PTC heater driving module for high-voltage-resistant new energy automobile air conditioner

Abstract

The invention relates to the technical field of new energy automobile air conditioners, in particular to a PTC heater driving module for a high-voltage-resistant new energy automobile air conditioner, which comprises a PTC heater driving module and a PTC heater, the PTC heater driving module comprises a CPU module, a driving signal module and a sampling circuit module, the driving signal module and the sampling circuit module are connected with the CPU module, and the PTC heater driving module is connected with the CPU module. The CPU module is electrically connected with the PTC heater, and the PTC heater driving module is composed of a high-voltage power supply module and a low-voltage power supply module. According to the PTC heater driving module for the high-voltage-resistant new energy automobile air conditioner, an upper arm chopping power tube and a lower arm fly-wheel diode are arranged, an L-shaped filter circuit is formed by combining an inductor assembly and a capacitor assembly, a PTC heater is isolated from high-voltage power supply, and the high-voltage power supply is processed into continuous adjustable direct current through controllable chopping and LC filtering to drive the PTC heater; and circuit safety is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy automobile air conditioners, and in particular to a high-voltage resistant PTC heater drive module for new energy automobile air conditioners. Background Art

[0002] The PTC heater driver module is a DC heater control switch designed specifically for new energy vehicles. It is mainly used to control ceramic heaters, that is, positive temperature coefficients. Its core is to use semiconductor ceramic materials such as barium titanate, strontium, lead and other metal elements, by adding trace elements such as Sb, Mn, Fe, and additives such as silicon oxide and aluminum oxide, and then firing them at high temperatures. This design enables the PTC electric heater to have efficient heat conversion capabilities and can provide a stable source of heat for the air-conditioning system of electric vehicles. The working principle of the PTC electric heater controller is based on temperature sensitivity. When the temperature sensor in the car detects that the temperature is too high or too low, it will send a signal to the control system. The control system starts the PTC switch based on this signal, so that the compressor of the air-conditioning system starts working to provide cooling or heating in the car to adjust the temperature in the car. This temperature control is not only applicable to air-conditioning systems, but also to heating systems to ensure the comfort of the interior environment.

[0003] At present, new energy vehicles are developing rapidly. In order to improve the endurance, the power density of the battery pack must be increased, and the battery pack voltage must be gradually increased from 300V to 1000V. This background trend towards high voltage has brought new problems to the PTC heaters of the thermal management and air-conditioning systems of new energy vehicles. Due to the increase in voltage, the amplitude of the instantaneous surge current when the PTC heater is turned on and off is exponentially aggravated. At the same time, the current PTC heater power supply structure is directly connected to the high voltage of the battery pack, so the PTC heater also bears the high voltage of the power supply and the voltage spike superimposed on the high voltage line. The amplitude of this superimposed voltage spike generally reaches 2 times the amplitude of the high voltage power supply. The high-voltage power supply environment is accompanied by large current and voltage spikes. For the relay-controlled system, in addition to the problem that the PTC heater itself bears high voltage, it is also easy for the relay contacts to arc and stick, resulting in system failure. For the power tube-controlled system, in addition to the problem that the PTC heater itself bears high voltage, it is also easy for the power tube to break down and burst, resulting in system failure. Therefore, with the gradual increase in voltage, PTC heater drive modules have begun to be broken down and damaged. Failures such as, and reliability has been greatly reduced. Summary of the invention

[0004] The purpose of the present invention is to provide a high-voltage resistant PTC heater driving module for new energy automobile air conditioners to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a high-voltage resistant new energy automobile air conditioner PTC heater drive module, comprising a PTC heater drive module and a PTC heater, the PTC heater drive module comprising an output voltage control module, a CPU module, a drive signal module and a sampling circuit module, the drive signal module and the sampling circuit module are connected to the CPU module, the output voltage control module is electrically connected to the PTC heater, the PTC heater drive module is composed of an output voltage control module, a CPU control module, a drive signal module and a sampling circuit module, the output voltage control module is composed of N1, D9, L6, C36; the CPU control module is composed of a single-chip microcomputer and its peripheral power supply and auxiliary circuit; the drive module is composed of a bridge arm drive circuit and an isolated power supply; the sampling circuit module is composed of an input voltage sampling circuit, an output voltage sampling circuit, a current sampling circuit, and several temperature sampling circuits;

[0006] The PTC heater driving module also includes: an upper arm chopper power tube, a lower arm freewheeling diode, an inductor component and a capacitor component. The upper arm chopper power tube, the inductor component and the PTC heater are connected in series with each other, and the lower arm freewheeling diode and the capacitor component are connected in parallel to the series circuit of the upper arm chopper power tube, the inductor component and the PTC heater.

