Open-phase current protection system and method for a motor controller

Abstract

The application provides a system and method for open-phase current protection of a motor controller, the system comprising a first phase current sensor and a second phase current sensor, and further comprising: a first phase resistor R u ; a second phase resistor R v ; a bias resistor R bias ; an operational amplifier comprising a plus input end, a minus input end and an output end, the first phase resistor R u , the second phase resistor R v and the bias resistor R bias being connected to the plus input end, and the output end being connected to the minus input end; the plus input end receiving and superimposing a first phase voltage U u generated by the first phase current sensor, a second phase voltage U v generated by the second phase current sensor and a bias voltage U bias generated by a bias voltage source to obtain an equivalent open-phase voltage U w ; the operational amplifier comparing the open-phase voltage U w with a threshold voltage, so that the output end determines whether to output an overcurrent fault signal according to the comparison result. By using the above technical scheme, the overcurrent protection of hardware for the open-phase current can be realized under the condition that only two current sensors exist.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of motor control, in particular to a phase-loss current protection system and method of motor controller. BACKGROUND

[0002] With the rapid development of new energy vehicles, many manufacturers have made a lot of research on the important electric control part, among which, in order to reduce the cost, two independent current sensors are often used to collect two-phase currents in the electric control, which makes the other phase without sensor hardware. When the current value of the other phase (phase-loss current) cannot be collected and overcurrent occurs, the phase-loss current cannot be protected by hardware, which increases the risk of electric control failure.

[0003] Therefore, a new phase-loss current protection system of motor controller is needed, which can indirectly obtain accurate phase-loss current without increasing additional hardware, so as to realize overcurrent protection when overcurrent occurs in phase-loss current. SUMMARY

[0004] In order to overcome the above technical defects, the purpose of the present application is to provide a phase-loss current protection system and method of motor controller, which can still realize hardware overcurrent protection for phase-loss current under the condition of only two current sensors.

[0005] The present application discloses a phase-loss current protection system of motor controller, which comprises a first-phase current sensor and a second-phase current sensor arranged on a three-phase circuit of the motor controller, and further comprises:

[0006] a first-phase resistor R u , one end of which is connected with the first-phase current sensor;

[0007] a second-phase resistor R v , one end of which is connected with the second-phase current sensor;

[0008] a bias resistor R bias , one end of which is connected with a bias voltage source;

[0009] an operational amplifier, which comprises an addition input end, a subtraction input end and an output end, the other end of the first-phase resistor R u , the other end of the second-phase resistor R v and the other end of the bias resistor R bias are connected to the addition input end, and the output end is connected to the subtraction input end;

[0010] an overcurrent comparison unit, which is connected to the output end of the operational amplifier;

[0011] The operational amplifier receives and superimposes the first phase voltage U generated by the first phase current sensor. u The second phase voltage U generated by the second phase current sensor v and subtract the bias voltage U generated by the bias voltage source bias With equivalent phase loss voltage U w ;

[0012] The operational amplifier converts the phase loss voltage U w The signal is sent to the overcurrent comparison unit, which then sends the phase loss voltage U. w The overcurrent comparison unit determines whether to output an overcurrent fault signal based on the comparison result by comparing the voltage with a threshold voltage.

[0013] Preferably, the phase loss current protection system further includes:

[0014] Resistor R2 has one end grounded and the other end connected to the addition input terminal;

[0015] A voltage source VCC is connected to an operational amplifier to generate a threshold voltage.

[0016] resistor R f One end is connected to the subtraction input terminal, and the other end is connected to the output terminal.

[0017] Preferably, the first phase resistance R u The second phase resistor R v Bias resistor R bias Resistor R2, Resistor R f All of them have the same resistance value.

[0018] Preferably, the input voltage received by the adder input terminal is the first phase resistance R. u The second phase resistor R v The sum of the bias resistor R bias The difference, of which

[0019] U u =ki u +U bias U v =ki v +U bias Where k is the internal resistance coefficient of the first phase current sensor and the second phase current sensor, i u Let i be the first phase current. v This is the second phase current;

[0020] Based on the fact that the sum of the three-phase currents of the motor controller is 0, U u +U v -U bias =k(-i w )+U biasThe equivalent open-phase current i is w The open-phase voltage U generated by the open-phase current i w .

