Gear control circuit for electric vehicle air heater

Abstract

The application discloses an electric automobile air heater gear control circuit, which comprises a plurality of relays, the contacts of a first relay and a second relay are respectively connected in series in the power supply circuit of a first fan and a second fan, one end of the coil of the first relay is connected with a first voltage input end, and the other end is grounded, one end of the coil of the second relay is connected with a second voltage input end, and the other end is grounded, the contacts of a fourth relay and a fifth relay are respectively connected in series in the power supply circuit of a first heating element and a second heating element, one end of the coil of the fourth relay is connected with the first voltage input end and the second voltage input end, and the other end is grounded, one end of the coil of the fifth relay is connected with the second voltage input end, and the other end is grounded, and the first voltage input end and the second voltage input end are connected with an input voltage through a gear control switch. The application can realize PTC heating through a high-voltage battery at low cost, and hot air is sent out through the fan to warm the driver.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of vehicle air conditioning heating, and particularly relates to an electric vehicle air heater gear control circuit. BACKGROUND

[0002] New energy vehicles have become a major topic in the current automobile market. In new energy buses, it is not possible to use engine waste heat for heating as in fuel vehicles, and therefore, there is an urgent need to design a heating scheme suitable for new energy buses. SUMMARY

[0003] The purpose of the application is to overcome the defects of the prior art and provide an electric vehicle air heater gear control circuit. The application can realize PTC heating by high-voltage battery at low cost, and hot air is sent out by a fan to warm the driver.

[0004] The technical scheme of the application is as follows: The application discloses an electric vehicle air heater gear control circuit, which comprises a first voltage input end, a second voltage input end, a first heating element, a second heating element, a first fan, a second fan and a plurality of relays. The contact points of a first relay K1 are connected in series in the power supply circuit of the first fan, one end of the coil of the first relay K1 is connected with the first voltage input end, and the other end is grounded or connected with the negative pole of the power supply. The contact points of a second relay K2 are connected in series in the power supply circuit of the second fan, one end of the coil of the second relay K2 is connected with the second voltage input end, and the other end is grounded or connected with the negative pole of the power supply. The contact points of a fourth relay K4 are connected in series in the power supply circuit of the first heating element, one end of the coil of the fourth relay K4 is connected with the first voltage input end and the second voltage input end, and the other end is grounded or connected with the negative pole of the power supply. The contact points of a fifth relay K5 are connected in series in the power supply circuit of the second heating element, one end of the coil of the fifth relay K5 is connected with the second voltage input end, and the other end is grounded or connected with the negative pole of the power supply. The first voltage input end and the second voltage input end are connected with the input voltage through a gear control switch.

[0005] Further, the seventh diode D7 and the eighth diode D8 are connected in series between one end of the coil of the fifth relay K5 and the second voltage input end. The anode of the eighth diode D8 is connected with the second voltage input end, the cathode of the eighth diode D8 is connected with the anode of the seventh diode D7, and the cathode of the seventh diode D7 is connected with one end of the coil of the fifth relay K5.

[0006] One end of the coil of the fourth relay K4 is connected in series with the second voltage input end, and a first diode D1 and an eighth diode D8 are connected in series between the other end of the coil of the fourth relay K4 and the second voltage input end; the positive electrode of the eighth diode D8 is connected with the second voltage input end, the negative electrode of the eighth diode D8 is connected with the positive electrode of the first diode D1, the negative electrode of the first diode D1 is connected with one end of the coil of the fourth relay K4, and a second diode D2 and a ninth diode D9 are connected in series between the other end of the coil of the fourth relay K4 and the first voltage input end; the positive electrode of the ninth diode D9 is connected with the first voltage input end, the negative electrode of the ninth diode D9 is connected with the positive electrode of the second diode D2, and the negative electrode of the second diode D2 is connected with one end of the coil of the fourth relay K4.

[0007] Further, a freewheeling diode is connected in parallel across the coil of each relay; the positive electrode of the freewheeling diode is grounded or connected with the negative electrode of the power supply; and a capacitor is connected in parallel across the coil of each relay.

[0008] Further, the electric vehicle air heater gear control circuit further comprises a first TVS tube and a second TVS tube, one end of the first TVS tube is connected with the first voltage input end, the other end of the first TVS tube is grounded or connected with the negative electrode of the power supply, one end of the second TVS tube is connected with the second voltage input end, and the other end of the second TVS tube is grounded or connected with the negative electrode of the power supply.

