High-power current-limiting resistor circuit for pre-charging

Abstract

The invention discloses a high-power current-limiting resistor circuit for pre-charging. The pre-charge circuit may include a switching device for controlling a voltage to be supplied to the battery, and a current limiting resistor circuit coupled to the switching device. The current limiting resistor circuit may include a positive temperature coefficient (PTC) component arranged in electrical series with the switching device.

Description

Technical Field

[0001] Embodiments relate to the field of resistive heaters, and more particularly to pre-charge circuit protection. Background Art

[0002] Today, battery-powered electric vehicles (EVs) may include controllers with high capacitive loads that may be used to regulate the motor. High voltage (HV) positive and negative contactors are used in EVs to act as emergency disconnects in the event of a motor regulator failure. In today's EVs, soft start auxiliary circuits may be used to ensure proper operation of the battery circuit. However, such circuits may be overly complex and expensive.

[0003] It is with respect to this and other considerations that the present disclosure is provided. Summary of the invention

[0004] In one embodiment, a precharge circuit is provided. The precharge circuit may include a switching device for controlling a voltage to be supplied to a battery, and a current limiting resistor circuit coupled to the switching device. The current limiting resistor circuit may include a positive temperature coefficient (PTC) component electrically arranged in series with the switching device.

[0005] In another embodiment, a battery circuit is provided, comprising a first terminal line for connecting an external component to a first terminal of a battery. The battery circuit may include a first main contactor connected in series along the first terminal line, and a precharge circuit connected between the first terminal and the external component along a precharge path extending in parallel with the first main contactor. The precharge circuit may include a switching device, and a current limiting resistor circuit electrically coupled to the switching device in series, wherein the current limiting resistor circuit includes a positive temperature coefficient (PTC) component, which is arranged electrically in series with the switching device.

[0006] In another embodiment, a method for managing current flow in an electronic circuit is provided. The method may include providing a battery circuit, the battery circuit including a first terminal line for connecting an external component to a first terminal of a battery, a first main contactor connected in series along the first terminal line, a second terminal line for connecting an external component to a second terminal of the battery, a second main contactor connected in series along the second terminal line, and a pre-charge circuit. The pre-charge circuit may be connected between the first terminal and the external component along a pre-charge path extending in parallel with the first main contactor. The method may also include maintaining the first main contactor and the second main contactor in an open position during a first state, placing the second main contactor in a closed position during a pre-charge state and allowing current to flow through the pre-charge circuit, and closing the first main contactor while maintaining the second main contactor in a closed position during a charging state. Therefore, the pre-charge circuit may include a switching device; and a current limiting resistor circuit, which includes a positive temperature coefficient (PTC) component arranged in series with the switching device. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1A An electronic circuit according to an embodiment of the present disclosure is shown;

[0008] Figure 1B Another electronic circuit according to an embodiment of the present disclosure is shown;

[0009] Figure 1C shows a further electronic circuit according to an embodiment of the present disclosure;

[0010] Figure 2 Additional electronic circuitry according to an embodiment of the present disclosure is shown;

[0011] Figure 3A The embodiment according to the present disclosure is shown when operating under the first capacitor charging condition Figure 2 An electronic circuit is a set of experimental capacitors charged against voltage and current;

[0012] Figure 3B-3D Shows Figure 3A Details;

[0013] Figure 4A A reference electronic circuit is shown;

[0014] Figure 4B shows the second capacitor charging condition Figure 4A The calculated capacitor charge of the reference circuit;

[0015] Figure 4C shows that under the second capacitor charging condition Figure 4A The reference circuit calculates the capacitor charging for voltage and current;

[0016] Figure 5A Another electronic circuit according to an embodiment of the present disclosure is shown;

[0017] Figure 5B The following diagram shows the circuit breaker under the untripped condition according to the second capacitor charging condition. Figure 5A Experimental results of pulse charging test of electronic circuits;

[0018] Figure 5C FIG. 2 shows a protection mode triggered by an extended charging time according to a second capacitor charging condition. Figure 5A Experimental results on the behavior of electronic circuits;

[0019] Figure 6 Another reference circuit is shown;

[0020] Fig. 6A shows the third capacitor charging condition Figure 6 The calculated capacitor charge of the reference circuit;