[0007] In a further embodiment, the sampling circuit module is provided with three groups of acquisition terminals, and the sampling circuits are respectively provided at the input circuit terminal of the upper arm chopper power tube, the output circuit terminal of the inductor component and the negative electrode of the high voltage power supply.

[0008] In a further embodiment, the drive signal module is connected in series with the upper arm chopper power tube, the drive signal module is a module for outputting signals from the CPU module, and the sampling circuit module is a module for inputting signals from the CPU module.

[0009] In a further embodiment, the CPU module is connected to a control power module, the control power module is connected to a low-voltage power supply module, the low-voltage power supply positive electrode and the low-voltage power supply negative electrode are connected in series with the control power module, and the control power module controls the power of the CPU module, the drive signal module, and the sampling circuit module.

[0010] In a further embodiment, the control power module is connected to an isolation power module, and the isolation power module supplies power to the drive signal module.

[0011] In a further embodiment, the CPU module is connected to a communication module, the communication module is provided with a connection interface, and the communication module communicates with an external device via a wired connection.

[0012] In a further embodiment, the PTC heater driving module is provided with a housing, the PTC heater is arranged outside the housing, and the PTC heater is connected to the PTC heater driving module via a wire.

[0013] In a further embodiment, the inductor component and the capacitor component are arranged between the upper arm chopper power tube and the lower arm freewheeling diode to form an "L" type filtering circuit.

[0014] In a further embodiment, the upper arm chopper power tube is one of an IGBT tube, a silicon carbide tube and a MOS tube, and preferably a silicon carbide tube.

[0015] In a further embodiment, the lower arm freewheeling diode is a fast diode, and the position of the lower arm freewheeling diode can be replaced by a lower arm freewheeling power tube. The lower arm freewheeling power tube is one of an IGBT tube, a silicon carbide tube and a MOS tube, and the silicon carbide tube is preferably used here.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention forms an output voltage control module by arranging an upper arm chopper power tube, a lower arm freewheeling diode, an inductor component, and an "L" type filter circuit composed of a capacitor component, isolating the PTC heater from the high voltage power supply. The high voltage power supply is processed into a continuously adjustable direct current through "controllable chopping + LC filtering" to drive the PTC heater. The characteristics of the inductor component in the circuit fundamentally suppress the formation of current spikes. Therefore, the upper and lower bridge arm components and the PTC heater do not need to withstand current spikes, which greatly improves the reliability of the system, fundamentally suppresses the generation of current spikes, ensures that the power tube and the PTC heater are protected from the impact of high voltage and current spikes, and works safely and reliably in a high voltage environment, thereby ensuring the safety of the PTC heater.

[0018] 2. In the present invention, the PTC heater adopts a connection method isolated from the high-voltage power supply, so that the PTC heater works in a controllable driving voltage environment, which solves the problem that the PTC heater is difficult to improve its own insulation withstand voltage level due to structural limitations, expands the application scenarios of ordinary PTC heaters in high-voltage power supply environments, meets the needs of users to upgrade high-voltage power supply systems, and facilitates the batch use of PTC heaters in actual high-voltage application environments for better results;

[0019] 3. The present invention adopts an isolated high-voltage connection method, which avoids the limitation that ordinary PTC heaters are difficult to improve the insulation withstand voltage level, expands the application scenarios of PTC heaters, saves the cost of developing high-voltage power supply systems, and facilitates PTC heaters to be suitable for new energy air-conditioning environments from low voltage to high voltage, making the application of PTC heaters more extensive and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of the PTC heater driving module A of the present invention;

[0021] Figure 2 Schematic diagram of the circuit structure of the PTC heater driving module A of the present invention;

[0022] Figure 3 This is a schematic diagram of the key circuit structure of the PTC heater driving module A of the present invention;

[0023] Figure 4 Schematic diagram of the structure of the PTC heater driving module B of the present invention;

[0024] Figure 5 Schematic diagram of the circuit structure of the PTC heater driving module B of the present invention;

