A pre-charge module for a water heater controller

Abstract

The present invention discloses a pre-charging module of a water heater controller, which includes a driving module, an operational amplifier U552 connected to the driving module, and an IGBT transistor Q552 connected to the operational amplifier U552. Through the self-hardware characteristics of the IGBT and by using a low-power resistor (1W), the pre-charging circuit design of the present invention successfully performs constant-current charging on the filter capacitor; through the logical control of software, the IGBT is well protected to prevent overheating and burning caused by the self-hardware turn-off of the IGBT; the constant-current pre-charging of the pre-charging module truly achieves the protection of capacitor charging.

Description

Technical Field

[0001] The present invention relates to the field of automotive water heaters, and particularly to a pre-charge module of a water heater controller. Background Art

[0002] Automotive heaters are mainly used to preheat the engine in winter and provide heating for the cab of a freight vehicle or the passenger compartment of a bus. In the traditional setting of an automotive water heater, the filter capacitor is directly set at the rear end of the IGBT in the water heater controller and is directly connected to high voltage electricity. In this way, when the IGBT tube conducts, there will be a large charging current in the filter capacitor (the capacitor can be regarded as a short circuit state when in the charging state). The excessive charging current will cause the following two impacts: the charging current value exceeds the IGBT transient current upper limit value (60 A), and the IGBT tube is broken down into a short circuit state; the excessive charging current may be fed back to the IGBT drive module end, causing the drive module to turn off the IGBT tube. The phenomena caused by the excessive charging current will make the product not work or pose a risk of high voltage short circuit to the whole vehicle. This traditional design greatly reduces the service life of the filter capacitor, and there is also a risk of high voltage short circuit in the vehicle. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a pre-charge module of a water heater controller to prevent the filter capacitor of the product from being directly connected to high voltage electricity, greatly increase the service life of the filter capacitor, and reduce the risk of high voltage short circuit in the vehicle.

[0004] The technical solution adopted by the present invention to solve the above problems is: a pre-charge module of a water heater controller, including a drive module, an operational amplifier U552 connected to the drive module, and an IGBT tube Q552 connected to the operational amplifier U552.

[0005] The 14th pin of the operational amplifier U552 is connected to the G pole of the IGBT tube Q552 through a resistor R552. The C pole of the IGBT tube Q552 is connected to the output terminal HV+. The E pole of the IGBT tube Q552 is connected to the output terminal HV+Prot through a resistor R556. The G pole of the IGBT tube Q552 is connected to the output terminal HV+Prot through a resistor R553 and a resistor R555.

[0006] The 11th pin of the operational amplifier U552 is connected to the 1st pin of an operational amplifier U551. The 2nd pin of the operational amplifier U551 is connected to the reference ground HSS_COM terminal. The 3rd pin of the operational amplifier U551 is connected to the reference ground HSS_COM terminal through a resistor R558. A capacitor C557 is connected in parallel with the resistor R558. The 3rd pin of the operational amplifier U551 is connected to a resistor R552 through a resistor R554. The 4th pin of the operational amplifier U551 is connected to the E pole of the IGBT transistor Q552. The E pole of the IGBT transistor Q552 is connected to the connection terminal of a resistor R553 and a resistor R555. The 5th pin of the operational amplifier U551 is connected to the +15V_HV_HSS terminal and is connected to the reference ground HSS_COM terminal through a capacitor C553;

[0007] The 11th pin of the operational amplifier U552 is connected to the +5V_HV_HSS terminal through a resistor R559.

[0008] Compared with the prior art, the advantages of the present invention are as follows: The design of the pre-charge circuit uses the self-hardware characteristics of the IGBT and successfully charges the filter capacitor with a constant current by using a low-power resistor (1W); through the logical control of the software, the IGBT is well protected to prevent the IGBT from overheating and burning due to its own hardware turn-off; the constant-current pre-charge of the pre-charge module truly achieves the protection of capacitor charging.

