TWI705653B - Device and method for determining dc current - Google Patents

Abstract

A device for determining a DC current includes a current detecting circuit and a controlling device. The current detecting circuit is configured to detect and feeds back three phase-current signal values. The controlling device is configured to generate three phase-voltage control signal values according to the three phase-current signal values and a set of command values. The controlling device performs a process of DC current determination according to the three phase-current signal values and the three phase-voltage control signal values. The process of DC current determination includes determining the three phase-voltage control signal values, determining a plurality of component DC currents according to a result of the determination regarding the three phase-voltage control signal values and the three phase-current signal values, and determining a DC link current value inputted into the controlling device according to the plurality of component DC currents.

Description

Direct current estimation device and method

The present invention relates to a DC current estimation device and method, in particular to a DC link current estimation device and method for estimating a motor drive control device.

Generally speaking, in order to avoid damage to the motor drive control system due to abnormal input DC link current, it is necessary to monitor the state of the DC link current. Monitoring the status of the DC link current can provide diagnostic and protection functions on the DC side of the drive control system, and (for example, in the power generation mode) control the output of the DC link current to stabilize the system's power generation.

In order to monitor the state of the DC link current, the traditional method is to install a current sensor on the high voltage DC side of the motor drive control system. This current sensor is used to capture the state of the DC link current input to the drive control system. However, this approach not only requires additional sensing elements, but also increases the circuit volume and cost.

In view of this, the present invention proposes a DC current estimation device and method, which mainly calculates the three-phase current and three-phase voltage control signals generated by the motor's drive control device to estimate the DC link current value to solve traditional needs The additional installation of DC sensors on the high-voltage DC side and the resulting increase in circuit volume.

According to an embodiment of the present invention, a DC current estimation device is provided, which is suitable for a motor. The DC current estimation device includes a current detection circuit and a driving control device. The current detection circuit is electrically connected to the motor and used to detect and feedback the three-phase current signal value of the motor. The drive control device is electrically connected to the current detection circuit and the motor. The drive control device is used to generate a three-phase voltage control signal value according to the three-phase current signal value and a set of command values, wherein each phase voltage control signal value corresponds to the One of the phase current signal values. The driving control device executes a DC current estimation procedure according to the feedback value of the three-phase current signal and the value of the three-phase voltage control signal. The DC current estimation procedure includes: judging the magnitude of the phase voltage control signal values, and determining the DC current values of a plurality of components according to the judgment result and the three-phase current signal value, and estimating according to the DC current values of the components Input the DC link current value of the drive control device.

According to an embodiment of the present invention, a DC current estimation method is provided, which includes the following steps: a current detection circuit detects and feeds back a three-phase current signal value of a motor; and a driving control device is used to depend on the three-phase current signal value A three-phase voltage control signal value is generated with a set of command values; and the drive control device executes a DC current estimation procedure according to the feedback of the three-phase current signal value and the three-phase voltage control signal value. Wherein, the DC current estimation procedure includes determining the magnitude of the three-phase voltage control signal value, and determining the DC current values of a plurality of components according to the determination result and the value of the three-phase current signal, and according to the DC current values of the components Estimate the DC link current value input to the drive control device.

In summary, in the DC current estimation device and method proposed in the present invention, the three-phase current signal value of the motor is first fed back through the original current sensor, and the three-phase current signal value and the preset Set the command value to generate a three-phase voltage control signal value, and then further estimate the DC link current value based on the three-phase current signal value and the three-phase voltage control signal value. In this way, under the architecture of the original motor drive control system, it is possible to achieve the purpose of monitoring the current value of the DC link without installing an additional DC sensor on the high-voltage DC side of the system and without occupying circuit space.

The above description of the content of the disclosure and the description of the following embodiments are used to demonstrate and explain the spirit and principle of the present invention, and to provide a further explanation of the patent application scope of the present invention.

The detailed features and advantages of the present invention are described in detail in the following embodiments, and the content is sufficient to enable anyone familiar with the relevant art to understand the technical content of the present invention and implement it accordingly, and according to the content disclosed in this specification, the scope of patent application and the drawings Anyone who is familiar with the relevant art can easily understand the related purpose and advantages of the present invention. The following examples further illustrate the viewpoints of the present invention in detail, but do not limit the scope of the present invention by any viewpoint.

Please refer to FIG. 1A. FIG. 1A is a structural diagram of a motor drive control operation system according to an embodiment of the present invention. As shown in FIG. 1A, the motor drive control operation system 1 is connected to the motor 2 and the motor drive control operation system 1 includes a drive control device 10, a current detection circuit 11 and a power supply source 12. In this embodiment, the motor 2 may be, for example, a three-phase motor for a vehicle, but it is not limited to this. For the convenience of description, the motor 2 will be described below as a three-phase motor. In this embodiment, the drive control device 10 and the current detection circuit 11 of the motor drive control operation system 1 can form a DC current estimation device.

In the motor drive control operation system 1, the power supply source 12 is composed of a power source 121 and a capacitor 122 to provide a power. The power source 121 and the capacitor 122 are connected in parallel, and the power includes a DC link current I input to the drive control device 10 _DC . A plurality of current detection circuit 11 comprises a current sensor S1 ~ S3, the motor 2 are provided in three phases for detecting three-phase input to the motor current I _A 2 is, I _B, I _C and feedback Three phase current signal values i _a , i _b , and i _c . The drive control device 10 includes a control circuit 101 and a switch drive circuit 102 composed of a plurality of transistor switches T1 to T6 in pairs, wherein the transistor switches T1 and T4 are connected in series to form phase A; the transistor switches T2 and T5 are connected in series to form phase B; Transistor switches T3 and T6 are connected in series to form phase C.