[0009] Further, the electric vehicle air heater gear control circuit further comprises a temperature controller, the temperature controller is used for collecting the temperature of the heating core comprising the first heating element and the second heating element, the temperature controller is connected in series in the power supply circuit of the fourth relay K4 and the power supply circuit of the fifth relay K5, and when the temperature collected by the temperature controller exceeds a set value, the power supply circuit of the fourth relay K4 and the power supply circuit of the fifth relay K5 are disconnected.

[0010] Further, the electric vehicle air heater gear control circuit further comprises a third relay K3, the coil of the third relay K3 is connected in parallel with the coil of the fourth relay K4, the normally open contact of the third relay K3 is connected in series in the power supply circuit of the indicator lamp; a temperature controller is connected in series in the power supply circuit of the third relay K3, and the temperature controller is used for collecting the temperature of the heating core comprising the first heating element and the second heating element, and when the temperature collected by the temperature controller exceeds a set value, the power supply circuit of the third relay K3 is disconnected.

[0011] Further, one end of the first fan is connected with the first voltage input end through the normally open contact of the first relay K1, the other end of the first fan is grounded or connected with the negative pole of the power supply, forming a power supply circuit of the first fan, the ninth diode D9 is connected in series between the first voltage input end and the normally open contact of the first relay K1, the positive pole of the ninth diode D9 is connected with the first voltage input end, and the negative pole of the ninth diode D9 is connected with the normally open contact of the first relay K1, one end of the second fan is connected with the second voltage input end through the normally open contact of the second relay K2, the other end of the second fan is grounded or connected with the negative pole of the power supply, forming a power supply circuit of the second fan, the eighth diode D8 is connected in series between the second voltage input end and the normally open contact of the second relay K2, the positive pole of the eighth diode D8 is connected with the second voltage input end, and the negative pole of the eighth diode D8 is connected with the normally open contact of the second relay K2.

[0012] Further, the power supply circuit of the first fan is connected in series with a voltage dividing device.

[0013] Further, the first heating element and the second heating element jointly constitute a heating core.

[0014] Further, the gear control switch is a single-pole double-throw switch, the moving end of the single-pole double-throw switch is connected with the input voltage, one fixed end of the single-pole double-throw switch is connected with the first voltage input end, and the other fixed end of the single-pole double-throw switch is connected with the second voltage input end.

[0015] The application has at least the following beneficial effects: the application can realize the switching of the power input through a single-pole double-throw switch, realize the switching of two gears, does not need a controller, and can realize the heating of the PTC through the high-voltage battery at low cost and send out hot air through the fan to warm the driver.

[0016] The circuit of the application also has an over-temperature protection function, and stops working when the temperature of the core exceeds the set temperature, such as 90 DEG C, and resumes working when the temperature is less than or equal to the set temperature, such as 90 DEG C.

[0017] The circuit of the application also has an anti-interference and anti-surge function. DETAILED DESCRIPTION

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0019] Figure 1The circuit diagram of the electric vehicle air heater gear control circuit provided by the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0021] The terms "first", "second" are only used for description purpose, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features; in the description of the present application, unless otherwise specified, the meaning of "multiple", "several" is two or more.

[0022] Referring to Figure 1 The embodiment of the present application provides an electric vehicle air heater gear control circuit, which comprises a first voltage input end (i.e. the first voltage input end of a connector J1 or the positive pole of a power supply, such as the first input end of +24V), a second voltage input end (the second voltage input end of the connector J1 or the positive pole of the power supply, such as the second input end of +24V), a first heating element, a second heating element, a first fan, a second fan and a plurality of relays, wherein the normally open contact of the first relay K1 is connected in series in the power supply circuit of the first fan, one end of the coil of the first relay K1 is connected with the first voltage input end, and the other end is grounded or connected with the negative pole of the power supply (the ground in this embodiment is connected with the ground pin GND of the connector J1), the normally open contact of the second relay K2 is connected in series in the power supply circuit of the second fan, one end of the coil of the second relay K2 is connected with the second voltage input end, and the other end is grounded or connected with the negative pole of the power supply, the normally open contact of the fourth relay K4 is connected in series in the power supply circuit of the first heating element, one end of the coil of the fourth relay K4 is connected with the first voltage input end and the second voltage input end, and the other end is grounded or connected with the negative pole of the power supply, the normally open contact of the fifth relay K5 is connected in series in the power supply circuit of the second heating element, one end of the coil of the fifth relay K5 is connected with the second voltage input end, and the other end is grounded or connected with the negative pole of the power supply, and the first voltage input end and the second voltage input end are connected with an input voltage (i.e. a low-voltage side power supply voltage) through a gear control switch. Two fans are used to blow PTC heating air.