[0021] Figure 6B shows that under the third capacitor charging condition according to Figure 6 The reference circuit calculates the voltage and current for the capacitor charging;

[0022] Fig. 7A Another circuit according to an additional embodiment of the present disclosure is shown;

[0023] Figure 7B An exemplary pulse waveform is shown;

[0024] Figure 7C shows the protection mode triggered by the extended charging time Fig. 7A An image of a circuit;

[0025] Figure 8 A further reference circuit is shown;

[0026] Fig. 8A Shows the use of Figure 8 the electronic circuitry for a calculated capacitor charge for a fourth capacitor charging scenario;

[0027] Figure 8B shows that in the fourth capacitor charging scenario according to Fig. 8A An electronic circuit calculates the voltage against which a capacitor is charged;

[0028] Figure 8C shows that in the fourth capacitor charging scenario according to Fig. 8A An electronic circuit calculates the current for charging a capacitor;

[0029] Fig. 9A shows a further electronic circuit according to an embodiment of the present disclosure;

[0030] Fig. 9B Shows the non-tripped condition Figure 8 Experimental results of pulse charging test of electronic circuits;

[0031] Fig. 9C shows the protection mode triggered by the extended charging time Fig. 9A images of electronic circuits; and

[0032] Fig.10 An exemplary process flow is depicted. DETAILED DESCRIPTION

[0033] The present embodiment will now be described more fully below with reference to the accompanying drawings, which illustrate exemplary embodiments. The embodiments should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey their scope to those skilled in the art. In the accompanying drawings, the same numbers refer to the same elements throughout.

[0034] In the following description and / or claims, the terms "on", "covering on ...", "disposed on ...", and "above" may be used in the following description and claims. "On", "covering on ...", "disposed on ...", and "above" may be used to indicate that two or more elements are in direct physical contact with each other. In addition, the terms "on", "covering on ...", "disposed on ...", and "above" may mean that two or more elements are not in direct contact with each other. For example, "above" may mean that one element is above another element without contacting each other and may have another one or more elements between the two elements. In addition, the term "and / or" may mean "and", it may mean "or", it may mean "exclusive-or", it may mean "one", it may mean "some but not all", it may mean "neither", and / or it may mean "both", although the scope of the claimed subject matter is not limited in this respect.

[0035] In various embodiments, a set of novel pre-charge circuits are provided for protecting battery circuits. The novel pre-charge circuits of the present embodiment can be used to manage current flow in electronic circuits including battery circuits. Suitable applications of the pre-charge circuits of the present embodiment include battery circuits of electric vehicles. The battery can be used to power various loads or components (including motors) in electric vehicles.

[0036] Steering Figure 1A, which shows an electronic circuit 100 according to an embodiment of the present disclosure. The electronic circuit 100 may include a first terminal line 126 for connecting an external component (such as a motor) to a first terminal 120A of a battery 120. The electronic circuit 100 may also include a first main contactor 122 connected in series along the first terminal line 126. In this example, the first terminal line 126 is connected to the positive terminal of the battery 120. The electronic circuit 100 may also include a second terminal line 128 for connecting an external component to a second terminal 120B of the battery 120, and a second main contactor 124 connected in series along the second terminal line 128. When closed, the first main contactor 122 and the second main contactor 124 will complete the circuit, which couples the battery 120 to drive one or more external components, such as one or more motors. Similarly, when closed, the first main contactor 122 and the second main contactor 124 will complete the circuit to allow the battery 120 to be charged. The electronic circuit 100 may also include a component referred to as a pre-charge circuit 102 connected between the first terminal 120A and one or more external components (eg, see motor controller 134 and load as examples of external components) along a pre-charge path 130 extending in parallel with the first main contactor 122 .

[0037] According to this embodiment, the pre-charge circuit 102 may include a switching device, such as a silicon-controlled rectifier (SCR) 104, and a current limiting resistor circuit 106. In other embodiments, such as Figure 1A As shown in the inserted portion of FIG. 1 , the pre-charge circuit 102 may include a contact switch 105 as a switching device instead of the SCR 104. In this embodiment, the current limiting resistor circuit 106 may include a polymer positive temperature coefficient (PPTC) component 108, which is arranged in series with the SCR 104. This pre-charge circuit may be suitable for replacing an existing pre-charge circuit contactor with a resistor. In particular, in the embodiment of the contact switch 105, a resistor will be required for the normal operation of the pre-charge circuit 102.