[0009] Preferably, a triode Q551A and a triode Q551B are further provided between the 14th pin of the operational amplifier U552 and the resistor R552. The 14th pin of the operational amplifier U552 is connected to the B pole of the triode Q551A. The E pole of the triode Q551A is connected to the reference ground HSS_COM terminal. The C pole of the triode Q551A is connected to the B pole of the triode Q551B. The C pole of the triode Q551B is connected to the resistor R552. The E pole of the triode Q551B is connected to the +15V_HV_HSS terminal.

[0010] Preferably, the triode Q551A and the triode Q551B are integrated in a first chip, and the model of the first chip is EMD12FHA.

[0011] Preferably, the model of the operational amplifier U552 is Si8641BB-AS1.

[0012] Preferably, the C pole of the IGBT transistor Q552 is connected to the C pole of an IGBT transistor Q554. The G pole of the IGBT transistor Q554 is connected to the E pole of the IGBT transistor Q554 through a resistor R564. A capacitor C559 is also connected in parallel at both ends of the resistor R564. The E pole of the IGBT transistor Q554 is connected to the output terminal HV+Prot;

[0013] The 11th pin of the operational amplifier U552 is connected to the B pole of a triode Q555B. The C pole of the triode Q555B is connected to the B pole of a triode Q553A. The C pole of the triode Q553A is connected to the B pole of a triode Q553B. The E poles of the triode Q555B and the triode Q553A are both connected to the reference ground HSS_COM terminal. The E pole of the triode Q553B is connected to the +15V_HV_HSS terminal. The C pole of the triode Q553B is connected to the G pole of the IGBT tube Q554 through a resistor R562;

[0014] The 13th pin of the operational amplifier U552 is connected to the B pole of the triode Q553A through a resistor R561.

[0015] Preferably, the C pole of the IGBT tube Q552 is connected to the C pole of an IGBT tube Q557. The G pole of the IGBT tube Q557 is connected to the E pole of the IGBT tube Q557 through a resistor R568. A capacitor C562 is also connected in parallel across both ends of the resistor R568. The E pole of the IGBT tube Q557 is connected to the output terminal HV+Prot. The E pole of the IGBT tube Q557 is also connected to the reference ground HSS_COM terminal;

[0016] The 11th pin of the operational amplifier U552 is connected to the B pole of a triode Q555A. The C pole of the triode Q555A is connected to the B pole of a triode Q556A. The C pole of the triode Q556A is connected to the B pole of a triode Q556B. The E poles of the triode Q555A and the triode Q556A are both connected to the reference ground HSS_COM terminal. The E pole of the triode Q556B is connected to the +15V_HV_HSS terminal. The C pole of the triode Q556B is connected to the G pole of the IGBT tube Q554 through a resistor R567;

[0017] The 12th pin of the operational amplifier U552 is connected to the B pole of the triode Q556A through a resistor R566.

[0018] Preferably, the triode Q555A and the triode Q555B are integrated in a second chip, and the model of the second chip is PEMH2;

[0019] The triode Q553A and the triode Q553B are integrated in a third chip. The triode Q556A and the triode Q556B are integrated in a fourth chip. The models of the third chip and the fourth chip are both EMD12FHA. Description of the Drawings

[0020] Figure 1 Overall structural schematic diagram of the pre-charge module circuit of the water heater controller of the present invention;

[0021] Figure 2 Schematic diagram of the pre-charge module circuit of the water heater controller of the present invention;

[0022] Figure 3 Schematic diagram of the circuit structure of the drive module in the pre-charge module of the water heater controller of the present invention;

[0023] Figure 4 Schematic diagram of the saturation voltage of the IGBT tube of the present invention;

[0024] Figure 5 Measured voltage value of the IGBT tube of the present invention;

[0025] Figure 6 Measured chart of the charging time of the pre-charge module of the present invention;

[0026] Figure 7 Schematic diagram of monitoring the HV terminal current, U551_PIN11 pin, and U551_PIN14 pin of the product of the present invention. Detailed implementation manners

[0027] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0028] As Figures 1-3 shown, this embodiment relates to a pre-charge module of a water heater controller, which includes a drive module, an operational amplifier U552 connected to the drive module, and an IGBT tube Q552 connected to the operational amplifier U552.