[0025] Figure 6 Schematic diagram of the key circuit structure of the PTC heater driving module B of the present invention. DETAILED DESCRIPTION

[0026] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Embodiment 1

[0028] See also Figure 1 - Figure 6 The present embodiment provides a high-voltage resistant new energy automobile air conditioner PTC heater driving module, including a PTC heater driving module and a PTC heater, the PTC heater driving module including an output voltage control module, a CPU module, a driving signal module and a sampling circuit module, the driving signal module and the sampling circuit module are connected to the CPU module, the output voltage control module is electrically connected to the PTC heater, and the PTC heater driving module is composed of an output voltage control module, a CPU control module, a driving signal module and a sampling circuit module,

[0029] By designing a controllable chopper circuit and an "L" type filter circuit, the high-voltage power supply is isolated from the PTC heater, avoiding the insulation failure problem caused by direct high voltage. The high-voltage power supply is processed by the chopper circuit, and the current chopping and square wave are smoothed into direct current by a filter unit composed of an inductor component and a capacitor component, ensuring the safe and stable operation of the PTC heater in the high-voltage system. At the same time, the upper and lower bridge arm circuit structures allow flexible selection of fast diodes and power tubes according to output accuracy requirements, and the current and voltage are adjusted by the PWM duty cycle to adapt to a variety of application scenarios. At the same time, the use of power tubes improves the flexibility of PTC heater control and output accuracy.

[0030] The PTC heater drive module also includes: an upper arm chopper power tube (indicated as N1 in the figure), a lower arm freewheeling diode (indicated as D9 in the figure), an inductor component (indicated as L6 in the figure) and a capacitor component (indicated as C36 in the figure). The upper arm chopper power tube, the inductor component and the PTC heater are connected in series with each other. The inductor component and the capacitor component are arranged between the upper arm chopper power tube and the lower arm freewheeling diode to form an "L" type filter circuit. The L type filter consists of an inductor and two capacitors. The filtering effect is achieved by the combination of the inductor and the capacitor. The inductor component prevents high-frequency signals from passing through, while the capacitor component filters out high-frequency noise. When applied to the PTC heater drive module, the inductor component can prevent high-voltage current A large number of them pass through, and the capacitor component can eliminate high-frequency voltage pulses to ensure the safe use of the PTC heater drive module. The lower arm freewheeling diode and the capacitor component are connected in parallel to the series circuit of the upper arm chopper power tube, the inductor component and the PTC heater. The high-voltage power supply is first processed by the bridge chopper circuit and the "L" type filter circuit before being supplied to the PTC heater. The high-voltage power supply is isolated and directly connected to the PTC heater, so that the PTC heater of ordinary insulation level can also be used safely. This solution directly uses the upper arm chopper power tube, the lower arm freewheeling diode, the inductor component and the capacitor component to form an "L" type filter circuit. After combination, the design idea of ​​isolating high-voltage direct power supply and suppressing the biggest hidden danger, the surge current spike, is realized.

[0031] The heating circuit structure of controllable chopping + LC filtering → PTC heater is adopted to isolate the PTC heater from the high-voltage power supply, and the high-voltage power supply is processed into a continuously adjustable DC through "controllable chopping + LC filtering" to drive the PTC heater. The inductor component in the circuit fundamentally suppresses the formation of current spikes and reduces the influence of high-voltage current on the PTC heater. The PTC heater will not be impacted by the high-voltage current, which can effectively ensure the safety and stability of the use of the PTC heater.

[0032] The sampling circuit module is equipped with three groups of collection ends. The sampling circuits are respectively arranged at the input circuit end of the upper arm chopper power tube, the output circuit end of the inductor component and the negative electrode of the high-voltage power supply. When the PTC heater drive module is working, the voltage, current, resistance and other information of the circuit are collected through the collection end of the sampling circuit module, and then the collected power information is transmitted to the CPU module. Then, the control power supply module connected to the low-voltage power supply module adjusts the PTC heater drive module and adjusts the duty cycle of the PWM control signal to ensure the safe and stable use of the entire power line of the PTC heater drive module.

[0033] The drive signal module is connected to the upper arm chopper power tube. The drive signal module is the module for CPU module signal output, and the sampling circuit module is the module for CPU module signal input. The acquisition circuit module collects power information and feeds it back to the CPU module. The CPU module compiles and sends a command signal to the drive signal module. At this time, the drive signal module adjusts the duty cycle of the PWM control signal, and then adjusts the voltage output of the entire PTC heater drive module to prevent high-voltage damage to the PTC heater drive module and ensure the stable operation of the PTC heater.