In actual practice, the control circuit 101 drive control device 10 according to the signal value of the three phase currents i _a, i _b, i _c and a set of command value _I d_ref, I q_refc. Among them, in this embodiment, for the convenience of the subsequent description, it is assumed that the three phase current signal values i _a , i _b , and i _c are the first phase current signal value i _a , the second phase current signal value i _b and the first phase current signal value i _{b, respectively.} signal phase current value i _c, and the three phase voltage control signal value V _a, V _b, V _c are the first phase voltage control signal value V _a, the second phase voltage control signal value V _b and the third phase voltage Control signal value V _c .

Specifically, the control circuit 101 may first obtain the position information PS of the motor 2. The position information is the rotation information of the motor 2. That is, the control circuit 101 can detect the rotation state of the rotor relative to the stator when the motor 2 is operating by providing a position sensor 13 as shown in FIG. The rotation information is used as the position information PS, but the present invention is not limited to the position sensor 13, and the control circuit 101 may not obtain the position information PS through the position sensor 13, that is, the position information PS is not necessary. Please further refer to FIG. 1B, which is an internal functional block diagram of the control circuit shown in the embodiment of FIG. 1A according to the present invention. As shown in the figure, the control circuit 101 includes a first coordinate conversion unit 1011, a current error estimation unit 1012, a current control unit 1013, a second coordinate conversion unit 1014, and a signal conversion unit 1015. When the control circuit 101 receives the feedback signal of the phase current value i _a, i _b, when i _c, a first coordinate conversion unit 1011 of the three-phase current signal value i _a, i _b, i _c to convert variable transmission Clark I _α and I _{β are} further converted into variables I _d and I _q by Park according to the variables I _α , I _β and the position information PS and output to the current error estimation unit 1012. Next, the current error estimation unit 1012 calculates an error value according to the variables I _d and I _q and the set of command values I _{d_ref} and I _{q_ref} , wherein the error values are the variables I _d and I _q and their respective command values I _{d_ref} , The current error value obtained by comparing I _{q_ref} . The current control unit 1013 calculates the voltage vectors V _d and V _q according to the current error value, and converts them into variables V _α and V _β through the second coordinate conversion unit 1014 (inverse Park conversion), and the signal conversion unit 1015 according to the variable V _α and V _β calculate the target three-phase voltage value to be applied to the motor by means of, for example, space vector modulation (SVPWM), and generate a control signal GS according to the target three-phase voltage value, and the control signal GS includes a duty cycle value , mainly for controlling the plurality of transistor switches T1 ~ T6, thereby generating the three phase voltage control signal value V _a group of intermediate nodes each transistor switch, V _b, V _c. The three-phase voltage control signal V _a, V _b, V _c respectively correspond to the three-phase current signal value _{i a, i b, i c} . In practice, the control circuit 101 can be performed according to the control signal switching transistor T1 ~ T6 is turned on / off, so that the drive control device 10 generates three phase voltage control signal value _{V a, V b, V c} , wherein The control signal includes a pulse width modulated variable (PWM) for controlling the transistor switches T1~T6 in the switch drive circuit 102 to complete a motor current loop control.

In this embodiment, the control circuit 101 of the drive control device 10 uses the three phase current signal values i _a , i _b , and i _{c fed back} and the generated three phase voltage control signal values V _a , V _b , V _c executes the DC current estimation procedure. In practice, the internal storage unit (not shown in the figure) of the control circuit 101 stores an application program including an algorithm. The control circuit 101 executes the DC current estimation procedure by running the algorithm of the application program. The algorithm content includes the following formula (1) to formula (6).

公式（1）

Formula 1)

In the formula (1) which, comparing the first three phase voltage control signal value V _a, V _b, V _c of the size, if V _a V _c> V _b and V _a>, and when V _b> V _c case Below, the first term in the brackets is true, but the second term is not true. The positive component DC current value Idc _ia+ of the first phase (a-phase) is i _a *(V _a -V _b )/2, that is, the first and second The difference of the phase (a, b) voltage control signals is multiplied by the first phase (a phase) current signal value i _a , and then divided by 2. When V _b >V _c , the first term in the brackets does not hold, and the second term holds. The positive component DC current value Idc _ia+ of the first phase (phase a) is i _a *(V _a -V _c )/2, which is also That is, the difference between the voltage control signal values of the first and second phases (a and c) is multiplied by the current signal value i _{a of the} first phase (a), and then divided by 2.

公式（2）

Formula (2)

In the formula (2) which, comparing the first three phase voltage control signal value V _a, V _b, V _c of the size, if V _a V _c> V _b and V _a>, and when V _b> V _c case Below, the first term in the brackets is true, but the second term is not true. The negative component DC current value Idc _ia+ of the first phase (a-phase) is i _a *(V _a -V _b )/2, that is, the first and second Multiply the difference between the phase (a, b) voltage control signal values by the first phase (a phase) current signal value i _a , and divide by 2. When V _b >V _c , the first term in the brackets does not hold, and the second term holds. The negative component DC current value of the first phase (a phase) Idc _ia- is i _a *(V _a -V _c )/2, That is, the difference between the voltage control signal values of the first and third phases (phase a and c) is multiplied by the current signal value i _{a of the} first phase (phase a), and then divided by 2.