[0029] In this embodiment, the 14th pin of the operational amplifier U552 is connected to the G pole of the IGBT tube Q552 through a resistor R552, the C pole of the IGBT tube Q552 is connected to the output terminal HV+, the E pole of the IGBT tube Q552 is connected to the output terminal HV+Prot through a resistor R556, and the G pole of the IGBT tube Q552 is connected to the output terminal HV+Prot through a resistor R553 and a resistor R555.

[0030] Specifically, the signal of the 14th pin of the operational amplifier U552 is weak and needs to be amplified to control the IGBT tube. Therefore, a triode Q551A and a triode Q551B are also provided between the 14th pin of the operational amplifier U552 and the resistor R552. The 14th pin of the operational amplifier U552 is connected to the B pole of the triode Q551A, the E pole of the triode Q551A is connected to the reference ground HSS_COM terminal, the C pole of the triode Q551A is connected to the B pole of the triode Q551B, the C pole of the triode Q551B is connected to the resistor R552, and the E pole of the triode Q551B is connected to the +15V_HV_HSS terminal.

[0031] Among them, the triode Q551A and the triode Q551B are integrated in the first chip, and the model of the first chip is EMD12FHA. The model of the operational amplifier U552 is Si8641BB-AS1.

[0032] In this embodiment, a feedback module circuit is provided, which specifically includes the following: The 11th pin of the operational amplifier U552 is connected to the 1st pin of an operational amplifier U551. The 2nd pin of the operational amplifier U551 is connected to the reference ground HSS_COM terminal. The 3rd pin of the operational amplifier U551 is connected to the reference ground HSS_COM terminal through a resistor R558, and a capacitor C557 is connected in parallel with the resistor R558. The 3rd pin of the operational amplifier U551 is connected to the resistor R552 through a resistor R554. The 4th pin of the operational amplifier U551 is connected to the E pole of the IGBT tube Q552. The E pole of the IGBT tube Q552 is connected to the connection terminal of the resistor R553 and the resistor R555. The 5th pin of the operational amplifier U551 is connected to the +15V_HV_HSS terminal and is connected to the reference ground HSS_COM terminal through a capacitor C553.

[0033] Among them, the 11th pin of the operational amplifier U552 is connected to the +5V_HV_HSS terminal through a pull-up resistor R559.

[0034] In this embodiment, the C pole of the IGBT tube Q552 is connected to the C pole of an IGBT tube Q554. The G pole of the IGBT tube Q554 is connected to the E pole of the IGBT tube Q554 through a resistor R564, and a capacitor C559 is also connected in parallel across both ends of the resistor R564. The E pole of the IGBT tube Q554 is connected to the output terminal HV+Prot;

[0035] The 11th pin of the operational amplifier U552 is connected to the B pole of a triode Q555B. The C pole of the triode Q555B is connected to the B pole of a triode Q553A. The C pole of the triode Q553A is connected to the B pole of a triode Q553B. The E poles of the triode Q555B and the triode Q553A are both connected to the reference ground HSS_COM terminal. The E pole of the triode Q553B is connected to the +15V_HV_HSS terminal. The C pole of the triode Q553B is connected to the G pole of the IGBT tube Q554 through a resistor R562;

[0036] The 13th pin of the operational amplifier U552 is connected to the B pole of the triode Q553A through a resistor R561.

[0037] In this embodiment, the C electrode of IGBT transistor Q552 is connected to the C electrode of an IGBT transistor Q557. The G electrode of IGBT transistor Q557 is connected to the E electrode of IGBT transistor Q557 through a resistor R568. A capacitor C562 is also connected in parallel across both ends of resistor R568. The E electrode of IGBT transistor Q557 is connected to the output terminal HV+Prot, and the E electrode of IGBT transistor Q557 is also connected to the reference ground HSS_COM terminal.

[0038] The 11th pin of operational amplifier U552 is connected to the B electrode of a triode Q555A. The C electrode of triode Q555A is connected to the B electrode of a triode Q556A. The C electrode of triode Q556A is connected to the B electrode of a triode Q556B. The E electrodes of both triode Q555A and triode Q556A are connected to the reference ground HSS_COM terminal. The E electrode of triode Q556B is connected to the +15V_HV_HSS terminal. The C electrode of triode Q556B is connected to the G electrode of IGBT transistor Q554 through a resistor R567.