[0023] One end of the first heating element is connected with the negative pole HV- of the high-voltage power supply, the other end of the first heating element is connected with the positive pole HV+ of the high-voltage power supply through the normally open contact of the fourth relay K4, one end of the second heating element is connected with the negative pole HV- of the high-voltage power supply, the other end of the second heating element is connected with the positive pole HV+ of the high-voltage power supply through the normally open contact of the fifth relay K5.

[0024] Further, the seventh diode D7 and the eighth diode D8 are connected in series between one end of the coil of the fifth relay K5 and the second voltage input end; the positive pole of the eighth diode D8 is connected with the second voltage input end, the negative pole of the eighth diode D8 is connected with the positive pole of the seventh diode D7, and the negative pole of the seventh diode D7 is connected with one end of the coil of the fifth relay K5.

[0025] The first diode D1 and the eighth diode D8 are connected in series between one end of the coil of the fourth relay K4 and the second voltage input end; the positive pole of the eighth diode D8 is connected with the second voltage input end, the negative pole of the eighth diode D8 is connected with the positive pole of the first diode D1, and the negative pole of the first diode D1 is connected with one end of the coil of the fourth relay K4, and the second diode D2 and the ninth diode D9 are connected in series between one end of the coil of the fourth relay K4 and the first voltage input end; the positive pole of the ninth diode D9 is connected with the first voltage input end, the negative pole of the ninth diode D9 is connected with the positive pole of the second diode D2, and the negative pole of the second diode D2 is connected with one end of the coil of the fourth relay K4.

[0026] The ninth diode D9, the eighth diode D8, the seventh diode D7, the second diode D2 and the first diode D1 are used to prevent the positive and negative poles of the power supply (such as 24V) from being reversely connected.

[0027] Further, a freewheeling diode is connected in parallel across the coil of each relay; the positive pole of the freewheeling diode is connected to the ground or the negative pole of the power supply; and a capacitor is connected in parallel across the coil of each relay. The freewheeling diode is used to absorb the reverse electromotive force generated when the relay is switched from being attracted to being disconnected. For example, the third diode D3 and the first capacitor C1 are connected in parallel across the coil of the first relay K1. The fourth diode D4 and the second capacitor C2 are connected in parallel across the coil of the second relay K2. The fifth diode D5 and the third capacitor C3 are connected in parallel across the coil of the third relay K3. The fifth diode D5 and the third capacitor C3 are also connected in parallel across the coil of the fourth relay K4. The sixth diode D6 and the fourth capacitor C4 are connected in parallel across the coil of the fifth relay K5.

[0028] Further, the electric vehicle air heater gear control circuit of the present application further comprises a first TVS tube and a second TVS tube, one end of the first TVS tube is connected with the first voltage input end, the other end of the first TVS tube is grounded or connected with the negative electrode of the power supply, one end of the second TVS tube is connected with the second voltage input end, the other end of the second TVS tube is grounded or connected with the negative electrode of the power supply.

[0029] Further, the electric vehicle air heater gear control circuit of the present application further comprises a temperature controller T1, the temperature controller T1 is used to collect the temperature of the heating core containing the first heating element and the second heating element, the temperature controller is connected in series in the power supply circuit of the fourth relay K4 and the power supply circuit of the fifth relay K5, when the temperature collected by the temperature controller exceeds the set value, the power supply circuit of the fourth relay K4 and the power supply circuit of the fifth relay K5 are disconnected.

[0030] The temperature controller is used for core temperature protection.

[0031] Further, the electric vehicle air heater gear control circuit of the present application further comprises a third relay K3, the coil of the third relay K3 is connected in parallel with the coil of the fourth relay K4, the normally open contact of the third relay K3 is connected in series in the power supply circuit of the indicator lamp; a temperature controller is connected in series in the power supply circuit of the third relay K3, the temperature controller is used to collect the temperature of the heating core containing the first heating element and the second heating element, when the temperature collected by the temperature controller exceeds the set value, the power supply circuit of the third relay K3 is disconnected. The two ends of the normally open contact of the third relay K3 are respectively connected with the pins OUT1 and OUT2 of the connector J1, the connector J1 is externally connected with the indicator lamp on the bus. The pins OUT1 and OUT2 of the connector J1 are connected in series in the power supply circuit of the indicator lamp.