公式（3）

Formula (3)

In the formula (3) which, comparing the first three phase voltage control signal value V _a, V _b, V _c of the size, if V _a V _c> V _b and V _b>, and when the case where V _a> V _c of Below, the first term in the brackets is true, but the second term is not true. The second phase (b-phase) positive component DC current value Idc _ib+ is i _b *(V _b -V _a )/2, that is, the second and the first Multiply the difference between the phase (b, a) voltage control signal values by the second phase (b phase) current signal value i _b , and divide by 2. When V _a > V _c , the first term in the brackets is not valid, and the second term is valid, and the positive component DC current value Idc _ib+ of the second phase (phase b) is i _b *(V _b -V _c )/2, also That is, the difference between the voltage control signal values of the second and third phases (phase b and c) is multiplied by the current signal value i _{b of the} second phase (phase b), and then divided by 2.

公式（4）

Formula (4)

In the formula (4) which, comparing the first three phase voltage control signal value V _a, V _b, V _c size, if V _a V _c> V _b and V _b>, and when the case where V _a> V _c of Below, the first term in the brackets is true, but the second term is not true. The second phase (b-phase) negative component DC current value Idc _ib- is i _b *(V _b -V _a )/2, that is, the second and the first The difference between the voltage control signal values of one phase (phase b and a) is multiplied by the current signal value i _{b of the} second phase (phase b), and then divided by 2. When V _c >V _a , the first term in the brackets is not true, and the second term is true, the second phase (phase b) negative component DC current value Idc _ib- is i _b *(V _b -V _c )/2, That is, the difference between the voltage control signal values of the second and third phases (phase b and c) is multiplied by the current signal value i _{b of the} second phase (phase b), and then divided by 2.

公式（5）

Formula (5)

In the formula (5) among the three-phase voltage to the comparison control signal value V _a, V _b, V _c size, if V _a V _c> V _c and V _b>, and when the case where V _a> V _b of Below, the first term in the brackets is true, but the second term is not true. The third phase (c-phase) positive component DC current value Idc _ic+ is i _c *(V _c -V _a )/2, that is, the third and the first Multiply the difference between phase (c, a) voltage control signal values by the third phase (phase c) current signal value i _c , and divide by 2. When V _a > V _b , the first term in the brackets is not valid, and the second term is valid, and the positive component DC current value of the third phase (c-phase) Idc _ic+ is i _c *(V _c -V _b )/2, also i.e., the third and the second phase (c, b-phase two) differential voltage control signal value multiplied by a third phase (c-phase) current signal value i _c, divided by two.

公式（6）

Formula (6)

In the formula (6) which, comparing the first three phase voltage control signal value V _a, V _b, V _c size, if V _a V _c> V _c and V _b>, and when the case where V _a> V _b of Below, the first item in the brackets is established, but the second item is not established. The negative component DC current value of the third phase (c-phase) Idc _ic- is i _c *(V _c -V _a )/2, that is, the third and the first Multiply the difference between the voltage control signal values of one phase (phase c and a) by the current signal value i _{c of the} third phase (phase c) and divide by 2. When V _a > V _b , the first term in the brackets does not hold, and the second term holds. The negative component DC current value Idc _ic- of the third phase (phase c) is i _c *(V _c -V _b )/2, That is, the difference between the voltage control signal values of the third and second phases (phase c and b) is multiplied by the current signal value i _{c of the} third phase (phase c), and then divided by 2.

分別代表回授的三個相電流訊號值i _a、i _b、i _c，

分別代表三個相電壓控制訊號值V _a、V _b、V _c可由系統偵測或量測獲得，而

分別代表各相的正/負分量直流電流值。其中，通常在實際運作上，回授的三相電流訊號值

會先經由系統進行標么化過程以進行上述的公式運算，因此當運算完成後的電流訊號值會再與基準值相乘以回推實際的直流電流值。 among them,

Respectively represent the three phase current signal values i _a , i _b , and i _{c of the} feedback,

They represent the three phase voltage control signal value V _a, V _b, V _c detection or measurement system may be obtained, and

Respectively represent the positive/negative component DC current value of each phase. Among them, usually in actual operation, the feedback three-phase current signal value

The standardization process will be performed by the system to perform the above formula calculations, so when the calculation is completed, the current signal value will be multiplied by the reference value to push back the actual DC current value.

與比較式

來說，如果三相電壓控制訊號值的大小關係為

，則比較式

成立，因此數值為1，而比較式

不成立，因此數值為0。 More specifically, the value of the comparison formula in each formula is 1 when it is established, and the value is 0 when it is not. For example, taking the comparison formula of formula (1)

And comparative

In other words, if the value of the three-phase voltage control signal is related to

, Then the comparative formula

Is true, so the value is 1, and the comparison formula

Not true, so the value is 0.

