Control circuit for combined air and water heating

Abstract

A control circuit of air heating and water heating two-in-one, comprising: a driving circuit and a heater circuit, the heater circuit comprising: an APTC, a WPTC, an IGBT1 and an IGBT2, the positive pole of a high-voltage power supply is connected with one end of the APTC and one end of the WPTC, the other end of the APTC is connected with the C end of the IGBT1, the other end of the WPTC is connected with the C end of the IGBT2, the E end of the IGBT1 and the E end of the IGBT2 are connected with the negative pole of the high-voltage power supply, the output end of the IGBT drive 1 of the driving circuit is connected with the G end of the IGBT1, and the output end of the IGBT drive 2 of the driving circuit is connected with the G end of the IGBT2. The above-mentioned driving circuit can control the air heating and water heating functions at the same time, reduces the overall cost of the circuit, reduces the space occupied by the circuit, and simplifies the maintenance process.

Description

Technical Field

[0001] This utility model relates to control circuits, and more particularly to a control circuit that combines air heating and water heating. Background Technology

[0002] As the market share of new energy vehicles gradually increases, the demand for PTC heaters is also gradually increasing. Currently, there are two types of PTC heaters in new energy vehicles: one is the air-heated PTC heater (APTC), which is directly installed in the air duct and uses PTC elements to heat the air to provide heating for the cabin; the other is the water-heated PTC heater (WPTC), which is a PTC heating device that uses coolant as the heat transfer medium and is mainly used for low-temperature heating of battery packs, overcharge preheating, and cabin heating.

[0003] The two types of PTC heaters mentioned above are usually found in new energy vehicles. However, existing new energy vehicles typically use two drive circuits to independently control the two types of PTC heaters, resulting in high costs, large space requirements, and complex maintenance. Utility Model Content

[0004] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this utility model is to design a control circuit that combines air heating and water heating. The same control circuit can control both air-heated PTC heaters and water-heated PTC heaters, thereby solving the problems of high cost, large space occupation, and complex maintenance.

[0005] To achieve the above objectives, this utility model provides a control circuit combining air heating and water heating, comprising: a drive circuit and a heater circuit. The drive circuit includes: a low-voltage side circuit, a high-voltage side circuit, an isolation transformer, an isolation optocoupler, and an isolation communication chip. The low-voltage side circuit includes: a low-voltage side MCU and a LIN chip. A low-voltage power supply is connected to the power supply pin of the low-voltage side MCU, and a LIN bus is connected to the LIN chip. The high-voltage side circuit includes: a high-voltage side MCU, IGBT driver 1, and IGBT driver 2. The high-voltage side MCU is simultaneously connected to the input terminals of both IGBT driver 1 and IGBT driver 2. The low-voltage power supply is connected to the input terminal of the isolation transformer, and the positive terminal of the isolation transformer's output terminal is simultaneously connected to the power supply pin of both the high-voltage side MCU and the IGBT driver 1. The power supply pins of the IGBT driver 2 are connected to the power supply pins of the IGBT driver 2. The negative terminal of the output of the isolation transformer is grounded. The low-voltage side MCU and the high-voltage side MCU are interconnected through an isolation optocoupler. The LIN chip and the high-voltage side MCU are interconnected through an isolation communication chip. The heater circuit includes: APTC, WPTC, IGBT1, and IGBT2. The positive terminal of a high-voltage power supply is connected to one end of APTC and one end of WPTC. The other end of APTC is connected to the C terminal of IGBT1. The other end of WPTC is connected to the C terminal of IGBT2. The E terminals of IGBT1 and IGBT2 are both connected to the negative terminal of the high-voltage power supply. The output terminal of IGBT driver 1 is connected to the G terminal of IGBT1. The output terminal of IGBT driver 2 is connected to the G terminal of IGBT2. The aforementioned control circuit integrates APTC and WPTC, realizing the dual functions of air heating and water heating. Since the control circuit can be arranged on a single PCB or control box, space is saved. Since it avoids using two sets of repetitive components, the overall cost is reduced. Since the control logic of APTC and WPTC can be set using a unified software architecture, the maintenance process is simplified. The isolation transformer, isolation optocoupler and isolation communication chip isolate the low-voltage side and high-voltage side of the drive circuit.