[0021] The application further discloses a method for open-phase current protection of a motor controller, comprising the following steps:

[0022] An open-phase current protection circuit is configured based on the following configuration, the open-phase current protection circuit comprises a first-phase current sensor and a second-phase current sensor arranged on a three-phase circuit of the motor controller, and further comprises: a first-phase resistor R u connected at one end to the first-phase current sensor; a second-phase resistor R v connected at one end to the second-phase current sensor; a bias resistor R bias connected at one end to a bias voltage source; an operational amplifier comprising an addition input end, a subtraction input end and an output end, the other end of the first-phase resistor R u , the other end of the second-phase resistor R v and the bias resistor R bias are connected to the addition input end, the other end of the bias resistor R u is connected to the subtraction input end, and the output end is connected to the subtraction input end; and an overcurrent comparison unit connected to the output end of the operational amplifier.

[0023] The operational amplifier receives and superimposes a first-phase voltage U v generated by the first-phase current sensor and a second-phase voltage U bias generated by the second-phase current sensor and subtracts a bias voltage U w generated by the bias voltage source to generate an equivalent open-phase voltage U .

[0024] The operational amplifier sends the open-phase voltage U w to the overcurrent comparison unit, and the overcurrent comparison unit compares the open-phase voltage U w with a threshold voltage, so that the overcurrent comparison unit determines whether to output an overcurrent fault signal according to a comparison result.

[0025] Preferably, the open-phase current protection circuit further comprises:

[0026] a resistor R2 connected at one end to the ground and at the other end to the addition input end;

[0027] a voltage source VCC connected to the operational amplifier to generate the threshold voltage;

[0028] a resistor R f connected at one end to the subtraction input end and at the other end to the output end.

[0029] Preferably, the first-phase resistor R u and the second-phase resistor R v, bias resistor R bias , resistor R2, resistor R f The resistance of each of the resistors is the same.

[0030] Preferably, the operational amplifier receives and superimposes a first-phase voltage U u generated by the first-phase current sensor, a second-phase voltage U v generated by the second-phase current sensor, and subtracts a bias voltage U bias generated by the bias voltage source, to obtain an equivalent open-phase voltage U w The steps include:

[0031] The input voltage received by the summing input terminal is the sum of the first-phase resistance R u , the second-phase resistance R v , and the difference between the bias resistance R bias , wherein

[0032] U u = ki u + U bias , U v = ki v + U bias , wherein k is the internal resistance coefficient of the first-phase current sensor and the second-phase current sensor, i u is the first-phase current, and i v is the second-phase current.

[0033] Based on the three-phase current of the motor controller being 0, U u + U v - U bias = k (-i w ) + U bias , so as to obtain an equivalent open-phase current -i w , and the open-phase voltage U w generated by the open-phase current.

[0034] After the above technical solution is adopted, compared with the prior art, the following beneficial effects are obtained:

[0035] 1. Without increasing the hardware cost, it can be quickly and accurately determined whether the open-phase current is overcurrent and alarm protection is performed.

[0036] 2. The reliability of the motor controller is further increased. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The figure is a circuit topology design schematic diagram of the open-phase protection system in the preferred embodiment of the present application. DETAILED DESCRIPTION

[0038] The advantages of the present application are further described below in combination with the drawings and specific embodiments.

[0039] The exemplary embodiments will be described in detail herein with reference to the attached drawings. In the following description, like reference numerals refer to like elements throughout the description. The following exemplary embodiments are not representative of all embodiments consistent with the present disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0040] The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used in the present disclosure and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0041] It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It is to be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0042] In the description of the present application, it should be understood that the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are terms of convenience and are not intended to limit the orientation of the apparatus or element being described unless specifically so indicated.

[0043] In the description of the present application, unless otherwise specified and limited, it should be understood that the terms "mounting", "connection", "connecting" should be interpreted broadlyly, for example, it can be mechanical connection or electrical connection, it can be the communication between two elements, it can be direct connection or indirect connection through intermediate medium, and the specific meaning of the above terms can be understood by the person skilled in the art according to the specific circumstances.

