply power to the first relay, solving the problem that the first relay cannot be attracted due to unstable power supply of the lead-acid battery, and ensuring the normal operation of the first relay.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit design, and particularly to a power supply circuit for a relay. Background Art

[0002] A relay is an electrically controlled switch device. When a voltage and current are applied to the iron core coil, an electromagnetic suction force is generated on the iron core to attract the armature switch. When the power supply to the iron core coil is cancelled, the electromagnetic suction force disappears, and the armature switch disconnects under the action of a spring. In this way, the operation of the circuit connected to the relay switch is realized. Among them, the power battery pack of an electric vehicle uses a relay as a switch.

[0003] The output current and voltage of the power battery pack of an electric vehicle are relatively high, which requires the relay to have a large suction force, that is, it is necessary to continuously apply a relatively high voltage and current to the iron core coil of the relay. Generally, an electric vehicle uses a lead-acid battery to supply voltage and current to the relay. The characteristic of a lead-acid battery is that long-term output of a large current will reduce the output voltage, which results in insufficient voltage and current applied to the iron core coil, causing the relay to fail to attract and affecting the output operation of the power battery pack.

[0004] No technical solution capable of solving the problem that the relay fails to attract has been found in the prior art. Summary of the Invention

[0005] In view of this, the present invention provides a power supply circuit for a relay, which can solve the problem that the relay still fails to attract due to unstable power supply of the lead-acid battery.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A power supply circuit for a relay, comprising:

[0008] A switch unit whose first end is connected to the first output end of the power battery pack; the first output end of the power battery pack is connected in parallel with the second output end of the power battery pack;

[0009] A DC / DC controller whose input end is connected to the second end of the switch unit, and the output end of the DC / DC controller is connected to the electrode of a first relay installed at the second output end of the power battery pack for supplying power to the first relay;

[0010] Wherein, the first relay is used to control the opening and closing of the first output end of the power battery pack.

[0011] Optionally, the switch unit is a semiconductor metal oxide MOS transistor or a second relay.

[0012] Optionally, the power supply circuit further comprises:

[0013] A power supply battery with its output terminal connected to the semiconductor metal-oxide-semiconductor (MOS) transistor or the second relay, for supplying power to the semiconductor metal-oxide-semiconductor (MOS) transistor or the second relay.

[0014] Optionally, the power supply battery is a lead-acid battery.

[0015] Optionally, the input terminal of the power supply battery is connected to the output terminal of the DC / DC controller.

[0016] Optionally, the power supply circuit further includes: a current-limiting resistor installed between the input terminal of the power supply battery and the output terminal of the DC / DC controller.

[0017] Optionally, the resistance value of the current-limiting resistor is the output voltage of the DC / DC controller divided by the rated charging current of the power supply battery.

[0018] Optionally, the DC / DC controller is a single-way step-down DC / DC controller.

[0019] As can be seen from the above technical solutions, the present invention discloses a power supply circuit for a relay, which specifically includes: a switch unit with its first end connected to the first output terminal of a power battery pack; a DC / DC controller with its input terminal connected to the second end of the switch unit, and the output terminal of the DC / DC controller is connected to the electrode of a first relay installed at the second output terminal of the power battery pack; by sequentially connecting the power battery pack, the switch unit, the DC / DC controller and the first relay, power is supplied to the first relay. The present invention uses the DC / DC controller to adjust the output current of the power battery pack to replace the lead-acid battery to supply power to the first relay. Since the DC / DC controller has the characteristic of being able to stably and continuously output voltage and current, it can stably and continuously supply power to the first relay, solving the problem that the first relay cannot be attracted due to unstable power supply of the lead-acid battery, and ensuring the normal operation of the first relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0021] Figure 1 It is a schematic structural diagram of a power supply circuit for a relay disclosed in an embodiment of the present invention;

[0022] Figure 2 It is a schematic structural diagram of the relay disclosed in an embodiment of the present invention;

[0023] Figure 3 The structural schematic diagram of another power supply circuit for a relay disclosed in the embodiment of the present invention;

[0024] Figure 4 The structural schematic diagram of another power supply circuit for a relay disclosed in the embodiment of the present invention. Specific embodiments

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] The present invention provides a power supply circuit for a relay, which can solve the problem that the relay cannot be attracted due to unstable power supply of the lead-acid battery.