[0006] Furthermore, the low-voltage side circuit also includes a MOS, LDO1, LDO2, and a power supply chip. The low-voltage power supply is connected to the input terminals of both LDO1 and LDO2. A MOS is located between the input terminal of LDO2 and the positive terminal of the low-voltage power supply. The output terminal of LDO2 is connected to the input terminal of the power supply chip, and the output terminal of LDO1 is connected to the power supply pin of the low-voltage side MCU. The output terminal of the power supply chip is connected to the input terminal of the isolation transformer. The inclusion of LDO1 and LDO2 effectively stabilizes the power from the low-voltage power supply and transmits the stabilized power to the low-voltage side MCU and power supply chip.

[0007] Furthermore, the high-voltage side circuit also includes an LDO3, with the positive terminal of the isolation transformer's output connected to the input terminal of the LDO3, and the output terminal of the LDO3 connected to the high-voltage side MCU. The inclusion of the LDO3 allows for voltage stabilization of the power supplied to the isolation transformer, and the stabilized power is then transmitted to the high-voltage side MCU.

[0008] Furthermore, the heater circuit also includes a voltage divider resistor 1 and a sampling resistor. The positive terminal of the high-voltage power supply is connected to one end of the voltage divider resistor 1, the other end of the voltage divider resistor 1 is connected to one end of the sampling resistor, the other end of the sampling resistor is connected to the negative terminal of the high-voltage power supply, and one end of the sampling resistor is connected to the high-voltage side MCU. Because of the sampling resistor, the voltage value in the heater circuit can be sampled, and the high-voltage side MCU can be used to determine whether the voltage value is normal.

[0009] Furthermore, the heater circuit also includes: shunt 1, shunt 2, operational amplifier 1, and operational amplifier 2. The emitter (E) terminal of IGBT 1 is connected to the input terminal of shunt 1, and the emitter (E) terminal of IGBT 2 is connected to the input terminal of shunt 2. The output terminals of both shunt 1 and shunt 2 are connected to the negative terminal of the high-voltage power supply. The input terminal of shunt 1 is connected to the high-voltage side MCU via operational amplifier 1, and the input terminal of shunt 2 is connected to the high-voltage side MCU via operational amplifier 2. Because of the inclusion of shunt 1, shunt 2, operational amplifier 1, and operational amplifier 2, the current value in the heater circuit can be sampled, and the high-voltage side MCU can be used to determine whether the current value is normal. In addition, the inclusion of shunt 1 and shunt 2 enables sampling of large currents.

[0010] Furthermore, each APTC, WPTC, IGBT1, and IGBT2 is configured in pairs. The other end of each APTC is connected to the collector (C) terminal of each of the two IGBT1 units. The emitter (E) terminals of each of the two IGBT1 units are connected to the input terminal of shunt 1. The output terminal of IGBT driver 1 is simultaneously connected to the gate (G) terminals of both IGBT1 units. The other end of each WPTC is connected to the collector (C) terminal of each of the two IGBT2 units. The emitter (E) terminals of each of the two IGBT2 units are connected to the input terminal of shunt 2. The output terminal of IGBT driver 2 is simultaneously connected to the gate (G) terminals of both IGBT2 units. The use of multiple APTCs and multiple WPTCs allows for simultaneous heating of multiple locations within the vehicle.

[0011] Furthermore, the control circuit also includes a temperature acquisition circuit, which is connected to the low-voltage side MCU. Because of the included temperature acquisition circuit, the temperature values ​​within the vehicle can be collected.