[0044] In the following description, the suffixes used for elements such as "module", "part" or "unit" are used only for convenience of explanation of the present application, and they do not have specific meaning by themselves. Therefore, "module" and "part" can be used interchangeably.

[0045] See Figure 1 This diagram illustrates a topology design of a phase loss current protection system for a motor controller according to a preferred embodiment of the present invention. In this embodiment, a first-phase current sensor and a second-phase circuit sensor are included, which can be respectively mounted on IGBT chips on two phases of the three-phase circuit of the motor controller to collect the current of each phase and generate two-phase voltage signals. In this embodiment, since no current sensor is mounted on the third phase, the phase loss current protection system further includes a first-phase resistor R. u One end is connected to the first phase current sensor; the second phase resistor R v One end is connected to the second phase current sensor; bias resistor R bias One end is connected to a bias voltage source, then the voltage signal generated by the first phase current sensor passes through the first phase resistor R. u Passed to the first phase resistor R u At the other end, the voltage signal generated by the second-phase current sensor passes through the second-phase resistor R. v Passed to the second phase resistor R v At the other end, the bias voltage generated by the bias voltage source will pass through the bias resistor R. bias Passed to bias resistor R bias On the other end. In other words, the current and voltage of the missing phase are indirectly calculated using the voltage signals collected by the first-phase current sensor and the second-phase current sensor.

[0046] Meanwhile, the phase loss current protection system also includes an operational amplifier, which has an addition input terminal, a subtraction input terminal, and an output terminal, and the first phase resistor R u The other end, the second phase resistor R v The other end is connected in parallel to the addition input terminal, with bias resistor R. bias The other end is connected in parallel to the subtraction input terminal, so that the voltage received at the addition input terminal is the first phase voltage U generated by the first phase current sensor. u The second phase voltage U generated by the second phase current sensor v The sum of these and the bias voltage U generated by the bias voltage source bias The difference is used to simulate the phase loss voltage U of the phase without a current sensor by addition. w The subtraction input is connected to the output. In other words, the operational amplifier is then connected to an overcurrent comparator unit, which converts the received two voltage signals, i.e., the equivalent phase loss voltage U, into a single signal. w After being sent to the overcurrent comparator unit, the phase loss voltage U is processed by the overcurrent comparator unit. w Compared with the threshold voltage, when the phase loss voltage U w When the voltage exceeds the threshold voltage, the overcurrent comparator unit outputs an overcurrent fault signal; when the phase loss voltage U wWhen the voltage is less than the threshold voltage, the output terminal will not output an overcurrent fault signal, indicating that the current phase loss current has not exceeded the threshold and is in normal operating condition of the electronic control.

[0047] With the above configuration, it is possible to accurately and quickly determine whether the third-phase current is overcurrent without the need for additional current sensors.

[0048] Furthermore, the phase loss current protection system also includes: resistor R2, one end grounded, the other end connected to the adder input; voltage source VCC, connected to the operational amplifier; resistor R f One end is connected to the subtraction input terminal, and the other end is connected to the output terminal.

[0049] Furthermore, the first phase resistance R u The second phase resistor R v Bias resistor R bias Resistor R2, Resistor R f The resistance values ​​are all the same, so the adder input terminal responds to the first phase voltage U. u The second phase voltage U generated by the second phase current sensor v and the bias voltage U generated by the bias voltage source bias When superimposed, there is no weighting effect.

[0050] In another embodiment, the input voltage received at the adder input terminal is the first phase resistor R. u The second phase resistor R v Bias resistor R bias The sum of, where U u =ki u +U bias U v =ki v +U bias Where k is the internal resistance coefficient of the first phase current sensor and the second phase current sensor, i u Let i be the first phase current. v This is the second phase current; based on the fact that the sum of the three-phase currents of the motor controller is 0, U u +U v =ki u +ki v +2·U bias Then U u +U v =-ki w +2·U bias Furthermore, U u +U v -U bias =k(-i w )+U bias Equivalent to a phase loss current -i w The phase loss voltage U generated beloww Understandably, because i w The current is alternating current, so i w The maximum and minimum values ​​and -i w The maximum and minimum values ​​are the same, therefore, when -i w When calculating the phase loss voltage using i as a reference, it is equivalent to using i as the reference. w The phase loss voltage is calculated based on this.