[0034] The CPU module is connected to a control power module, which is connected to a low-voltage power supply module. The positive and negative electrodes of the low-voltage power supply are connected in series with the control power module. The control power module controls the power of the CPU module, the drive signal module, and the sampling circuit module. The control power module is connected to an isolation power module, and the isolation power module supplies power to the drive signal module. The isolation power module is a transformer or an optocoupler isolation element, which is used to completely isolate the input power supply from the output circuit to provide electrical safety and protection circuits. When the acquisition circuit module collects power information and feeds it back to the CPU module, and the power information is abnormal, the CPU module compiles and sends a command signal to the drive signal module, and the drive signal module adjusts the duty cycle of the PWM control signal. At this time, when the duty cycle of the PWM control signal is invalid, the isolation power module will isolate the circuit by voltage conversion to ensure the safety of the entire PTC heater drive module, prevent damage to the PTC heater drive module due to abnormal circuits, and ensure the safety of components of the PTC heater drive module.

[0035] The CPU module is connected to a communication module, which is provided with a connection interface. The communication module communicates with external equipment through a wired connection. The PTC heater driving module is provided with a shell, the PTC heater is arranged outside the shell, and the PTC heater is connected to the PTC heater driving module through a wired connection. The communication module interface and the low-voltage power supply module interface are integrated together, and then the high-voltage power supply module is separately provided with a connection interface. The above interface and the PTC heater interface are both provided on the shell.

[0036] Embodiment 2

[0037] See also Figure 4 and Figure 6 , further improvements are made on the basis of the first embodiment:

[0038] The upper arm chopper power tube is one of an IGBT tube, a silicon carbide tube and a MOS tube, preferably a silicon carbide tube here, the lower arm freewheeling diode is a fast diode, the position of the lower arm freewheeling diode can be replaced by a lower arm freewheeling power tube (indicated as N2 in the figure), the lower arm freewheeling power tube is one of an IGBT tube, a silicon carbide tube and a MOS tube, preferably a silicon carbide tube here, the circuit structure of the PTC heater drive module has two sets of schemes, the difference between the two circuit solutions is that the application of the lower arm freewheeling diode and the lower arm freewheeling power tube is different (refer to Figure 1 and Figure 4 ), the two design schemes have the same working principle. The difference is that the use of the lower arm freewheeling diode can reduce the cost of the circuit and simplify one PWM control signal and its peripheral auxiliary circuits, while the use of the lower arm freewheeling power tube requires an additional PWM control signal and its peripheral auxiliary circuits, thereby increasing the cost of the PTC heater drive module. However, it can also improve the performance of the PTC heater drive module and improve its response to high-voltage environments. Therefore, the two circuit solutions need to be selected according to the actual application scenarios of new energy vehicle air conditioners and other factors.

[0039] Specifically, the upper and lower bridge arm circuits are composed of an upper arm chopper power tube and a lower arm freewheeling diode (or a lower arm freewheeling power tube), and an "L" type filter circuit composed of an inductor component and a capacitor component is connected to the midpoint of the upper and lower bridge arms. Then, the duty cycle of the PWM control signal is adjusted to control the upper arm chopper power tube and the lower arm freewheeling diode circuit to chop the high voltage power supply, and then the "L" type filter circuit filters the square wave formed by the chopping to form a smooth DC power supply output with adjustable amplitude, which is used to power the PTC heater.

[0040] By adjusting the duty cycle of the PWM control signal, the chopping frequency of the bridge arm is controlled, and the "L" type filter circuit is used for filtering, the PTC heater output is driven with continuously adjustable current and voltage to avoid frequent power on and off driving, thereby avoiding transient current spikes. It also makes the components on the upper and lower bridge arms no longer need to withstand current spikes, and work in a safe environment, greatly improving reliability.