[0027] As Figure 1 shown, the embodiment of the present invention discloses a power supply circuit 100 for a relay, including:

[0028] A switch unit 101 and a DC / DC controller 102; wherein:

[0029] The first end of the switch unit 101 is connected to the first output end of the power battery pack 103; the first output end of the power battery pack 103 is connected in parallel with the second output end of the power battery pack 103.

[0030] The input end of the DC / DC controller 102 is connected to the second end of the switch unit 101, and the output end of the DC / DC controller 102 is connected to the electrode of the first relay 104 for supplying power to the first relay 104; the first relay 104 is installed at the second output end of the power battery pack 103. The first relay 104 is used to control the opening and closing of the second output end of the power battery pack 103.

[0031] It should be noted that the DC / DC controller 102 is a voltage converter that effectively outputs a fixed voltage after converting the input voltage, and it has the characteristics of being able to stably provide voltage and current, which exactly meets the condition that the first relay 104 needs to continuously receive voltage and current during operation. Therefore, the present invention uses the DC / DC controller 102 to replace the lead-acid battery and supply power to the first relay 104 that controls the opening and closing of the second output end of the power battery pack 103.

[0032] Combined with Figure 1, when the DC / DC controller 102 continuously outputs voltage and current to the first relay 104, the iron-core coil in the first relay 104 generates a magnetic field under the action of the voltage and current, causing the iron core to generate electromagnetic suction, closing and conducting the armature. The second output terminal of the power battery pack 103 outputs voltage and current to the motor controller 105, and then the motor controller 105 delivers it to the motor 106, and the motor 106 rotates to drive the electric vehicle to travel.

[0033] When the switch unit 101 is disconnected and the DC / DC controller 102 stops continuously outputting voltage and current to the first relay 104, the iron-core coil in the first relay loses the action of voltage and current and no longer generates a magnetic field. The electromagnetic suction of the iron core disappears, and the armature returns to its original position under the action of the spring or its own elastic deformation, the circuit is disconnected, and the second output terminal of the power battery pack 103 no longer outputs voltage and current to the motor controller 105. Thus, the output of the second output terminal of the power battery pack 103 can be controlled by powering on and off the first relay 104 through the DC / DC controller 102.

[0034] However, the DC / DC controller 102 itself cannot generate voltage and current. Therefore, it is necessary to connect the input terminal of the DC / DC controller 102 to the first output terminal of the power battery pack, step down the current and voltage output from the first output terminal of the power battery pack 103 and then transmit it to the first relay 104. In order to control the DC / DC controller 102 to power on and off the first relay 104, a switch unit 101 is added between the first output terminal of the power battery pack 103 and the input terminal of the DC / DC controller 102, and the switch unit 101 is used to control the DC / DC controller 102 to power on and off the first relay 104 by opening and closing.

[0035] Optionally, the switch unit 101 is a Metal Oxide Semiconductor (MOS) transistor or a second relay.

[0036] It should be noted that an MOS transistor is an electrical component with a switching function. The MOS transistor can use a bipolar transistor. When the voltage applied between the base and the emitter reaches a preset value, the collector and the emitter are turned on, just like a switch is connected, enabling the power battery pack 103 to output current and voltage to the DC / DC controller 102 through the first output terminal; the MOS transistor can also use a field effect transistor. When the voltage applied between the gate and the source reaches a preset value, the drain and the source are turned on, just like a switch is connected, enabling the power battery pack to output current and voltage to the DC / DC controller 102 through the first output terminal; conversely, when the voltage applied between the base and the emitter, or the voltage applied between the gate and the source is 0 or less than the preset value, the circuit is not conducting, equivalent to the switch being disconnected, thus playing a switching function.

[0037] The second relay is also an electrically controlled switch device. For example, Figure 2 as shown, when a voltage and current are applied to the iron-core coil 22 through the electrode 21, an electromagnetic suction force is generated on the iron core 23 to attract the armature switch 24. Just like when the switch is closed, the power battery pack 103 outputs current and voltage to the DC / DC controller 102 through the first output terminal; when the power supply to the iron-core coil 22 is cancelled, the electromagnetic suction force disappears, and the armature switch 24 disconnects under the action of the spring 25, which is equivalent to the switch being opened, thus playing the switch function.

[0038] Optionally, the power supply circuit further includes:

[0039] a power supply battery with an output terminal connected to the semiconductor metal oxide MOS transistor or the second relay, for supplying power to the semiconductor metal oxide MOS transistor or the second relay.