[0051] This invention also discloses a phase loss current protection method for a motor controller, comprising the following steps: a phase loss current protection circuit is configured as follows, the phase loss current protection circuit including a first phase current sensor and a second phase current sensor disposed on the three-phase circuit of the motor controller, and further comprising: a first phase resistor R. u One end is connected to the first phase current sensor; the second phase resistor R v One end is connected to the second phase current sensor; bias resistor R bias One end is connected to a bias voltage source; the operational amplifier includes an adder input, a subtractor input, and an output; the first phase resistor R... u The other end, the second phase resistor R v The other end is connected in parallel to the addition input terminal, with bias resistor R. bias The other end is connected to the subtraction input, and the output is connected to the subtraction input; the overcurrent comparator is connected to the output of the operational amplifier; the operational amplifier receives and superimposes the first phase voltage U generated by the first phase current sensor. u The second phase voltage U generated by the second phase current sensor v and subtract the bias voltage U generated by the bias voltage source bias With equivalent phase loss voltage U w The operational amplifier will convert the phase loss voltage U w The signal is sent to the overcurrent comparator unit, which will then input the phase loss voltage U. w The overcurrent comparison unit determines whether to output an overcurrent fault signal based on the comparison result by comparing the voltage with the threshold voltage.

[0052] Preferably, the phase loss current protection circuit further includes: a resistor R2, one end of which is grounded and the other end is connected to the addition input terminal;

[0053] A voltage source VCC is connected to an operational amplifier to generate a threshold voltage; resistor R f One end is connected to the subtraction input terminal, and the other end is connected to the output terminal.

[0054] Preferably, the first phase resistance R u The second phase resistor R v Bias resistor R bias Resistor R2, Resistor R f All of them have the same resistance value.

[0055] Preferably, the operational amplifier receives and superimposes the first phase voltage U u generated by the first phase current sensor, the second phase voltage U v generated by the second phase current sensor, and subtracts the bias voltage U bias generated by the bias voltage source, to generate an equivalent open-phase voltage U w The step includes that the input voltage received by the summing input terminal is the sum of the first phase resistance R u and the second phase resistance R v and the difference of the bias resistance R bias , wherein U u =k i u +U bias , U v =k i v +U bias , wherein k is the internal resistance coefficient of the first phase current sensor and the second phase current sensor, i u is the first phase current, and i v is the second phase current; based on the three-phase current of the motor controller being 0, so that U u +U v -U bias =k (-i w )+U bias to generate an open-phase voltage U w generated by the equivalent open-phase current -i w .

[0056] It should be noted that the embodiments of the present application have better implementation, and do not limit the present application in any form, and any skilled person in the art can change or modify the equivalent effective embodiments by using the above disclosed technical content, as long as it does not deviate from the technical solution of the present application, and any modification or equivalent change and modification of the above embodiments according to the technical essence of the present application still belongs to the scope of the technical solution of the present application.

Claims

1. A phase loss current protection system for a motor controller, comprising a first phase current sensor and a second phase current sensor disposed on the three-phase circuit of the motor controller, characterized in that, The phase loss current protection system also includes: First phase resistor R u One end is connected to the first phase current sensor; Second phase resistor R v One end is connected to the second phase current sensor; Bias resistor R bias One end is connected to a bias voltage source; An operational amplifier, including an adder input, a subtractor input, and an output, wherein the first phase resistor R u The other end, the second phase resistor R v The other end is connected in parallel to the addition input terminal, with bias resistor R. bias The other end is connected to the subtraction input terminal, and the output terminal is connected to the subtraction input terminal; An overcurrent comparator unit is connected to the output terminal of the operational amplifier; The operational amplifier receives and superimposes the first phase voltage U generated by the first phase current sensor. u The second phase voltage U generated by the second phase current sensor v and subtract the bias voltage U generated by the bias voltage source bias With equivalent phase loss voltage U w ; The operational amplifier converts the phase loss voltage U w The signal is sent to the overcurrent comparison unit, which then sends the phase loss voltage U. w The overcurrent comparison unit compares the voltage with a threshold voltage to determine whether to output an overcurrent fault signal based on the comparison result. When the phase loss voltage U... w When the voltage exceeds the threshold voltage, the overcurrent comparator unit outputs an overcurrent fault signal; when the phase loss voltage U w When the voltage is less than the threshold voltage, the output terminal does not output an overcurrent fault signal; The input voltage received at the adder input terminal is the first phase resistance R. u The second phase resistor R v The sum of the bias resistor R bias The sum of, among which , Where k is the internal resistance coefficient of the first phase current sensor and the second phase current sensor. This is the first phase current. This is the second phase current; Based on the fact that the sum of the three-phase currents of the motor controller is 0, and The current is alternating current. maximum and minimum values The maximum and minimum values ​​are the same, when... When calculating the phase loss voltage using this as a reference, it is equivalent to using... Calculate the phase loss voltage based on the reference, so that Equivalent to phase loss current The phase loss voltage U generated below w .