[0012] Furthermore, the temperature acquisition circuit includes a voltage divider resistor 2 and an NTC. A temperature acquisition power supply is connected to one end of the voltage divider resistor 2, the other end of the voltage divider resistor 2 is connected to one end of the NTC, the other end of the NTC is grounded, and one end of the NTC is connected to the low-voltage side MCU. The temperature acquisition circuit uses the resistance value of the NTC to provide temperature feedback. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the driving circuit involved in this utility model; Figure 2 This is a schematic diagram of the heater circuit involved in this utility model; Figure 3 This is a schematic diagram of the temperature acquisition circuit involved in this utility model. Detailed Implementation

[0014] The technical solution of this utility model will be further described below through embodiments: This invention provides a control circuit combining air heating and water heating, comprising: a drive circuit, a heater circuit, and a temperature acquisition circuit. The temperature acquisition circuit is connected to the drive circuit, and the drive circuit is connected to the heater circuit. When the control circuit is operating, the temperature acquisition circuit transmits temperature information to the drive circuit, and the drive circuit controls the heater circuit to perform heating based on the temperature information.

[0015] Specifically, such as Figure 1As shown, the driving circuit includes: a low-voltage side circuit, a high-voltage side circuit, an isolation transformer, an isolation optocoupler, and an isolation communication chip; the low-voltage side circuit includes: a low-voltage side MCU, a MOS, LDO1, LDO2, a power supply chip, and a LIN chip. The positive and negative terminals LV+ and LV- of the low-voltage power supply are connected to the input terminals of LDO1 and LDO2 simultaneously. A MOS is installed between the input terminal of LDO2 and the positive terminal LV+ of the low-voltage power supply. The output terminal of LDO2 is connected to the input terminal of the power supply chip. The output terminal of LDO1 is connected to the power supply pin of the low-voltage side MCU. The temperature acquisition circuit is connected to the low-voltage side MCU, and the LIN bus is connected to the LIN chip; the high-voltage side circuit includes: a high-voltage side MCU, LDO3, and an IGBT. The outputs of Driver 1, IGBT Driver 2, and LDO3 are connected to the power supply pins of the high-voltage side MCU. The high-voltage side MCU is also connected to the inputs of both IGBT Driver 1 and IGBT Driver 2. The outputs of both IGBT Driver 1 and IGBT Driver 2 are connected to the heater circuit. The output of the power supply chip is connected to the input of the isolation transformer. The positive terminal of the isolation transformer's output is connected to the input of LDO3, the power supply pins of IGBT Driver 1 and IGBT Driver 2, and the negative terminal of the isolation transformer's output is grounded. The low-voltage side MCU and the high-voltage side MCU are interconnected via an isolation optocoupler. The LIN chip and the high-voltage side MCU are interconnected via an isolation communication chip.When the drive circuit is working, the low-voltage power supply outputs low-voltage electricity to LDO1 and LDO2. The MOS acts as an electronic switch. LDO1 reduces the voltage to 5V and outputs it to the low-voltage side MCU, while LDO2 reduces the voltage to 5V and outputs it to the power supply chip. The power supply chip outputs 15V through an isolation transformer and outputs it to IGBT driver 1 and IGBT driver 2. LDO3 reduces the voltage to 5V and outputs it to the high-voltage side MCU, thus supplying power to the low-voltage side MCU, high-voltage side MCU, IGBT driver 1, and IGBT driver 2. The power supply chip controls power transmission, and LDO1, LDO2, and LDO3 are voltage regulators whose operating principle is the same as in existing technologies and will not be described further here. The low-voltage side MCU outputs a feedback signal based on the signal input from the temperature acquisition circuit and inputs the feedback signal to the high-voltage side MCU through an isolation optocoupler. The high-voltage side MCU then supplies power to IGBT driver 1 and IGBT driver 2. T-Driver 2 outputs control signals, and IGBT Driver 1 and IGBT Driver 2 respectively output drive signals to the heater circuit, thereby driving the heater circuit to work. The isolation optocoupler is used to isolate interference between the low-voltage side circuit and the high-voltage side circuit, and its working principle is the same as in existing technologies. The low-voltage side MCU and high-voltage side MCU act as microprocessors, and IGBT Driver 1 and IGBT Driver 2 act as IGBT drivers; their working principles are also the same as in existing microprocessors and IGBT drivers, and will not be described further here. The LIN bus outputs bus signals to the LIN chip, and the LIN chip outputs feedback signals to the high-voltage side MCU through the isolation communication chip. The LIN chip processes the LIN bus signals, and the isolation communication chip achieves signal coupling and transmission in an electrically isolated state. The working principles of the LIN chip and the isolation communication chip are the same as in existing technologies, and will not be described further here.