[0038] Under normal operation, after the pre-charge state, the pre-charge circuit 102 will be open, and the first main contactor 122 will close the HV positive contactor to drive the system or charge the battery 120. Since the capacitor 132 can be charged before the first main contactor 122 and the second main contactor 124 are closed, there is no high inrush current and the components of the circuit 102 can operate normally. In addition, during a fault condition, the current limiting resistor circuit 106 will limit the current to allow de-latching of the SCR 104, or safe opening of a switch (such as contactor 105).

[0039] Steering Figure 1B , which shows an electronic circuit 150 according to other embodiments of the present disclosure. The electronic circuit 150 can be arranged similarly to the electronic circuit 100, where like components are labeled the same. The difference with respect to the electronic circuit 100 is that the pre-charge circuit 152 includes a current limiting resistor circuit 156, which, in addition to the PPTC component 108, also includes a resistor 210 arranged in electrical series with the SCR 104 and the PPTC component 108. Figure 1A As in the embodiment of the present invention, the SCR 104 can be replaced by the contact switch 105 in other embodiments. The use of the PPTC component 108 allows the pre-charge circuit to pass the peak power in multiple cycles with an under-rated resistor. In particular, the advantage of this current limiting resistor circuit 156 is that the overall pre-charge circuit is simpler, smaller and more cost-effective. The use of the PPTC component 108 allows the pre-charge circuit to pass the peak power in multiple cycles (such as 10 cycles) of normal pre-charge, with a suitable interval between cycles, such as 2 seconds, as OC protection.

[0040] Steering Figure 1C , which shows an electronic circuit 180 according to other embodiments of the present disclosure. The electronic circuit 180 can be arranged similarly to the electronic circuit 100, where like components are labeled the same. The difference with respect to the electronic circuit 100 is that the pre-charge circuit 182 includes a current limiting resistor circuit 186, which, in addition to the PPTC component 108, also includes a negative temperature coefficient (NTC) component 184 arranged in electrical series with the SCR 104 and the PPTC component 108. Figure 1A As in the embodiment of the present invention, the SCR 104 may be replaced by a contact switch 105 in other embodiments.

[0041] Figure 2 An electronic circuit 200 according to an embodiment of the present disclosure is shown, in which case a circuit similar to Figure 1A The electronic circuit 200 includes a PPTC component (31 ohm untripped state resistance) and a resistor R arranged in electrical series with a voltage source (such as a battery). Regarding the operation of the electrical circuit 200, a switch S is included.

[0042] Under the first capacitor charging condition, the applied voltage V=400V DC, wherein the PTC resistance R=31Ω, the capacitor capacitance C=2980μf, and the charging energy Uc=238J.

[0043] The energy Uc stored in the bus capacitance is similar to the energy generated in the pre-charging system. Figure 2 The capacitor charging curve of the circuit is Figure 3A The experimental data shown in FIG. 1 include the charging current and the charge on the capacitor, both of which are shown as a function of time (in seconds). Figure 3B-3D Shows Figure 3A Details. Figures 3A-3D In the results, it is assumed that the temperature is 23°C. The average power on time is 0.30s and the off time is s. As shown in the figure, the electronic circuit 200 limits the inrush current when the contactor (switch S) is in the closed moment. In the current limiting mode, the current limiter is in the current limiting state but not in the protection state. Figure 3B-3D shown, and especially in Figure 3C In the example, the current decays to zero in about 0.1 seconds while the voltage remains at 400V.

[0044] Table I presents the temperature of the electronic circuit 200 according to different cycle numbers for operation under scenario 1.

