Electrical angle detecting device and synchronous motor drive device

An electrical angle detecting device of a synchronous motor whose rotor is driven to rotate by interaction between a magnetic field produced by windings upon passage of polyphase currents therethrough and a magnetic field produced by permanent magnets, said device comprising:

• memory means for storing in advance relationships between electrical angle and behavior of currents passing through polyphase windings in response to a prescribed voltage applied to a combination of said polyphase windings through which currents pass,
• voltage applying means for applying a voltage to said combination for shorter than a time period required for a change in electrical angle of .pi., said time period being a function of an upper limit speed of said motor subjected to electrical angle detection, said voltage including only one voltage pulse used for detecting an electrical angle,
• current behavior detecting means for detecting said behavior of said currents passing simultaneously through each of said polyphase windings in response to said only one voltage pulse which has been applied,
• angle detecting means for determining said electrical angle of said motor in a 0-.pi. range or a .pi.-2.pi. range thereof based on said behavior of said currents in said windings detected by said current behavior detecting means by referring to said relationships stored in said memory means,
• range ascertaining means for at least once ascertaining in which of said 0-.pi. range and said .pi.-2.pi. range said electrical angle falls, and
• electrical angle update means for determining an initial value of said electrical angle from said detected electrical angle and a result of ascertaining by said range ascertaining means in the range 0-2.pi. and updating said current electrical angle using said electrical angle detected thereafter by said angle detecting means.

An electrical angle detecting method for detecting an electrical angle of a synchronous motor whose rotor is drive to rotate by interaction between a magnetic field produced by windings upon passage of polyphase currents therethrough and a magnetic field produced by permanent magnets, said method comprising:

• (a) applying a prescribed voltage to a combination of polyphase windings of said synchronous motor through which currents pass and in advance storing in memory relationships between electrical angle and behavior of currents passing through said polyphase windings in response to said applied voltage,
• (b) applying a voltage, which includes only one voltage pulse used for detecting an electrical angle, to said combination,
• (c) detecting said behavior of said currents passing simultaneously through each of said polyphase windings in a range of 0 to 2.pi. in response to said only one voltage pulse which has been applied as a unique combination of electrical currents passing through said polyphase windings, and
• (d) determining said electrical angle of said motor between 0 and 2.pi. based on said detected behavior of said currents in said windings by referring to said relationships stored in memory.

An electrical angle detecting method for detecting an electrical angle of a synchronous motor whose rotor is driven to rotate by interaction between a magnetic field produced by windings upon passage of polyphase currents therethrough and a magnetic field produced by permanent magnets, said method comprising:

• (a) applying a prescribed voltage, which includes only one voltage pulse used for detecting an electrical angle, to a combination of polyphase windings through which currents pass a plurality of times and in advance storing in memory relationships between electrical angle and corresponding behavior of currents passing through said polyphase windings in response to said voltage applied a plurality of times,
• (b) repeatedly applying said voltage, which includes only one voltage pulse used for detecting an electrical angle, to said combination for a time period shorter than that required for a change in electrical angle of .pi., said time period being a function of an upper limit speed of said motor subjected to electrical angle detection,
• (c) detecting said behavior of said currents passing simultaneously through each of said polyphase windings in response to each of said only one voltage pulse which has been applied by said step of repeatedly applying,
• (d) determining said electrical angle of said motor in a 0-.pi. range or a .pi.-2.pi. range thereof based on said detected behavior of said currents in said windings by referring to said relationships stored in memory,
• (e) at least once ascertaining in which of said 0-.pi. range and said .pi.-2.pi. range said electrical angle falls, and
• (f) determining an initial value of said electrical angle from said detected electrical angle and a result of ascertaining by said range ascertaining step in the range 0-2.pi. and updating said current electrical angle using said electrical angle detected thereafter.

A synchronous motor drive device of a synchronous motor whose rotor is driven to rotate by interaction between a magnetic field produced by windings upon passage of polyphase currents therethrough based on an electrical angle of said rotor and a magnetic field produced by permanent magnets, comprising:

• memory means for storing in advance relationships between electrical angle and behavior of currents passing through polyphase windings in response to a prescribed voltage applied to a combination of said polyphase windings through which currents pass,
• voltage applying means for applying said voltage to said combination, said voltage including only one voltage pulse for detecting an electrical angle,
• current behavior detecting means for detecting said behavior of said currents passing through each of said polyphase windings in a range of 0 to 2.pi. in response to said only one voltage pulse applied by said voltage applying means as a unique combination of electric currents passing through said polyphase windings,
• electrical angle computing means for determining said electrical angle of said motor between 0 and 2.pi. based on said behavior of said currents in said windings detected by said current behavior detecting means by referring to said relationships stored in said memory means,
• torque command value inputting means for inputting a torque command value related to torque required of said synchronous motor, and
• current controlling means for controlling current passed through said polyphase windings based on said electrical angle determined by said electrical angle computing means and said input torque command value.