[0032] The coil of the first relay K1, the coil of the second relay K2, the coil of the third relay K3, the coil of the fourth relay K4 and the coil of the fifth relay K5 are connected with the ground or the negative electrode of the power supply in the connector J1 in sequence. A ground or negative electrode of the power supply wire is led out from the ground or negative electrode of the power supply pin GND of the connector J1, the temperature controller T1 is connected in series in the ground or negative electrode of the power supply wire, the connection points of the coil of the first relay K1 and the coil of the second relay K2 with the ground or negative electrode of the power supply wire are located between the connector J1 and the temperature controller T1 (i.e. located on the side of the temperature controller T1 close to the connector J1), the connection points of the coil of the third relay K3, the coil of the fourth relay K4 and the coil of the fifth relay K5 with the ground or negative electrode of the power supply wire are located on the side of the temperature controller T1 away from the connector J1.

[0033] Further, one end of the first fan is connected with the first voltage input end through the normally open contact of the first relay K1, the other end of the first fan is grounded or connected with the negative pole of the power supply, forming a power supply circuit of the first fan, the ninth diode D9 is connected in series between the first voltage input end and the normally open contact of the first relay K1, the positive pole of the ninth diode D9 is connected with the first voltage input end, the negative pole of the ninth diode D9 is connected with the normally open contact of the first relay K1, one end of the second fan is connected with the second voltage input end through the normally open contact of the second relay K2, the other end of the second fan is grounded or connected with the negative pole of the power supply, forming a power supply circuit of the second fan, the eighth diode D8 is connected in series between the second voltage input end and the normally open contact of the second relay K2, the positive pole of the eighth diode D8 is connected with the second voltage input end, the negative pole of the eighth diode D8 is connected with the normally open contact of the second relay K2.

[0034] Further, the power supply circuit of the first fan is connected in series with a voltage dividing device.

[0035] Further, the first heating element and the second heating element jointly constitute a heating core.

[0036] Further, the gear control switch is a single-pole double-throw switch, the moving end of the single-pole double-throw switch is connected with the input voltage, one fixed end of the single-pole double-throw switch is connected with the first voltage input end, and the other fixed end of the single-pole double-throw switch is connected with the second voltage input end.

[0037] The circuit of the present application has a low-voltage side power supply voltage of 24V and a high-voltage side power supply voltage of 400-640V, and has two gear controls.

[0038] The low-gear equivalent circuit is as follows: Figure 1As shown: (1) relay K1 is closed, relay K2 is disconnected, the fan and resistor R1 in series to form a voltage divider circuit, the fan works below the low voltage input voltage. (2) contactor K4 is closed, contactor K5 is disconnected, PTC1 works, PTC2 does not work. (3) relay K3 is closed, OUT1, OUT2 is turned on. (4) temperature controller T1 is disconnected after over-temperature, PTC1 does not work, OUT1, OUT2 is open; T1 temperature < 90 degrees after recovery, PTC1 resumes work, OUT1, OUT2 is turned on.

[0039] High-grade equivalent circuit: as Figure 1 As shown: (1) relay K1 is disconnected, relay K2 is closed, the low voltage input voltage is directly added to the fan, the fan works. (2) contactor K4 is closed, contactor K5 is closed, PTC1 works, PTC2 works. (3) relay K3 is closed, OUT1, OUT2 is turned on. (4) temperature controller T1 is disconnected after over-temperature, PTC1, PTC2 does not work, OUT1, OUT2 is open; T1 temperature < 90 degrees after recovery, PTC1, PTC2 resumes work, OUT1, OUT2 is turned on.

[0040] Protection circuit: (1) high-grade and low-grade low-voltage input end is connected to TVS tube: TVS1, TVS2, used for absorbing surge, preventing static electricity, overvoltage protection, preventing ESD. (2) the two ends of the relay and contactor coil are connected to the freewheeling diode: D3, D4, D5, D6, used for absorbing the reverse electromotive force generated when the relay and contactor are attracted to the disconnected. (3) temperature controller T1 is connected in series with the working circuit of the contactor low-voltage coil, once the temperature is too high, the temperature controller is disconnected, the contactor is released, PTC1, PTC2 stops working, preventing over-temperature damage.

[0041] All relays in the present application can be replaced by contactors with equivalent functions.