[0039] In this embodiment, the 12th pin of operational amplifier U552 is connected to the B electrode of triode Q556A through a resistor R566. Triode Q555A and triode Q555B are integrated in the second chip, and the model of the second chip is PEMH2.

[0040] Triode Q553A and triode Q553B are integrated in the third chip, and triode Q556A and triode Q556B are integrated in the fourth chip. The models of both the third chip and the fourth chip are EMD12FHA.

[0041] In this embodiment, the circuit structure of the drive module is as follows: The 1st pin of operational amplifier U552 is connected to the +5V_HV terminal; the 2nd pin is connected to the GND_HV terminal; the 3rd pin is connected to the input terminal DoHssPreChargeEn through a resistor R557, and at the same time, the 3rd pin is also connected to the GND_HV terminal through a capacitor C554; the 4th pin is connected to the input terminal DoHss1En through a resistor R560, and at the same time, the 4th pin is also connected to the GND_HV terminal through a capacitor C558; the 5th pin is connected to the input terminal DoHss2En through a resistor R563, and at the same time, the 5th pin is also connected to the GND_HV terminal through a capacitor C560; the 6th pin is connected to the input terminal DiFilterPrecharge through a resistor R565. The drive module also includes an input terminal Shdn. The input terminal Shdn is connected to the 3rd pin of power amplifier U552 through a diode D552; the input terminal Shdn is connected to the 4th pin of power amplifier U552 through a diode D553; the input terminal Shdn is connected to the 5th pin of power amplifier U552 through a diode D554.

[0042] In this embodiment, the 9th and 15th pins of the operational amplifier U552 are connected to the reference ground HSS_COM terminal, and the 10th and 16th pins are connected to the +5V_HV_HSS terminal.

[0043] In this embodiment, before starting the heating operation, the product initialization control logic is as follows:

[0044] 1 - First, send the state (high level) of the input terminal DoHssPreChargeEn = 1.

[0045] 2 - Detect that the input terminal DiFilterPrecharge flag bit is high level, and wait for 2 ms (in actual test, this pin is high level as soon as it is powered on).

[0046] 3 - Detect that the input terminal DiFilterPrecharge flag bit is low level, and wait for 150 ms (in actual test, when the charging is completed approximately at 45 ms, the flag bit becomes low).

[0047] 4 - Turn on HSS1 and HSS2, high-side IGBT.

[0048] Among them, the verification test steps for the product-side designed pre-charge module are as follows:

[0049] 1 - Product initialization control logic.

[0050] 2 - Monitor the 14th and 11th pins of U552. When the high-voltage power supply HV = 280 and there is no power requirement. PIN14 = 0V (no requested power is sent), PIN11 = 5V (since both PIN3 and PIN4 have no input, so PIN1 has no output, and it is the 5V pull-up resistor that clamps PIN11 at 5V).

[0051] 3 - The measured voltage of HV_+15V_HSS is designed to be 15.6V.

[0052] 4 - When the voltage at the Vge terminal of the IGBT tube Q552 is greater than 7V, the CE terminals of the IGBT tube Q552 start to conduct. When Vge is less than 7V, the CE terminals start to turn off.

[0053] As Figures 4-5 shown, the actual test values: in the state where there is no capacitor at the Vge terminal, Delaytostartswitchon[AB]<200ns, VGEth[B]≈7V.

[0054] 5 - Test the charging time of the product pre-charge module (HSS_COM is equivalent to HV_port).

[0055] As Figure 6As shown, this figure shows the measured values. The upper line in the figure is the G-terminal voltage of the pre-charge IGBT transistor Q552, and the lower line in the figure is the HSS_COM voltage value. It can be seen that the time required for the product side to charge the capacitor to 280V is about 40ms.

[0056] 6 - Theoretical verification that the time required for the product pre-charge module to charge the capacitor to 280V is 40ms.