舉例說明，如果比較式(

)且(

)均成立時，則兩比較式的乘積

的值即為1。反過來說，如果比較式(

)與(

)任一個或兩者均不成立時，則兩比較式的乘積

的值即為0。其餘公式亦同，在此不予贅述。 Similarly, taking the product of the two comparisons of formula (1)

For example, if the comparison formula (

) And (

) Are both true, then the product of the two comparisons

The value of is 1. Conversely, if the comparison formula (

)versus(

) When either or both are not true, then the product of the two comparisons

The value of is 0. The other formulas are the same, so I won't repeat them here.

。以下將參照公式（1）至公式（6）詳述直流電流估測程序的細部內容。 As mentioned above, the calculation result of each of the above formulas represents a component DC current value. The estimated DC link current value I _{DC is} the sum of the DC current values of each component, that is, the DC link current value

. The following will refer to formula (1) to formula (6) to detail the details of the DC current estimation procedure.

The DC current estimation program comprising: a control circuit 101 determines three phase voltage control signal value V _a, V _b, V _c size, and according to a determination result and controls the three phase currents i _a signal value circuit 101, I _b and i _c to determine the DC current values of multiple components. Finally, the control circuit 101 then estimates the DC link current value I _o input to the drive control device 10 according to the DC current values of these components.

In detail, the control circuit 101 first judges the magnitude relationship of the three phase voltage control signal values Va, V _b , and V _c , and calculates them with the conditional expressions of each formula, and compares them with the three phase current signal values i _a , i _b and i _{c are} operated together. In practice, the control circuit 101 in accordance with the three-phase feedback current signal of each value i _a, i _b, i _c, and three-phase current signal according to the value i _a, i _b, i _c, and the control command value output signal The three phase voltage control signal values V _a , V _b , and V _c generated by the control transistor switches T1~T6 are brought into each formula to perform the product operation of the two comparison formulas. There is only one of the two comparison formulas in the two formulas. The product will be established (that is, the value is 1) and the actual value can be calculated as the first and second component DC current values, while the product of the two comparison formulas of the other four formulas will not be established (that is, the value is 0), so The component DC current values calculated by the other four formulas are all 0. In short, the magnitude relationship of any of the phase voltage control signal values V _a , V _b , and V _c will activate two of the six formulas in the control circuit 101, and obtain the component DC generated by the two formulas Current value.

，其中所述的相電壓控制訊號值可以例如是以百分比（0~100%）或標么值的形式表示。在這樣的情況下，僅有公式（1）與公式（6）的兩比較式的乘積

與

的值為1，其餘的公式（2）至公式（5）的兩比較式之乘積的值為0。亦即，除了第一相正分量直流電流值

與第三相負分量直流電流值

之外，其餘的分量直流電流值均為0。所述的第一相正分量直流電流值

與第三相負分量直流電流值

分別作為第一與第二分量直流電流值。接著，控制電路101將所述的第一與第二分量直流電流值進行加總以估算出輸入驅控裝置10的直流鏈電流值I _DC。 For example, suppose that the control circuit 101 determines the magnitude relationship of the three-phase voltage control signal value as

, Wherein the phase voltage control signal value can be expressed in the form of percentage (0~100%) or per unit value, for example. In this case, only the product of the two comparison formulas of formula (1) and formula (6)

versus

The value of is 1, and the product of the two comparison formulas in the remaining formulas (2) to (5) is 0. That is, in addition to the positive component DC current value of the first phase

And the third phase negative component DC current value

Except for the other components, the DC current values are all zero. The first phase positive component DC current value

And the third phase negative component DC current value

As the first and second component DC current values respectively. Next, the control circuit 101 sums the first and second component DC current values to estimate the DC link current value I _DC input to the drive control device 10.

Please further refer to FIG. 2. FIG. 2 is a method flowchart of a DC current estimation method according to an embodiment of the present invention. This method is applicable to the system architectures of FIGS. 1A and 1B. As shown in FIG. 2, in step S1, the current detection circuit 11 detects and feedbacks the three-phase current signal values i _a , i _b , and i _{c of the} motor 2. In step S2, the control device 10 is used to drive the three-phase current signal according to the value i _a, i _b, i _c and a set of command value _I d_ref, I q_ref GS outputs a control signal for controlling the plurality of transistor switches T1 ~ T6, according to the three transistor switches (T1, T4), (T2 , T5) and (T3, T6) of the intermediate node corresponding to the three-phase voltage to generate the control signal value _{V a, V b, V c} , which Relevant details have been described in the foregoing paragraphs, and will not be repeated here. Next, in step S3, to the drive control device 10 according to the plurality of phase current signal value of the feedback of i _a, i _b, i _c, and the plurality of the phase voltage control signal value V _a, V _b, V _c perform a DC current Estimate procedure. Please further refer to FIG. 3, which is a flowchart of the DC current estimation procedure in step S3 depicted in the embodiment of FIG. 2 of the present invention. 3, in step S10, it is determined that the three-phase voltage control signal value V _a, V _b, V _c of size. In step S11, based on the determination result and the three-phase current signal value i _a, i _b, i _c determining a plurality of direct current component value. In step S12, the DC link current value I _DC input to the drive control device 10 is estimated based on the component DC current values.

In one embodiment, the control circuit 101 shown in the foregoing steps S10 ~ S12 determines three phase voltage control signal value V _a, the size V _b, V _c, and the control circuit 101 according to a determination result, and three-phase current signal i _a, i _b, the current value i _c determines the plurality of components of the DC current value, and the control circuit 101 estimates the DC link current input actuation means 10 the value of I _o comprising the step S100 to step S120 based on the plurality of component DC current value, As shown in FIG. 4, FIG. 4 is a detailed flowchart of the DC current estimation program according to an embodiment of the present invention.