[0042] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An electric vehicle air heater range control circuit, characterized by: The application relates to a heating device, which comprises a first voltage input end, a second voltage input end, a first heating element, a second heating element, a first fan, a second fan and a plurality of relays, the first heating element and the second heating element jointly form a heating core, wherein the contacts of the first relay are connected in series in a power supply circuit of the first fan, one end of the coil of the first relay is connected with the first voltage input end, the other end is grounded or connected with a negative electrode of a power supply, the contacts of the second relay are connected in series in a power supply circuit of the second fan, one end of the coil of the second relay is connected with the second voltage input end, the other end is grounded or connected with the negative electrode of the power supply, the contacts of the fourth relay are connected in series in a power supply circuit of the first heating element, one end of the coil of the fourth relay is connected with the first voltage input end and the second voltage input end, the other end is grounded or connected with the negative electrode of the power supply, the contacts of the fifth relay are connected in series in a power supply circuit of the second heating element, one end of the coil of the fifth relay is connected with the second voltage input end, the other end is grounded or connected with the negative electrode of the power supply, the first voltage input end and the second voltage input end are connected with an input voltage through a gear control switch, and the gear control switch is used for realizing switching of the input power supply. The seventh diode and the eighth diode are connected in series between one end of the coil of the fifth relay and the second voltage input end, the first diode and the eighth diode are connected in series between one end of the coil of the fourth relay and the second voltage input end, the second diode and the ninth diode are connected in series between one end of the coil of the fourth relay and the first voltage input end, the negative electrode of the first diode is connected with one end of the coil of the fourth relay, and the negative electrode of the second diode is connected with one end of the coil of the fourth relay.

2. The electric vehicle air heater range control circuit of claim 1, wherein: The positive electrode of the eighth diode is connected with the second voltage input end, the negative electrode of the eighth diode is connected with the positive electrode of the seventh diode, and the negative electrode of the seventh diode is connected with one end of the coil of the fifth relay. The positive electrode of the eighth diode is connected with the second voltage input end, the negative electrode of the eighth diode is connected with the positive electrode of the first diode, the positive electrode of the ninth diode is connected with the first voltage input end, and the negative electrode of the ninth diode is connected with the positive electrode of the second diode.

3. The electric vehicle air heater range control circuit of claim 1, wherein: The two ends of the coil of each relay are connected in parallel with a freewheeling diode, the positive electrode of the freewheeling diode is grounded or connected with the negative electrode of the power supply, and the two ends of the coil of each relay are connected in parallel with a capacitor.

4. The electric vehicle air heater range control circuit of claim 1, wherein: The application further comprises a first TVS tube and a second TVS tube, one end of the first TVS tube is connected with the first voltage input end, the other end of the first TVS tube is grounded or connected with the negative electrode of the power supply, one end of the second TVS tube is connected with the second voltage input end, and the other end of the second TVS tube is grounded or connected with the negative electrode of the power supply.

5. The electric vehicle air heater range control circuit of claim 1, wherein: The application further comprises a temperature controller, the temperature controller is used for collecting the temperature of the heating core comprising the first heating element and the second heating element, the temperature controller is connected in series in a power supply circuit of the fourth relay and a power supply circuit of the fifth relay, and when the temperature collected by the temperature controller exceeds a set value, the power supply circuit of the fourth relay and the power supply circuit of the fifth relay are disconnected.

6. The electric vehicle air heater range control circuit of claim 1 or 5, wherein: The third relay has a coil connected in parallel with the coil of the fourth relay, and the normally open contact of the third relay is connected in series in the power supply circuit of the indicator light; a temperature controller is connected in series in the power supply circuit of the third relay, and the temperature controller is used to collect the temperature of the heating core containing the first heating element and the second heating element, and when the temperature collected by the temperature controller exceeds the set value, the power supply circuit of the third relay is disconnected.

7. The electric vehicle air heater range control circuit of claim 1, wherein: One end of the first fan is connected with the first voltage input end through the normally open contact of the first relay, the other end of the first fan is grounded or connected with the negative pole of the power supply, forming a power supply circuit of the first fan, the ninth diode is connected in series between the first voltage input end and the normally open contact of the first relay, the positive pole of the ninth diode is connected with the first voltage input end, and the negative pole of the ninth diode is connected with the normally open contact of the first relay, one end of the second fan is connected with the second voltage input end through the normally open contact of the second relay, the other end of the second fan is grounded or connected with the negative pole of the power supply, forming a power supply circuit of the second fan, the eighth diode is connected in series between the second voltage input end and the normally open contact of the second relay, the positive pole of the eighth diode is connected with the second voltage input end, and the negative pole of the eighth diode is connected with the normally open contact of the second relay.

8. The electric vehicle air heater range control circuit of claim 1 or 7, wherein: The power supply circuit of the first fan has a voltage dividing device connected in series.

9. The electric vehicle air heater range control circuit of claim 1, wherein: The gear control switch is a single-pole double-throw switch, one movable end of the single-pole double-throw switch is connected with the input voltage, one immovable end of the single-pole double-throw switch is connected with the first voltage input end, and the other immovable end of the single-pole double-throw switch is connected with the second voltage input end.

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