[0040] It should be noted that since both the MOS transistor and the second relay need to have voltage and current applied to achieve the switch function, in the embodiments of the present invention, a power supply battery is provided for the switch unit 101 to provide voltage and current for the MOS transistor or the second relay to achieve the switch function.

[0041] Optionally, the power supply battery is a lead-acid battery.

[0042] It should be noted that a lead-acid battery is a storage battery in which the electrodes are mainly made of lead and its oxides, and the electrolyte is a sulfuric acid solution. In the discharged state of the lead-acid battery, the main component of the positive electrode is lead dioxide, and the main component of the negative electrode is lead; in the charged state, the main components of both the positive and negative electrodes are lead sulfate. The lead-acid battery has the characteristic of safe sealing. During normal operation, the electrolyte will not leak out from the terminals or the casing of the battery. The special absorbent separator keeps the sulfuric acid solution inside, and there is no free acid solution inside the battery, so the battery can be placed in any position. When the internal pressure of the battery exceeds the normal level, the lead-acid battery will release the excess gas and automatically reseal itself to ensure that there is no excess gas inside the battery. And the lead-acid battery uses a lead-calcium alloy grid with an anti-corrosion structure and can be float-charged for 10 - 15 years. Due to the above reliable characteristics of the lead-acid battery and its ability to provide a stable control voltage and current to the switch unit 101, it is the preferred power supply battery for the power supply circuit of the present invention. Of course, other batteries can also be selected according to specific circumstances.

[0043] Further, it should be noted that when the switch unit 101 is the second relay, the rated power of the second relay used should be much smaller than that of the first relay at the second output end of the power battery pack. Since the second output end of the power battery pack supplies power to the motor to drive the electric vehicle, the output voltage and current are much larger than the voltage and current output by the first output end of the power battery pack to the DC / DC controller 102. This requires that the suction force of the first relay be much larger than that of the second relay used in the switch unit 101. Therefore, the suction force required for the second relay used in the switch unit 101 is smaller, and the voltage and current required to attract the armature switch are also relatively small, which can be completely provided by the capacity of the lead-acid battery. Therefore, a lead-acid battery can be used to supply power to the second relay of the switch unit 101.

[0044] Optionally, as Figure 3 shown, in another embodiment of the present invention, in the power supply circuit 100, the input end of the power supply battery 107 is connected to the output end of the DC / DC controller 102.

[0045] Optionally, as Figure 3 shown, the power supply circuit 100 may further include:

[0046] A current-limiting resistor 108 installed between the input end of the power supply battery 107 and the output end of the DC / DC controller 102.

[0047] Optionally, the resistance value of the current-limiting resistor 108 is the output voltage of the DC / DC controller 102 divided by the rated charging current of the power supply battery 107.

[0048] It should be noted that in the present invention, the DC / DC controller 102 charges the power supply battery 107. In order to avoid occupying too much current and affecting the normal power supply of the DC / DC controller 102 to the first relay 104, a battery with a relatively small charging current, such as a lead-acid battery, is selected as the power supply battery 107 to supply power to the switch unit 101.

[0049] Taking the lead-acid battery as an example, the supply current of the lead-acid battery used in general electric vehicles is not greater than 1.5A, while the output current of the general DC / DC controller 102 is 20A. Obviously, we need a current-limiting resistor 108 to reduce the charging current for charging the power supply battery 107. By looking up the used DC / DC controller 102, its output voltage can be obtained. Similarly, the rated charging current of the power supply battery 107 in use can be obtained. According to the circuit formula, the resistance value of the current-limiting resistor 108 can be obtained as the output voltage of the DC / DC controller 102 divided by the rated charging current of the power supply battery 107.

[0050] Optionally, the DC / DC controller is a unidirectional buck DC / DC controller.

[0051] It should be noted that since the DC / DC controller 102 in the present invention only requires a step-down function and needs to prevent current from flowing back into the power battery pack and causing damage to the power battery pack, the power supply circuit of the present invention adopts a unidirectional step-down DC / DC controller.

[0052] Optionally, as Figure 4 shown, in another embodiment of the present invention, the power supply circuit further includes: the output end of the DC / DC controller 102 is connected to the peripheral device 109 of the electric vehicle, and is used to adjust the output current of the first output end of the power battery pack to supply power to the peripheral device.

[0053] It should be noted that the peripheral devices include headlights, horns, instrument panels, etc. Since the output voltage of the power battery pack is generally 130V, while the voltage of the peripheral devices of the electric vehicle is generally 12V, it is necessary for the DC / DC controller to reduce the power supply voltage to the peripheral devices to ensure the normal operation of each peripheral device of the electric vehicle.