[0045] Table I

[0046] cycle,# 1 2 3 5 10 11 cycles & power on > 20 seconds later Maximum temperature, C 30.8 34.5 41.8 46.2 67.9 ≥200

[0047] Figure 4A A reference circuit 400 is shown, while Figure 4B shows that under the second capacitor charging condition Figure 4A The reference circuit of Figure 1 calculates the capacitor charging for voltage and current over 10 charge cycles. In this example, Figure 4A The reference circuit 400 includes a 58 ohm resistor to allow a current of about 10 A applied at a voltage of 600 VDC. In this case, the total energy Uc for a full charge of the 2400 μF capacitor is 432 J. Figure 4C shows that under the second capacitor charging condition Figure 4A The reference circuit calculates the capacitor charging for voltage and current. By way of explanation, the energy Uc stored in the bus capacitance is similar to the energy generated in the pre-charging system. Figure 4B The capacitor charging curve shown in includes the charging current and the charge on the capacitor, which shows these two quantities as a function of time (in seconds). The total energy to fully charge the capacitor can be given by the following equation

[0048]

[0049] Among them U C is the energy stored in the capacitor, Q is the charge, V is the voltage, and C is the capacitance. In this example, the total energy Uc in the capacitor at one full charge is 432J.

[0050] Figure 5A Another electronic circuit according to an embodiment of the present disclosure is shown as electronic circuit 500. Electronic circuit 500 includes a PPTC component (0.14 ohm untripped state resistance) and a resistor R2 (20 ohms) arranged in series with a voltage source (such as a battery). A preload resistor R1 is also included, which has a resistance of 37 ohms to control the current of 10A to be applied to electronic circuit 500, so that the total resistance of electronic circuit 500 simulates the 58 ohm resistor of reference circuit 400. Figure 5B As shown above Figure 4A Under the non-tripping condition of the second capacitor charging condition discussed, Figure 5A Experimental results of pulse charging tests on electronic circuits. In particular, Figure 5B 25 charging cycles with power on and power off are shown in TABLE II. The temperature of the electronic circuit 500 according to different numbers of charging cycles is shown in Table II.

[0051] Table II

[0052] pulse 1 10 20 25 Current at 1s, A 10.50 9.36 8.80 10.30 PPTC maximum temperature, C 31.4 43.5 54.5 56.3

[0053] Figure 5C It is shown that in a protection mode triggered by an extended charging time, or / and an over-temperature or / and an over-current condition, an under-rated resistor can be protected. Figure 5A Experimental results on the behavior of electronic circuits.

[0054] Figure 6 A reference circuit 600 is shown, while Fig. 6A shows the third capacitor charging condition Figure 6 The reference circuit calculates the capacitor charge. Figure 6B shows the 10 charging cycles under the third capacitor charging condition according to Fig. 6A The reference circuit 600 calculates the capacitor charging for voltage and current. Under this charging condition, for Figure 6 The reference circuit of 800V DC is applied, where the resistance of resistor R is 67 ohms to allow 12A current, and the capacitance C of the capacitor is 2400μf. The total energy Uc for one complete charging cycle is 768J.

[0055] Fig. 7AAnother electronic circuit according to an embodiment of the present disclosure is shown as electronic circuit 700. Electronic circuit 900 includes a PPTC component (0.65 ohm untripped state resistance) and a resistor R2 (20 ohms) arranged in electrical series with a voltage source (such as a battery). A preload resistor R1 is also included, having a resistance of 46 ohms to control a current of 12A to be applied to electronic circuit 700, so that the total resistance of electronic circuit 700 simulates the 67 ohm resistor of reference circuit 600.

[0056] Figure 7B Shows the non-tripped condition Fig. 7A The simulation results of the pulse charging test of the electronic circuit 700 are shown in FIG. Figure 7B FIG. 5 shows multiple charging pulses with power on and power off, where the temperature across the PPTC component is 34.1°C.

[0057] Figure 7C shows the protection mode triggered by the extended charging time Fig. 7A 700. In this example, the PPTC switch temperature is 125°C, and the PPTC component has reached a temperature of 130.8°C, while the resistor R2 has been maintained at a temperature below 100°C, and specifically at a low temperature of 31.4°C.

[0058] Figure 8 800 according to an embodiment of the present disclosure. Fig. 8A shows the fourth capacitor charging condition Figure 8 The reference circuit 800 calculates the capacitor charge while Figure 8B The capacitor charging for voltage calculated by the fourth capacitor charging condition reference circuit 800 under ten charging cycles is shown. In addition, Figure 8C The capacitor charging versus current calculated according to the reference circuit 800 over ten charging cycles for a fourth capacitor charging condition is shown.