In step S100, the control circuit 101 determines three phase voltage control signal value V _a, V _b, V _c is the maximum value of the phase voltage control signal and the minimum value of the phase voltage control signal. In one embodiment, the step S100 determines the maximum phase voltage control signal value and the minimum phase voltage control signal value among the three-phase voltage control signals, and the middle phase voltage control signal value. For example, suppose the control circuit 101 compares the magnitude relationship of the three-phase voltage control signal values, and the comparison result is V _a > V _b > V _c , so V _a is defined as the maximum phase voltage control signal value, and V _c is the minimum phase voltage Control signal value, and V _b is the intermediate phase voltage control signal value. According to the above definition rule, if the comparison result is _{V b> V a> V c} , defines V _b is the maximum phase voltage control signal value, V _c is the minimum phase voltage control signal value, and V _a phase voltage controlled intermediate Signal value. The rest of the situation can be deduced by analogy, and will not be repeated.

In step S110, the control circuit 101 determines the first component DC current value based on the first comparison result and the first current signal value, wherein the first current signal value is the phase current signal corresponding to the maximum phase voltage control signal value values, and the comparison result of the first comparison line a three-phase voltage control signal value V _a, V _b, V _c the numerical values, the maximum phase voltage control confirmation signal value, and compared to the other two-phase voltage control signal value, Define the intermediate phase voltage control signal value and the minimum phase voltage control signal value. In one embodiment, determining the first component DC current value by the first comparison result and the first current signal value shown in step S110 includes: taking the phase current signal value corresponding to the maximum phase voltage control signal value as the first current signal value and the first comparison result from the phase voltage control signal based value V _a, V _b, V _c define the maximum value phase voltage control signal, an intermediate phase voltage control signal value, a minimum phase voltage control signal value, determined according to The first component DC current value. In practice, the first component DC current value is the product of one half of the difference between the maximum voltage control signal value and the intermediate voltage control signal value and the phase current signal value corresponding to the maximum phase voltage control signal value. The following will illustrate each situation one by one. For example, when voltage V _a is the maximum value of the control signal, V _a> V _b and V _a> V _c, to be taken at this time the equation (1), the maximum value of the phase voltage control signal (V _a) corresponding to the relative phase current The signal value (i _a ) is used as the first current signal value as the main calculation term (ie, i _a is the first current signal value), and the other two voltage control signal values are further judged, which means to compare the magnitude of V _b and V _c . When V _b >V _c , V _b is the intermediate voltage control signal value. The first term in the brackets is established (V _b >V _c ), and the second term is not established (V _b >V _c ), so the first component The DC current value is I _dcia+ =i _a (V _a -V _b /2), which is one-half of the difference between the maximum voltage control signal value (V _a ) and the intermediate voltage control signal value (V _b ) multiplied by The first current signal value. When V _b >V _c , at this time V _c is the intermediate voltage control signal value. The first term in the brackets does not hold (V _b >V _c ), and the second term holds (V _b >V _c ), so the first component is DC The current value is I _dcia+ =i _a (V _a -V _c /2), that is, half of the difference between the maximum voltage control signal value (V _a ) and the intermediate voltage control signal value (V _c ) multiplied by the first A current signal value.

When V _b is the maximum voltage control signal value, V _b >V _a and V _b >V _c , then formula (3) is adopted, and the phase current signal value (i _b ) corresponding to the maximum voltage control signal value (V _b ) ) as the main items of operation (i.e., a first current signal i _b value), the other two further determines a voltage value control signal, which means compare the size of the V _c V _a when V _a> V _c, the intermediate case Va Voltage control signal value. The first term in the brackets is true (V _a >V _c ), and the second term is not true (V _a >V _c ), so the first component DC current value is I _dcib+ =i _b (V _b -V _a /2), that is, one half of the difference between the maximum voltage control signal value (V _b ) and the intermediate voltage control signal value (V _a ) multiplied by the first current signal value (i _b ). When V _a> V _c, V _a at this time is an intermediate value of a voltage control signal, the first term does not hold (V _a> V _c) in brackets, the second set up (V _a> V _c), so that a first DC component The current value is I _dcib+ =i _b (V _b -V _c /2), that is, half of the difference between the maximum voltage control signal value (V _b ) and the intermediate voltage control signal value (V _c ) multiplied by the first A current signal value (i _b ).

When V _c is the maximum value, V _c >V _a and V _c >V _b , then formula (5) is adopted, and the phase current signal value i _c corresponding to the maximum voltage control signal value (V _c ) is used as the main calculation term (i.e., current i _c as a first signal value), the other two further determines voltage control signal value, which means the size of _a comparator V _B and V when V _a> V _b, the intermediate voltage Va at this time the value of the control signal, The first term in the brackets is true (V _a >V _b ), and the second term is not true (V _a >V _b ), so the first component DC current value is I _dcic+ =i _c (V _c -V _a /2), That is, one half of the difference between the maximum voltage control signal value (V _c ) and the intermediate voltage control signal value (V _a ) is multiplied by the first current signal value (i _c ). When V _a> V _b, V _b at this time is an intermediate value of a voltage control signal, the first term does not hold (V _a> V _b) in brackets, the second set up (V _a> V _b), so that a first DC component The current value is I _dcic+ =i _c (V _c -V _b /2), that is, half of the difference between the maximum voltage control signal value (V _c ) and the intermediate voltage control signal value (V _b ) multiplied by the first A current signal value (i _c ).