[0054] In the present invention, the output circuit of the DC / DC controller 102 where the current-limiting resistor is connected, the output circuit of the DC / DC controller 102 for supplying power to the peripheral devices of the whole vehicle, and the circuit of the DC / DC controller 102 connected to the first relay are in parallel. And since the charging current of the power supply battery and the power supply current of the peripheral devices are smaller than the voltage and current required by the first relay, it will not affect the power supply work of the DC / DC controller 102 to the first relay.

[0055] Moreover, due to the existence of the switch unit 101, the electric vehicle can charge the power supply battery and supply power to each peripheral device of the electric vehicle in a parked state without closing the first relay, reducing the loss of the first relay.

[0056] It should be further noted that since the output circuit of the DC / DC controller 102 where the current-limiting resistor is connected, the output circuit of the DC / DC controller 102 for supplying power to the peripheral devices of the whole vehicle, and the circuit of the DC / DC controller 102 connected to the first relay are in parallel, and the three parallel circuits do not always need to be connected simultaneously, the present invention can regulate the power flow through the Battery Management System (BMS) to improve the power utilization rate.

[0057] For example, when the user of an electric vehicle controls the vehicle to stop and temporarily leaves to handle some matters, due to the vehicle's operation for a period of time, the power supply battery keeps the switch unit 101 closed, ensuring that the first relay is in the state where the armature switch is closed, resulting in a certain loss of the power supply battery's power. At this time, when the electric vehicle stops, the battery management system can cut off the voltage and current supplied to the first relay and only supply the power supply battery, thereby achieving the charging of the power supply battery even when the electric vehicle stops.

[0058] In the power supply circuit of the relay disclosed in the embodiment of the present invention, it specifically includes: a switch unit with its first end connected to the first output end of the power battery pack; a DC / DC controller with its input end connected to the second end of the switch unit, and the output end of the DC / DC controller is connected to the electrode of the first relay installed at the second output end of the power battery pack; the power battery pack, the switch unit, the DC / DC controller, and the first relay are connected in sequence to supply power to the first relay. The present invention uses the DC / DC controller to adjust the output current of the power battery pack to supply power to the first relay instead of the lead-acid battery. Since the DC / DC controller has the characteristic of being able to stably and continuously output voltage and current, it can stably and continuously supply power to the first relay, solving the problem that the first relay cannot be attracted due to unstable power supply of the lead-acid battery and ensuring the normal operation of the first relay.

[0059] It should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, so that a process, method, commodity or device including a series of elements not only includes those elements but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, commodity or device. Without further limitations, the element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, commodity or device including the element.

[0060] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems or computer program products. Therefore, the present application can take the form of a completely hardware embodiment, a completely software embodiment or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0061] The above are only the embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A power supply circuit for a relay, characterized in that, Comprising: A switch unit with its first end connected to the first output terminal of the power battery pack; The first output terminal of the power battery pack is in parallel with the second output terminal of the power battery pack; A DC / DC controller with its input terminal connected to the second end of the switch unit, and the output terminal of the DC / DC controller is connected to the electrode of a first relay installed at the second output terminal of the power battery pack, for supplying power to the first relay; Wherein, the first relay is used to control the opening and closing of the second output terminal of the power battery pack. When the first relay is closed, the second output terminal of the power battery pack outputs voltage and current to the motor controller.

2. The power supply circuit according to claim 1, wherein The switch unit is a semiconductor metal oxide MOS transistor or a second relay.

3. The power supply circuit according to claim 2, wherein Further comprising: A power supply battery with its output terminal connected to the semiconductor metal oxide MOS transistor or the second relay, for supplying power to the semiconductor metal oxide MOS transistor or the second relay.

4. The power supply circuit according to claim 3, wherein The power supply battery is a lead-acid battery.

5. The power supply circuit according to claim 3, wherein The input terminal of the power supply battery is connected to the output terminal of the DC / DC controller.

6. The power supply circuit according to claim 5, characterized in that, Further comprising: A current-limiting resistor installed between the input terminal of the power supply battery and the output terminal of the DC / DC controller.

7. The power supply circuit according to claim 6, wherein The resistance value of the current-limiting resistor is the output voltage of the DC / DC controller divided by the rated charging current value of the power supply battery.

8. The power supply circuit according to claim 1, characterized in that The DC / DC controller is a unidirectional buck DC / DC controller.

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