[0059] Under this capacitor charging condition, 400V DC is applied, where for Figure 8 For the reference circuit, the resistance of resistor R is 20 ohms to allow 20A current, and the capacitance C of the capacitor is 2400μf. The total energy Uc for a complete charging cycle is 768J.

[0060] Fig. 9AA further electronic circuit according to an embodiment of the present disclosure is shown, shown as electronic circuit 900. Electronic circuit 900 includes a PPTC component (0.126 ohm untripped state resistance) and an NTC component N (9.14 ohm resistance), which are arranged in electrical series with a voltage source (such as a battery). A preload resistor R1 is also included, having a resistance of 10 ohms to control a current of 20A to be applied to electronic circuit 900. In this way, the total resistance of electronic circuit 900 simulates the 20 ohm resistor of reference circuit 800.

[0061] Fig. 9B is a composite graph showing the characteristics of the electronic circuit 900 under a non-tripped condition during operation under a fourth capacitor charging condition, and Fig. 9C The electronic circuit 900 is shown in a protection mode triggered by an extended charging time. Fig. 9A A composite diagram of the characteristics of the electronic circuit 900. In particular, Fig. 9B Involving 10 charging cycles with 1s on and 120s off. In this example, the resistance of the PPTC component and the NTC component N will not change substantially after 10 cycles, as shown in Fig. 9B Note that the presence of the NTC component N can offset some of the current reduction from the PPTC component to avoid excessive current limiting in the capacitor charging state.

[0062] like Fig. 9C As shown, the current limiter will be in self-protection mode under fault conditions, such as when charging is longer than 5.2 seconds. Fig. 9C In the experiment, 400V DC was applied at 20A with 15s ON / 120s OFF for 10 cycles. Once again, no significant resistance change was seen in the PPTC and NTC components after 10 charging cycles. Fig. 9B It is particularly shown that when the duration of power-on is 1 second, the combination of PTC+NTC devices is in a non-tripped state. Fig. 9C It is shown that the PTC+NTC device is in protection mode when the power-on duration is 5 seconds.

[0063] Table III presents a summary of the circuit limiting components of this embodiment compared to components of known circuits.

[0064] Table III

[0065]

[0066] Although the foregoing examples specifically describe circuits using PPTC components, according to further embodiments, ceramic PTC devices (CPTC) devices may be used instead of PPTC components. Ceramic PTCs may be designed to trip in a manner similar to PPTC components, i.e., transition from a high conductivity state to a low conductivity state under overcurrent and / or overtemperature conditions.

[0067] Fig.10 An exemplary process flow 1000 is depicted. At box 1002, a battery circuit is provided. The battery circuit may include a first terminal line, a first main contactor, a second terminal line, and a second main contactor, wherein the first main contactor and the second main contactor are connected in series along the first terminal line and the second terminal line, respectively. The battery circuit may also include a precharge circuit, which is connected along a precharge path extending in parallel with the first main contactor. Therefore, the precharge circuit may include a component acting as a switch, such as a silicon controlled rectifier (SCR), or alternatively, a contact switch, and a positive temperature coefficient (PTC) component arranged in series with the switch. In various embodiments, the PTC component is a polymer positive temperature coefficient (PPTC) device. In other embodiments, the PTC component is a ceramic PTC component. In some embodiments, the precharge circuit may also include a resistor, which is arranged in series with the SCR (or contact switch) and the PTC component, or an NTC component, which is arranged in series with the SCR (or contact switch) and the PTC component.

[0068] At block 1004, the first main contactor and the second main contactor are maintained in an open position during a first state. During the first state, the battery coupled to the first terminal line and the second terminal line is thus disconnected from the external load.

[0069] At block 1006 , the second main contactor is placed in a closed position during a pre-charge state and current flows through the pre-charge circuit.

[0070] At block 1008 , the first main contactor is closed while maintaining the second main contactor in a closed position during the charging state.

[0071] Although the present embodiment has been disclosed with reference to certain embodiments, many modifications, variations and changes to the described embodiments are possible without departing from the field and scope of the present disclosure as defined by the appended claims. Therefore, the present embodiment is not limited to the described embodiments, and may have the full scope defined by the language of the following claims and their equivalents.