In step S111, the control circuit 101 uses the second comparison result and the second current signal value to determine the second component DC current value, wherein the second current signal value is the phase current signal corresponding to the minimum phase voltage control signal value The second comparison result is to confirm the minimum phase voltage control signal value, and compare the other two phase voltage control signal values to define the middle phase voltage control signal value and the maximum phase voltage control signal value. In one embodiment, the second comparison result and the second current signal value shown in step S111 are used to determine the second component DC current value, and the phase current signal value corresponding to the minimum phase voltage control signal value is used as the second current signal value, and the second comparison result from the phase voltage control signal based value V _a, V _b, V _c defines a minimum value of the phase voltage control signal, an intermediate phase voltage control signal value, a maximum value of the phase voltage control signal. In practice, the second component DC current value is the product of one half of the difference between the minimum voltage control signal value and the intermediate voltage control signal value and the phase current signal value corresponding to the minimum phase voltage control signal value. The following will illustrate each situation one by one.

For example, when voltage V _a is the minimum value of the control signal, V _a> V _b and V _a> V _c, to be taken at this time the equation (2), the phase voltage control signal to the minimum value (V _a) corresponding to the relative phase current The signal value (i _a ) is used as the second current signal value as the main calculation term (i _a is the second current signal value), and the other two voltage control signal values are further judged, which means to compare the magnitude of V _b and V _c . When V _{When b} > V _c , V _b is the intermediate voltage control signal value. The first term in the brackets is true (V _b >V _c ), and the second term is not true (V _b >V _c ), so the second component DC current The value is I _dcia- =i _a (V _a -V _b /2), that is, half of the difference between the minimum voltage control signal value (V _a ) and the intermediate voltage control signal value (V _b ) multiplied by the first Two current signal value (i _a ). When V _b >V _c , at this time V _c is the intermediate voltage control signal value. The first term in the brackets does not hold (V _b >V _c ), and the second term holds (V _b >V _c ), so the second component is DC The current value is I _dcia- =i _a (V _a -V _c /2), which is one-half of the difference between the minimum voltage control signal value (V _a ) and the intermediate voltage control signal value (V _c ) The second current signal value (i _a ).

When Vb is the minimum voltage control signal value, V _b >V _a and V _b >V _c , at this time formula (4) will be adopted, and the phase current signal value corresponding to the minimum phase voltage control signal value (V _b ) ( i _b) as a second current signal i _b value as the main operation item (i.e., a second current signal i _b value), the other two further determines voltage control signal value V _a comparison of the magnitude V _c which means, when V _a > when V _c, V _a at this time is an intermediate value of a voltage control signal, the first set up (V _a> V _c) in parentheses, and the second term is not satisfied (V _a> V _c), so that the second component of the DC current value I _dcib- =i _b (V _b -V _a /2), that is, half the difference between the minimum voltage control signal value (V _b ) and the intermediate voltage control signal value (V _a ) times the second Current signal value (i _b ). When V _a >V _c , at this time V _c is the intermediate voltage control signal value. The first term in the brackets does not hold (V _a >V _c ), and the second term holds (V _a >V _c ), so the second component is DC The current value is I _dcib- =i _b (V _b -V _c /2), that is, the difference between the minimum voltage control signal value (V _b ) and the intermediate voltage control signal value (V _c ) multiplied by half The second current signal value (i _b ).

When V _c is the minimum voltage control signal value, V _c >V _a and V _c >V _b , then formula (6) will be adopted, and the phase current signal value corresponding to the minimum phase voltage control signal value (V _c ) (i _c) as a second current signal value i _c as a main operation items (i.e., i _c as a second current signal value), the other two parameters further determines voltage control voltage signal, which means compare _a magnitude V and V _B of when V _a> V _b, V _a at this time is an intermediate value of a voltage control signal, the first set up (V _a> V _b) in parentheses, and the second term is not satisfied (V _a> V _b), so that the second component The DC current value is I _dcic- =i _c (V _c -V _a /2), which is _a half of the difference between the minimum voltage control signal value (V _c ) and the intermediate voltage control signal value (V _a ) Upper second current signal value (i _c ). When V _a > V _b , V _b is the intermediate voltage control signal value. The first term in the brackets is not valid (V _a > V _b ), and the second term is valid (V _a > V _b ), so the second component is DC The current value is I _dcic- =i _c (V _c -V _b /2), which is a half of the difference between the minimum voltage control signal value (V _c ) and the intermediate voltage control signal value (V _b ) The second current signal value (i _c ).

The above steps S110 and S111 of concepts in a practical example, in the V _a> case V _b> V _c, since the voltage V _a is the maximum value of the control signal, V _c is the minimum value of the voltage control signal. In the situation where V _a is the maximum value, we will take the formula (1) to do the calculation, using this time as the primary item i _a. When V _c is the minimum value, formula (6) is used for calculation, and i _{c is} used as the main term at this time. The value of the product of the two comparison formulas of the remaining formulas (2) to (5) is zero. Therefore, the calculation result of formula (2) to formula (5) must be zero.