[0016] In this embodiment, the low-voltage side MCU uses the KF8A100CSD microprocessor from Shanghai Chipwin Microelectronics Technology Co., Ltd.; the high-voltage side MCU uses the GD32A503CCT30E microprocessor from GigaDevice Semiconductor Co., Ltd. Of course, in other embodiments, the low-voltage side MCU and the high-voltage side MCU can also use other models of microprocessors.

[0017] Specifically, such as Figure 2As shown, the heater circuit includes: APTC, WPTC, IGBT1, IGBT2, voltage divider resistor 1, sampling resistor, shunt 1, shunt 2, operational amplifier 1, and operational amplifier 2. The positive terminal HV+ of the high-voltage power supply is connected to one end of voltage divider resistor 1, one end of APTC, and one end of WPTC. The other end of voltage divider resistor 1 is connected to one end of the sampling resistor. The other end of APTC is connected to the collector (C) terminal of IGBT1. The emitter (E) terminal of IGBT1 is connected to the input terminal of shunt 1. The other end of WPTC is connected to the input terminal of IGBT2. The C terminal is connected, the E terminal of IGBT2 is connected to the input terminal of shunt 2, the other end of the sampling resistor, the output terminal of shunt 1 and the output terminal of shunt 2 are all connected to the negative terminal HV- of the high voltage power supply, the output terminal of IGBT driver 1 is connected to the G terminal of IGBT1, the output terminal of IGBT driver 2 is connected to the G terminal of IGBT2, one end of the sampling resistor is connected to the high voltage side MCU, the input terminal of shunt 1 is connected to the high voltage side MCU through operational amplifier 1, and the input terminal of shunt 2 is connected to the high voltage side MCU through operational amplifier 2. When the heater circuit is working, the high-voltage power supply outputs high-voltage electricity to APTC and WPTC; IGBT driver 1 and IGBT driver 2 drive the switching on and off of IGBT1 and IGBT2 respectively, thereby controlling the operation of APTC and WPTC respectively; Shunt 1 and shunt 2 are used to reduce the output voltage of IGBT1 and IGBT2 respectively, and output to the high-voltage side MCU through operational amplifier 1 and operational amplifier 2 respectively, thereby determining whether the current value of the heater circuit is normal. Among them, operational amplifier 1 and operational amplifier 2 are both operational amplifiers used to compare the difference between the current value of the heater circuit and the set current value; voltage divider resistor 1 is used to reduce the voltage at the input terminal of the sampling resistor, and the high-voltage side MCU determines whether the voltage value of the heater circuit is normal.

[0018] In this embodiment, there are two APTCs, two WPTCs, two IGBT1s, and two IGBT2s. The outputs of the two APTCs are connected to the collector (C) terminals of the two IGBT1s, and the emitter (E) terminals of the two IGBT1s are connected to the input terminals of shunt 1. IGBT driver 1 is connected to the gate (G) terminals of both IGBT1s. The outputs of the two WPTCs are connected to the collector (C) terminals of the two IGBT2s, and the emitter (E) terminals of the two IGBT2s are connected to the input terminals of shunt 2. IGBT driver 2 is also connected to the gate (G) terminals of both IGBT2s. In other words, there are two air-heating drive circuits formed by the series connection of APTCs and IGBT1s, which are connected in parallel and both are connected in series with shunt 1. Similarly, there are two water-heating drive circuits formed by the series connection of WPTCs and IGBT2s, which are connected in parallel and both are connected in series with shunt 2. Of course, in other embodiments, there can be three or more APTCs, WPTCs, IGBT1s, and IGBT2s.