[0057] As Figure 7 shown, monitor the HV terminal current of the product, the U551_PIN11 pin, and the U551_PIN14 pin.

[0058] It can be seen that after about 40ms, the PIN11 pin is turned off and becomes low level. This event is consistent with the charging time of the pre-charged capacitor, and it can be confirmed that the actual charging time of the capacitor is between 40 and 45ms.

[0059] The current at the HV terminal is constantly current charging in the pre-charge state. The constantly current charging current is 82mA (point b in the figure), and when the PIN11 pin changes from on to off instantaneously (point a in the figure), the current at the HV terminal is 14mA.

[0060] 7 - When pre-charge is applied to the X capacitor, since the capacitor can be regarded as a short circuit state at the beginning of charging the X capacitor, so I transient = 280V / 100Ω = 2.8A. When the current through the 100R resistor is greater than 90mA (estimated value), the voltage of Vge = 15.6 - 9V = 6.6V < the switching condition of Vge, so the IGBT transistor Q552 will turn off. After the IGBT transistor Q552 turns off, the current flowing through the resistor R100 will decrease instantaneously. When it is less than 82mA, Vge = 15.6V - 8.2V = 7.4V > the switching condition of Vge, causing the IGBT transistor Q552 to start switching again. Therefore, the IGBT transistor Q552 enters the switching state back and forth at the ns level, resulting in the current oscillation through the resistor R100 being maintained at 82mA.

[0061] When the reverse voltage of the PIN3 pin of the operational amplifier U551: (15.6V * 1.2KΩ) / 11.2KΩ = 1.67V. So the theoretical value is that when the current through the 100R resistor is less than 16.7mA, the operational amplifier will output a low level. It can be seen from the HV current waveform that when the current is 14mA, the operational amplifier outputs a low level voltage, and the test conforms to the theoretical value.

[0062] And calculate whether the charging time is 45 ms: Q = CU = IT → T = (13.2 μF * 280 V) / 82 mA = 45 ms. This calculated value is consistent with the test value. And according to the calculation, whether two 200-ohm resistors can meet this requirement during the capacitor charging. W = I² * R = 0.82 * 0.82 * 100 = 67.24 = 0.67 W. The power consumption of each resistor can withstand 0.5 W, and a total of 0.5 * 2 = 1 W can be withstood. So the selection of the resistor meets the requirements.

[0063] This embodiment solves the problem of insufficient service life of the filtering capacitor at the high-voltage end of the product. (The whole vehicle has a 15-year quality assurance); it solves the problem of the high-voltage current bearing capacity of the pre-charge module when it first enters the charging mode; combined with software control design, it effectively detects and manages the pre-charge module to prevent failure phenomena.

[0064] The beneficial effects of the present invention are as follows: The design of the pre-charge circuit, through the inherent hardware characteristics of the IGBT, successfully charges the filtering capacitor with a constant current by using a low-power resistor (1 W); through the logical control of the software, the IGBT is well protected to prevent overheating and burnout caused by the opening and closing of the IGBT's own hardware; the constant-current pre-charge of the pre-charge module truly achieves the protection of capacitor charging.

[0065] The above description shows and describes several preferred embodiments of the present invention. However, as mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the inventive concept described herein through the above teachings or the technology or knowledge in related fields. And any changes and modifications made by those skilled in the art without departing from the spirit and scope of the present invention shall fall within the protection scope of the appended claims of the present invention.