A synchronous motor drive device of a synchronous motor whose rotor is driven to rotate by interaction between a magnetic field produced by windings upon passage of polyphase currents therethrough based on an electrical angle of said rotor and a magnetic field produced by permanent magnets, comprising:

• memory means for storing in advance relationships between electrical angle and behavior of currents passing through polyphase windings in response to a prescribed voltage applied to a combination of said polyphase windings through which currents pass,
• voltage applying means for applying said voltage to said combination, said voltage including only one voltage pulse for detecting an electrical angle, for shorter than a time period required for a change in electrical angle of .pi., said time period being a function of an upper limit speed of said motor subjected to electrical angle detection,
• current behavior detecting means for detecting said behavior of said currents passing through each of said polyphase windings in response to said only one applied voltage pulse,
• angle detecting means for determining said electrical angle of said motor in a 0-.pi. range or a .pi.-2.pi. range thereof based on said behavior of said currents in said windings detected by said current behavior detecting means by referring to said relationships stored in said memory means,
• range ascertaining means for at least once ascertaining in which of said 0-.pi. range and said .pi.-2.pi. range said electrical angle falls, and
• electrical angle update means for determining an initial value of said electrical angle from said detected electrical angle and a result of ascertaining by said range ascertaining means in the range 0-2.pi. and updating said electrical angle using said electrical angle detected thereafter by said angle detecting means,
• torque command value inputting means for inputting a torque command value related to torque required of said synchronous motor, and
• current controlling means for controlling current passed through said polyphase windings based on said electrical angle updated by said electrical angle update means and said input torque command value.

A synchronous motor drive method of a synchronous motor whose rotor is driven to rotate by interaction between a magnetic field produced by windings upon passage of polyphase currents therethrough based on an electrical angle of said rotor and a magnetic field produced by permanent magnets, said method comprising:

• applying a prescribed voltage to a combination of polyphase windings through which currents pass and in advance storing in memory relationships between electrical angle and corresponding behavior of currents passing through said polyphase windings in response to said applied voltage,
• applying said voltage to said combination which includes only one voltage pulse for detecting an electrical angle,
• detecting said behavior of said current passing simultaneously through each of said polyphase windings in a range of 0 to 2.pi. in response to said only one applied voltage pulse as a combination of electric currents passing through said polyphase windings,
• determining said electrical angle of said motor between 0 and 2.pi. based on said detected behavior of said currents in said windings by referring to said relationships stored in memory, and
• controlling current passed through said polyphase windings based on said determined electrical angle and a torque command value for said motor.

A synchronous motor drive method of a synchronous motor whose rotor is driven to rotate by interaction between a magnetic field produced by windings upon passage of polyphase currents therethrough based on an electrical angle of said rotor and a magnetic field produced by permanent magnets, said method comprising:

• applying a prescribed voltage to a combination of polyphase windings through which currents pass and in advance storing in memory relationships between electrical angle and corresponding behavior of currents passing through said polyphase windings in response to said voltage applied a plurality of times,
• repeatedly applying said voltage which includes only one voltage pulse used for detecting an electrical angle to said combination for a time period shorter than that required for a change in electrical angle of .pi., said time period being a function of an upper limit speed of said motor subjected to electrical angle detection,
• detecting said behavior of said current passing simultaneously through each of said polyphase windings in response to each of said only one voltage pulse which has been applied by said step of repeatedly applying,
• determining said electrical angle of said motor in a 0-.pi. range or a .pi.-2.pi. range thereof based on said detected behavior of said currents in said windings by referring to said relationships stored in memory,
• at least once ascertaining in which of said 0-.pi. range and said .pi.-2.pi. range said electrical angle falls,
• determining an initial value of said electrical angle from said detected electrical angle and a result of ascertaining by said range ascertaining step in the range 0-2.pi. and updating said electrical angle using said electrical angle detected thereafter, and
• controlling current passed through said polyphase windings based on said updated electrical angle and a torque command value for said motor.