[0019] Specifically, such as Figure 3As shown, the temperature acquisition circuit includes: a voltage divider resistor 2 and an NTC. The temperature acquisition power supply is connected to one end of the voltage divider resistor 2, and the other end of the voltage divider resistor 2 is connected to one end of the NTC. The other end of the NTC is grounded, and one end of the NTC is connected to the low-voltage side MCU. When the temperature acquisition circuit is working, the temperature acquisition power supply supplies power to the voltage divider resistor 2. The temperature acquisition power supply is a 5V power supply. The voltage divider resistor 2 is used to reduce the voltage at the input terminal of the NTC. The NTC, or thermistor, reflects the ambient temperature value through its input terminal. It is connected to the low-voltage side MCU through its input terminal to achieve temperature information acquisition.

[0020] The above-mentioned combined air heating and water heating control circuit has the following advantages: 1. Reduced vehicle space and weight: Traditional APTC and WPTC control boards are designed independently, requiring separate PCBs, connectors, wiring harnesses, and heat dissipation structures, which occupy a lot of space in the vehicle, such as the battery pack, motor compartment, or passenger compartment. However, the control circuit of this utility model can be arranged using the same PCB or a compact control box, which significantly reduces the number of electronic components, such as capacitors, resistors, chips, and connectors, and also shortens the wiring harness length. The overall volume can be reduced by 30% to 50%, and the weight by about 20% to 30%, which is beneficial to the improvement of the range of new energy vehicles (i.e., reducing redundant mass) and the layout of the vehicle's interior space, freeing up space for the battery or passengers.

[0021] 2. Reduced costs and increased production efficiency: By reducing repetitive components such as power chips, MCUs, and sampling resistors, and by decreasing the use of auxiliary materials such as wire harnesses, material costs are saved. Furthermore, assembly processes such as welding, testing, and debugging can be simplified from two sets to one, shortening production line hours, increasing the utilization rate of labor and equipment, and reducing manufacturing costs by approximately 20% to 35%.

[0022] 3. Optimize control coordination to improve thermal management efficiency: Dynamically adjust the power distribution between APTC and WPTC based on real-time needs, such as cabin temperature and battery temperature, to avoid energy waste caused by both operating at full load simultaneously. For example, during low-temperature startup, WPTC is used first to heat the battery for higher efficiency, and APTC is switched to provide heating only after the battery temperature reaches the target level.

[0023] 4. Simplified Software Maintenance and Upgrades: A unified software architecture can be used to configure the control logic of APTC and WPTC, such as PID regulation and fault diagnosis, making maintenance more convenient. Furthermore, function upgrades only require updating one set of software, eliminating the need to debug two separate control boards, significantly reducing the complexity and time cost of OTA upgrades. In addition, underlying drivers, such as PWM output and ADC sampling, can be shared, thereby reducing code redundancy.