2. The phase loss current protection system as described in claim 1, characterized in that, The phase loss current protection system also includes: Resistor R2 has one end grounded and the other end connected to the addition input terminal; The voltage source VCC is connected to the operational amplifier; resistor R f One end is connected to the subtraction input terminal, and the other end is connected to the output terminal.

3. The phase loss current protection system as described in claim 2, characterized in that, First phase resistor R u The second phase resistor R v Bias resistor R bias Resistor R2, Resistor R f All of them have the same resistance value.

4. A method for protecting a motor controller from phase loss current, characterized in that, Includes the following steps: A phase loss current protection circuit is configured as follows. The phase loss current protection circuit includes a first phase current sensor and a second phase current sensor installed on the three-phase circuit of the motor controller, and also includes: a first phase resistor R. u One end is connected to the first phase current sensor; Second phase resistor R v One end is connected to the second phase current sensor; bias resistor R bias One end is connected to a bias voltage source; the operational amplifier includes an adder input, a subtractor input, and an output; the first phase resistor R u The other end, the second phase resistor R v The other end is connected in parallel to the addition input terminal, with bias resistor R. bias The other end is connected to the subtraction input terminal, and the output terminal is connected to the subtraction input terminal; the overcurrent comparator unit is connected to the output terminal of the operational amplifier; The operational amplifier receives and superimposes the first phase voltage U generated by the first phase current sensor. u The second phase voltage U generated by the second phase current sensor v and subtract the bias voltage U generated by the bias voltage source bias With equivalent phase loss voltage U w ; The operational amplifier converts the phase loss voltage U w The signal is sent to the overcurrent comparison unit, which then sends the phase loss voltage U. w The overcurrent comparison unit compares the voltage with a threshold voltage to determine whether to output an overcurrent fault signal based on the comparison result. When the phase loss voltage U... w When the voltage exceeds the threshold voltage, the overcurrent comparator unit outputs an overcurrent fault signal; when the phase loss voltage U w When the voltage is less than the threshold voltage, the output terminal does not output an overcurrent fault signal; The input voltage received at the adder input terminal is the first phase resistance R. u The second phase resistor R v The sum of the bias resistor R bias The sum of, among which , Where k is the internal resistance coefficient of the first phase current sensor and the second phase current sensor. This is the first phase current. This is the second phase current; Based on the fact that the sum of the three-phase currents of the motor controller is 0, and The current is alternating current. maximum and minimum values The maximum and minimum values ​​are the same, when... When calculating the phase loss voltage using this as a reference, it is equivalent to using... Calculate the phase loss voltage based on the reference, so that Equivalent to phase loss current The phase loss voltage U generated below w .

5. The phase loss current protection method as described in claim 4, characterized in that, The phase loss current protection circuit also includes: Resistor R2 has one end grounded and the other end connected to the addition input terminal; A voltage source VCC is connected to the operational amplifier to generate the threshold voltage; resistor R f One end is connected to the subtraction input terminal, and the other end is connected to the output terminal.

6. The phase loss current protection method as described in claim 5, characterized in that, First phase resistor R u The second phase resistor R v Bias resistor R bias Resistor R2, Resistor R f All of them have the same resistance value.

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