Claims

1. A pre-charge module of a water heater controller, comprising a driving module, an operational amplifier U552 connected to the driving module, and an IGBT transistor Q552 connected to the operational amplifier U552, characterized in that: The 14th pin of the operational amplifier U552 is connected to the G pole of the IGBT transistor Q552 through a resistor R552. The C pole of the IGBT transistor Q552 is connected to the output terminal HV+. The E pole of the IGBT transistor Q552 is connected to the output terminal HV+Prot through a resistor R556. The G pole of the IGBT transistor Q552 is connected to the output terminal HV+Prot through a resistor R553 and a resistor R555. The 11th pin of the operational amplifier U552 is connected to the 1st pin of an operational amplifier U551. The 2nd pin of the operational amplifier U551 is connected to the reference ground HSS_COM terminal. The 3rd pin of the operational amplifier U551 is connected to the reference ground HSS_COM terminal through a resistor R558. A capacitor C557 is connected in parallel with the resistor R558. The 3rd pin of the operational amplifier U551 is connected to the resistor R552 through a resistor R554. The 4th pin of the operational amplifier U551 is connected to the E pole of the IGBT transistor Q552. The E pole of the IGBT transistor Q552 is connected to the connection terminal of the resistor R553 and the resistor R555. The 5th pin of the operational amplifier U551 is connected to the +15V_HV_HSS terminal and is connected to the reference ground HSS_COM terminal through a capacitor C553. The 11th pin of the operational amplifier U552 is connected to the +5V_HV_HSS terminal through a resistor R559. A triode Q551A and a triode Q551B are further provided between the 14th pin of the operational amplifier U552 and the resistor R552. The 14th pin of the operational amplifier U552 is connected to the B pole of the triode Q551A. The E pole of the triode Q551A is connected to the reference ground HSS_COM terminal. The C pole of the triode Q551A is connected to the B pole of the triode Q551B. The C pole of the triode Q551B is connected to the resistor R552. The E pole of the triode Q551B is connected to the +15V_HV_HSS terminal. The model of the operational amplifier U552 is Si8641BB-AS1.

2. The pre-charging module of a water heater controller according to claim 1, wherein: The triode Q551A and the triode Q551B are integrated in a first chip, and the model of the first chip is EMD12FHA.

3. The pre-charging module of a water heater controller according to claim 1, characterized in that: The C pole of the IGBT transistor Q552 is connected to the C pole of an IGBT transistor Q554. The G pole of the IGBT transistor Q554 is connected to the E pole of the IGBT transistor Q554 through a resistor R564. A capacitor C559 is also connected in parallel at both ends of the resistor R564. The E pole of the IGBT transistor Q554 is connected to the output terminal HV+Prot. The 11th pin of the operational amplifier U552 is connected to the base of a triode Q555B. The collector of the triode Q555B is connected to the base of a triode Q553A. The collector of the triode Q553A is connected to the base of a triode Q553B. The emitters of the triode Q555B and the triode Q553A are both connected to the reference ground HSS_COM terminal. The emitter of the triode Q553B is connected to the +15V_HV_HSS terminal. The collector of the triode Q553B is connected to the gate of the IGBT tube Q554 through a resistor R562; The 13th pin of the operational amplifier U552 is connected to the base of the triode Q553A through a resistor R561.

4. The pre-charging module of a water heater controller according to claim 3, characterized in that: The collector of the IGBT tube Q552 is connected to the collector of an IGBT tube Q557. The gate of the IGBT tube Q557 is connected to the emitter of the IGBT tube Q557 through a resistor R568. A capacitor C562 is also connected in parallel across both ends of the resistor R568. The emitter of the IGBT tube Q557 is connected to the output terminal HV+Prot. The emitter of the IGBT tube Q557 is also connected to the reference ground HSS_COM terminal; The 11th pin of the operational amplifier U552 is connected to the base of a triode Q555A. The collector of the triode Q555A is connected to the base of a triode Q556A. The collector of the triode Q556A is connected to the base of a triode Q556B. The emitters of the triode Q555A and the triode Q556A are both connected to the reference ground HSS_COM terminal. The emitter of the triode Q556B is connected to the +15V_HV_HSS terminal. The collector of the triode Q556B is connected to the gate of the IGBT tube Q554 through a resistor R567; The 12th pin of the operational amplifier U552 is connected to the base of the triode Q556A through a resistor R566.

5. The pre-charging module of a water heater controller according to claim 4, characterized in that: The triode Q555A and the triode Q555B are integrated in a second chip, and the model of the second chip is PEMH2; The triode Q553A and the triode Q553B are integrated in a third chip, and the triode Q556A and the triode Q556B are integrated in a fourth chip. The models of the third chip and the fourth chip are both EMD12FHA.

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