In the case where V _a> V _c> V _b, since V _a is the maximum value of the voltage control signal, V _b is the minimum value of the voltage control signal. In the situation where V _a is the maximum value, we will take the formula (1) to do the calculation, using this time as the primary item i _a. When V _b is the minimum value, formula (4) is used for calculation, and i _{c is} used as the main term at this time. The product of the two comparison formulas of the remaining formulas (2), (3), (5), and (6) is zero. Therefore, the calculation result of formula (2) to formula (5) must be zero.

In the case of V _b >V _a >V _c , since V _b is the maximum voltage control signal value, V _c is the minimum voltage control signal value. When V _b is the maximum value, formula (3) will be used for calculation, and i _{b is} used as the main term at this time. When V _c is the minimum value, formula (6) is used for calculation, and i _{c is} used as the main term at this time. The product of the two comparison formulas of the remaining formulas (1), (2), (4), and (5) is zero. Therefore, the calculation results of formulas (1), (2), (4), and (5) must be zero.

In the case of V _b >V _c >V _a , since V _b is the maximum voltage control signal value, V _a is the minimum voltage control signal value. When V _b is the maximum value, formula (3) will be used for calculation, and i _{b is} used as the main term at this time. V _a is the minimum value in a situation, taking equation (2) do the calculation, using this time as the primary item i _c. The value of the product of the two comparison formulas of the remaining formulas (1), (4), (5), and (6) is zero. Therefore, the calculation results of formulas (1), (4), (5) and (6) must be zero.

In the case of V _c >V _a >V _b , since V _c is the maximum voltage control signal value, V _b is the minimum voltage control signal value. When V _c is the maximum value, formula (5) will be used for calculation, and i _{c is} used as the main term at this time. When V _b is the minimum value, formula (4) is used for calculation, and i _{b is} used as the main term at this time. The product of the two comparison formulas of the remaining formulas (1), (2), (3), and (6) is zero. Therefore, the calculation results of formulas (1), (2), (3), and (6) must be zero.

In V _c> case V _b> V _a, since V _c is the maximum value of the voltage control signal, V _a is the minimum value of the voltage control signal. When V _c is the maximum value, formula (5) will be used for calculation, and i _{c is} used as the main term at this time. V _a is the minimum value in a situation, taking equation (2) do the calculation, using this time as the primary item i _a. The value of the product of the two comparison formulas of the remaining formulas (1), (3), (4), and (6) is zero. Therefore, the calculation results of formulas (1), (3), (4), and (6) must be zero.

In step S120, the control circuit 101 estimates the DC link current value I _DC input to the drive control device 10 according to the sum of the first component DC current value and the second component DC current value. Among them, the aforementioned step S110 and step S111 are executed in no order. That is, step S111 can also be executed before step S110, or step S110 and step S111 are executed together, and the present invention is not limited to the order of execution of the steps in the foregoing embodiment.

In summary, in the DC current estimation device and method proposed in the present invention, the three-phase current signal value of the motor is first fed back, and the control signal is output according to the three-phase current signal value and the command value to control multiple switches , To generate a three-phase voltage control signal, and then further estimate the DC link current value based on the three-phase current signal and the three-phase voltage control signal. In this way, the purpose of monitoring the current value of the DC link can be achieved without additional installation of a DC sensor and without occupying circuit space under the architecture of the original motor drive control system.

Although the present invention is disclosed in the foregoing embodiments, it is not intended to limit the present invention. All changes and modifications made without departing from the spirit and scope of the present invention fall within the scope of patent protection of the present invention. For the scope of protection defined by the present invention, please refer to the attached patent scope.

1: Motor drive control operation system 10: Drive control device 101: Control circuit 1011: First coordinate conversion unit 1012: Current error estimation unit 1013: Current control unit 1014: Second coordinate conversion unit 1015: Signal conversion unit 102: Switch drive Circuit 11: Current detection circuit 12: Power supply source 121: Power supply 122: Capacitor 13: Position sensor 2: Motor I _DC : DC link current T1~T6: Transistor switch S1~S3: Current sensor PS: Position signals I _A , I _B , I _C : phase current i _a , i _b , i _c : phase current signal value V _a , V _b , V _c : phase voltage control signal value V _d , V _q : voltage vector I _d , I _q , V _α , V _β : Variables I _{d_ref} , I _{q_ref} : Command value GS: Control signal

FIG. 1A is a structural diagram of a motor drive control operation system according to an embodiment of the invention. FIG. 1B is an internal functional block diagram of the control circuit shown in the embodiment of FIG. 1A according to the present invention. FIG. 2 is a method flowchart of a DC current estimation method according to an embodiment of the present invention. FIG. 3 is a flowchart of the DC current estimation program depicted in the embodiment of FIG. 2 according to the present invention. FIG. 4 is a detailed flowchart of a DC current estimation program according to an embodiment of the present invention.