[0041] During operation, the upper and lower bridge arms are turned on alternately, the upper arm chopper power tube performs current chopping, and the lower arm freewheeling diode (or lower arm freewheeling power tube) performs current freewheeling, storing energy and charging the inductor and capacitor components. Due to the characteristics of the inductor components, the circuit will not generate surge peak current during operation. The lower bridge arm uses a lower arm freewheeling diode, which uses the unidirectional conductivity of the diode for freewheeling. This can simplify one PWM control signal and its surrounding auxiliary circuits, and can also meet the use requirements. In the use environment with high output accuracy requirements, the lower bridge arm can use the lower arm freewheeling power tube to assume the freewheeling role. Using the lower arm freewheeling power tube as the lower bridge arm requires adding one PWM control signal and corresponding auxiliary circuit components.

[0042] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-voltage resistant new energy automobile air conditioner PTC heater drive module, comprising a PTC heater drive module and a PTC heater, characterized in that: The PTC heater driving module includes an output voltage control module, a CPU control module, a drive signal module and a sampling circuit module, which are composed of a chopper freewheeling circuit composed of upper and lower bridge arms and an "L" type filter. The drive signal module and the sampling circuit module are connected to the CPU module, and the output voltage control module is electrically connected to the PTC heater. The PTC heater driving module is composed of an output voltage control module, a CPU control module, a drive signal module and a sampling circuit module. The output voltage control module is composed of N1, D9, L6, and C36; the CPU control module is composed of a single-chip microcomputer and its peripheral power supply and auxiliary circuits; the driving module is composed of a bridge arm driving circuit and an isolated power supply; the sampling circuit module is composed of an input voltage sampling circuit, an output voltage sampling circuit, a current sampling circuit, and a number of temperature sampling circuits; The PTC heater driving module also includes: an upper arm chopper power tube, a lower arm freewheeling diode, an inductor component and a capacitor component. The upper arm chopper power tube, the inductor component and the PTC heater are connected in series with each other, and the lower arm freewheeling diode and the capacitor component are connected in parallel to the series circuit of the upper arm chopper power tube, the inductor component and the PTC heater.

2. A high-voltage resistant new energy automobile air conditioner PTC heater drive module according to claim 1, characterized in that: The sampling circuit module is provided with three groups of acquisition terminals, and the sampling circuits are respectively arranged at the input circuit terminal of the upper arm chopper power tube, the output circuit terminal of the inductor component and the negative electrode of the high-voltage power supply.

3. A high-voltage resistant new energy automobile air conditioner PTC heater drive module according to claim 1, characterized in that: The drive signal module is connected in series with the upper arm chopper power tube, the drive signal module is a module for outputting signals from the CPU module, and the sampling circuit module is a module for inputting signals from the CPU module.

4. A high-voltage resistant new energy automobile air conditioner PTC heater drive module according to claim 1, characterized in that: The CPU module is connected to a control power module, which is connected to a low-voltage power supply module. The low-voltage power supply positive electrode and the low-voltage power supply negative electrode are connected in series with the control power module. The control power module controls the power of the CPU module, the drive signal module, and the sampling circuit module.

5. A high-voltage resistant new energy automobile air conditioner PTC heater drive module according to claim 4, characterized in that: The control power module is connected to an isolation power module, and the isolation power module supplies power to the drive signal module.

6. A high-voltage resistant new energy automobile air conditioner PTC heater drive module according to claim 1, characterized in that: The CPU module is connected to a communication module, the communication module is provided with a connection interface, and the communication module communicates with an external device via a wired connection.

7. A high-voltage-resistant new energy automobile air conditioner PTC heater drive module according to claim 1, characterized in that: The PTC heater driving module is provided with a shell, the PTC heater is arranged outside the shell, and the PTC heater is connected to the PTC heater driving module through a wire.

8. A high-voltage-resistant new energy automobile air conditioner PTC heater drive module according to claim 1, characterized in that: The inductor component and the capacitor component are arranged between the upper arm chopper power tube and the lower arm freewheeling diode to form an "L" type filtering circuit.

9. A high-voltage-resistant new energy automobile air conditioner PTC heater drive module according to claim 1, characterized in that: The upper arm chopper power tube is one of an IGBT tube, a silicon carbide tube and a MOS tube, and is preferably a silicon carbide tube.

10. A high-voltage-resistant new energy automobile air conditioner PTC heater drive module according to claim 1, characterized in that: The lower arm freewheeling diode is a fast diode, and the position of the lower arm freewheeling diode can be replaced by a lower arm freewheeling power tube. The lower arm freewheeling power tube is one of an IGBT tube, a silicon carbide tube and a MOS tube, and the silicon carbide tube is preferably used here.

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