Claims

1. A control circuit combining air heating and water heating, comprising: The driving circuit and heater circuit are characterized by: The driving circuit includes: a low-voltage side circuit, a high-voltage side circuit, an isolation transformer, an isolation optocoupler, and an isolation communication chip. The low-voltage side circuit includes: a low-voltage side MCU and a LIN chip. A low-voltage power supply is connected to the power supply pin of the low-voltage side MCU, and a LIN bus is connected to the LIN chip. The high-voltage side circuit includes: a high-voltage side MCU, IGBT driver 1, and IGBT driver 2. The high-voltage side MCU is connected to the input terminals of both IGBT driver 1 and IGBT driver 2. The low-voltage power supply is connected to the input terminal of the isolation transformer. The positive terminal of the output terminal of the isolation transformer is connected to the power supply pins of the high-voltage side MCU, IGBT driver 1, and IGBT driver 2. The negative terminal of the output terminal of the isolation transformer is grounded. The low-voltage side MCU and the high-voltage side MCU are interconnected via an isolation optocoupler. The LIN chip and the high-voltage side MCU are interconnected via an isolation communication chip. The heater circuit includes: APTC, WPTC, IGBT1, and IGBT2. The positive terminal of a high-voltage power supply is connected to one end of both APTC and WPTC. The other end of APTC is connected to the C terminal of IGBT1, and the other end of WPTC is connected to the C terminal of IGBT2. The E terminals of both IGBT1 and IGBT2 are connected to the negative terminal of the high-voltage power supply. The output terminal of IGBT driver 1 is connected to the G terminal of IGBT1, and the output terminal of IGBT driver 2 is connected to the G terminal of IGBT2.

2. The control circuit combining air heating and water heating according to claim 1, characterized in that: The low-voltage side circuit also includes: MOS, LDO1, LDO2 and power supply chip. The low-voltage power supply is connected to the input terminals of both LDO1 and LDO2. A MOS is provided between the input terminal of LDO2 and the positive terminal of the low-voltage power supply. The output terminal of LDO2 is connected to the input terminal of the power supply chip. The output terminal of LDO1 is connected to the power supply pin of the low-voltage side MCU. The output terminal of the power supply chip is connected to the input terminal of the isolation transformer.

3. The control circuit combining air heating and water heating according to claim 1, characterized in that: The high-voltage side circuit also includes an LDO3, the positive terminal of the output of the isolation transformer is connected to the input terminal of the LDO3, and the output terminal of the LDO3 is connected to the high-voltage side MCU.

4. The control circuit combining air heating and water heating according to claim 1, characterized in that: The heater circuit further includes a voltage divider resistor 1 and a sampling resistor. The positive terminal of the high-voltage power supply is connected to one end of the voltage divider resistor 1, the other end of the voltage divider resistor 1 is connected to one end of the sampling resistor, the other end of the sampling resistor is connected to the negative terminal of the high-voltage power supply, and one end of the sampling resistor is connected to the high-voltage side MCU.

5. The control circuit combining air heating and water heating according to claim 1, characterized in that: The heater circuit further includes: shunt 1, shunt 2, operational amplifier 1, and operational amplifier 2. The output terminal of IGBT 1 is connected to the input terminal of shunt 1, and the output terminal of IGBT 2 is connected to the input terminal of shunt 2. The output terminals of shunt 1 and shunt 2 are both connected to the negative terminal of the high-voltage power supply. The input terminal of shunt 1 is connected to the high-voltage side MCU through operational amplifier 1, and the input terminal of shunt 2 is connected to the high-voltage side MCU through operational amplifier 2.

6. The control circuit combining air heating and water heating according to claim 5, characterized in that: Each IGBT has two APTCs, two WPTCs, two IGBT1s, and two IGBT2s. The other end of each APTC is connected to the C terminal of each IGBT1. The E terminal of each IGBT1 is connected to the input terminal of shunt 1. The output terminal of IGBT driver 1 is connected to the G terminal of each IGBT1. The other end of each WPTC is connected to the C terminal of each IGBT2. The E terminal of each IGBT2 is connected to the input terminal of shunt 2. The output terminal of IGBT driver 2 is connected to the G terminal of each IGBT2.

7. The control circuit combining air heating and water heating according to claim 1, characterized in that: The control circuit also includes a temperature acquisition circuit, which is connected to the low-voltage side MCU.

8. The control circuit combining air heating and water heating according to claim 7, characterized in that: The temperature acquisition circuit includes: a voltage divider resistor 2 and an NTC. A temperature acquisition power supply is connected to one end of the voltage divider resistor 2, the other end of the voltage divider resistor 2 is connected to one end of the NTC, the other end of the NTC is grounded, and one end of the NTC is connected to the low-voltage side MCU.

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