Claims (12)

A DC current estimation device suitable for a motor. The DC current estimation device includes: a current detection circuit electrically connected to the motor; the current detection circuit is used for detecting and feeding back the three-phase current of the motor Signal value; and a drive control device electrically connected to the current detection circuit and the motor. The drive control device is used to generate a three-phase voltage control signal value according to the three-phase current signal value and a set of command values, wherein each The phase voltage control signal value corresponds to one of the three-phase current signal values; wherein the drive control device executes a DC current estimation procedure according to the feedback value of the three-phase current signal and the three-phase voltage control signal value, the The DC current estimation procedure includes: judging the magnitude of the three-phase voltage control signal value, and determining the DC current value of a plurality of components according to the judgment result and the value of the three-phase current signal, and inputting the driver according to the DC current value of the components. The DC link current value of the control device. The DC current estimation device according to claim 1, wherein the magnitude of the three-phase voltage control signal value is determined, and the DC current value of the components is determined according to the determination result and the value of the three-phase current signal, and according to the components Estimating the DC link current value input to the drive control device includes: determining the maximum phase voltage control signal value, the middle phase voltage control signal value, and a minimum phase voltage control signal value among the three-phase voltage control signal values; A first comparison result and a first current signal value determine a first component DC current value, wherein the first current signal value is the phase current signal value corresponding to the maximum phase voltage control signal value, and the first The comparison result is to confirm the comparison result of the maximum phase voltage control signal value and the other two phase voltage control signal values; a second comparison result and a second current signal value are used to determine a second component DC current value; The second current signal value is the phase current signal value corresponding to the minimum phase voltage control signal value, and the second comparison result is to confirm the minimum phase voltage control signal value and the other two phase voltage control signals And estimate the value of the DC link current input to the drive control device based on the sum of the first component DC current value and the second component DC current value. The DC current estimation device according to claim 2, wherein determining the first component DC current value based on the first comparison result and the first current signal value includes: the maximum phase voltage control signal value corresponding to the The phase current signal value is used as the first current signal value, and the other two-phase voltage control signal values are compared to define the intermediate phase voltage control signal value and the minimum phase voltage control signal value to determine the first Component DC current value. The DC current estimation device according to claim 3, wherein the first component DC current value is a half of the difference between the maximum phase voltage control signal value and the intermediate phase voltage control signal value and the maximum phase The product of the current signal value of the phase corresponding to the voltage control signal value. The direct current estimation device according to claim 2, wherein determining the second component direct current value based on the second comparison result and the second current signal value includes: using the minimum phase voltage control signal value corresponding to the The phase current signal value is used as the second current signal value, and the other two-phase voltage control signal values are compared to define the intermediate phase voltage control signal value and the maximum phase voltage control signal value to determine the second current signal value. Component DC current value. The DC current estimation device according to claim 5, wherein the second component DC current value is a half of the difference between the minimum phase voltage control signal value and the intermediate phase voltage control signal value and the minimum phase The product of the current signal value of the phase corresponding to the voltage control signal value. A method for estimating DC current includes: detecting and feeding back a three-phase current signal of a motor with a current detection circuit; and using a drive control device to generate three-phase current signals based on the three-phase current signal value and a set of command values Voltage control signal value; and the drive control device executes a DC current estimation procedure according to the feedback of the three-phase current signal value and the three-phase voltage control signal value; wherein the DC current estimation procedure includes judging the three-phase The magnitude of the voltage control signal value is determined according to the judgment result and the value of the three-phase current signal to determine the DC current values of multiple components, and the DC link current value input to the drive control device is estimated according to the DC current values of the components. The DC current estimation method according to claim 7, wherein the magnitude of the three-phase voltage control signal value is determined, and the DC current value of the components is determined according to the determination result and the value of the three-phase current signal, and according to the components Estimating the DC link current value input to the drive control device includes: judging the maximum phase voltage control signal value, the minimum phase voltage control signal value, and the intermediate phase voltage control signal value among the three-phase voltage control signal values; A comparison result and a first current signal value determine a first component DC current value, wherein the first current signal value is the phase current signal value corresponding to the maximum phase voltage control signal value, and the first comparison result Is to confirm the maximum phase voltage control signal value and the comparison result of the other two phase voltage control signal values; a second comparison result and a second current signal value are used to determine a second component DC current value, where the second The current signal value is the phase current signal value corresponding to the minimum phase voltage control signal value, and the second parameter comparison result is to confirm the minimum phase voltage control signal value and the other two phase voltage control signal values Comparison result; and estimate the value of the DC link current input to the drive control device according to the sum of the first component DC current value and the second component DC current value. The direct current estimation method according to claim 8, wherein determining the first component direct current value based on the first comparison result and the first current signal value includes: using the maximum phase voltage control signal value corresponding to the The phase current signal value is used as the first current signal value, and the other two-phase voltage control signal values are compared to define the intermediate phase voltage control signal value and the minimum phase voltage control signal value to determine the first Component DC current value. The DC current estimation method according to claim 9, wherein the first component DC current value is a half of the difference between the maximum phase voltage control signal value and the intermediate phase voltage control signal value and the maximum phase voltage The product of the current signal value of the phase corresponding to the control signal value. The direct current estimation method according to claim 8, wherein determining the second component direct current value based on the second comparison result and the second current signal value includes: using the minimum phase voltage control signal value corresponding to the The phase current signal value is used as the second current signal value, and the other two-phase voltage control signal values are compared to define the intermediate phase voltage control signal value and the minimum phase voltage control signal value to determine the second current signal value. Component DC current value. The direct current estimation method according to claim 11, wherein the second component direct current value is a half of the difference between the minimum phase voltage control signal value and the intermediate phase voltage control signal value and the minimum phase The product of the current signal value of the phase corresponding to the voltage control signal value.

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