Claims

1. A pre-charging circuit, comprising: a switching device for controlling the voltage to be supplied to the battery; as well as a current limiting resistor circuit coupled to the switching device, wherein the current limiting resistor circuit comprises: A positive temperature coefficient (PTC) component is arranged in electrical series with the switching device.

2. The precharge circuit according to claim 1, wherein: The switching device and the current limiting resistor circuit are disposed along a pre-charge path that is arranged in electrical parallel with a terminal line for coupling to a battery terminal of the battery.

3. The precharge circuit according to claim 2, wherein: A first end of the pre-charging path is coupled on a first side of a main contactor arranged on the terminal line, and wherein a second end of the pre-charging path is coupled on a second side of the main contactor.

4. The precharge circuit of claim 1, further comprising a resistor electrically arranged in series with the switching device and the PTC component.

5. The precharge circuit according to claim 4, wherein: The PTC component is thermally coupled to the resistor.

6. The precharge circuit of claim 1, further comprising a negative temperature coefficient of resistance (NTC) component electrically arranged in series with the switching device and the PTC component.

7. The precharge circuit according to claim 1, wherein: The switching device is a silicon controlled rectifier (SCR), or a contact switch.

8. The precharge circuit according to claim 1, wherein: The current limiting resistor circuit is arranged to limit current, wherein the switching device is a silicon controlled rectifier (SCR), and wherein unlatching of the SCR occurs during a fault condition.

9. A battery circuit comprising: a first terminal wire for connecting an external component to a first terminal of the battery; a first main contactor connected in series along the first terminal line; as well as a pre-charging circuit connected between the first terminal and the external component along a pre-charging path extending in parallel with the first main contactor, the pre-charging circuit comprising: Switching devices; and a current limiting resistor circuit electrically coupled in series to the switching device, wherein the current limiting resistor circuit comprises: A positive temperature coefficient (PTC) component is arranged in electrical series with the switching device.

10. The battery circuit according to claim 9, wherein: A first end of the pre-charge path is coupled to a first side of the first main contactor, and wherein a second end of the pre-charge path is coupled to a second side of the main contactor.

11. The battery circuit of claim 9, further comprising a resistor arranged in electrical series with the switching device and the PTC assembly.

12. The battery circuit according to claim 11, wherein: The PTC component is thermally coupled to the resistor.

13. The battery circuit according to claim 9, wherein: The current limiting resistor circuit is arranged to limit current, wherein the switching device is a silicon controlled rectifier (SCR), and wherein unlatching of the SCR occurs during a fault condition.

14. A method for managing the flow of current in an electronic circuit, comprising: A battery circuit is provided, comprising: a first terminal wire for connecting an external component to a first terminal of the battery; a first main contactor connected in series along the first terminal line; a second terminal wire for connecting the external component to a second terminal of the battery; a second main contactor connected in series along the second terminal line; and a pre-charge circuit connected between the first terminal and the external component along a pre-charge path extending in parallel with the first main contactor; maintaining the first main contactor and the second main contactor in an open position during a first state; placing the second main contactor in a closed position and allowing current to flow through the pre-charge circuit during a pre-charge state; and closing the first main contactor while maintaining the second main contactor in the closed position during a charging state, Wherein, the pre-charging circuit comprises: Switching devices; and A current limiting resistor circuit includes a positive temperature coefficient (PTC) component arranged in electrical series with a switching device.

15. The method of claim 14, during the pre-charge state: Multiple charging pulses are generated in a cluster.

16. The method according to claim 15, wherein: The clusters comprise 5 to 25 charging pulses.

17. The method according to claim 15, wherein: A duration of one to five seconds occurs between the first pulse and the second pulse of the charging pulse.

18. The method of claim 15, further comprising a resistor arranged in electrical series with the switching device and the PTC assembly.

19. The method according to claim 18, wherein: During a fault condition, the PTC assembly enters a tripped state while the resistor is maintained at a temperature below 100°C.

20. The method of claim 15, further comprising a negative temperature coefficient of resistance (NTC) component arranged in electrical series with the switching device and the PTC component.

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